The Time Line of Life
The Second Great Lesson
There are many that encourage us to get all the great lessons done in 6 to 8 weeks, but I have found that late October works best for me. I think there is so much more material to study and read then when Montessori began these lessons, that to go any faster feels like I'm pushing the class rather than following it. So, I wait until at least half of the reports are edited and most of the others are waiting to be edited. You should feel a lull in the excitement of the class, then you will know it is time.
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Continue reading The Universe Story until humans appear. The Evolution Book by Sara Stein is also easy and good. If you get into it, Wonderful Life by Stephen Jay Gould which is all about the Burgess Shale in Canada is amazing and for readers who like humor in heavy science should read Planet Ocean by Brad Matsen & Ray Troll.
You should also brush up on you classification. You need to know The Five Kingdoms - which means you have to have good notes or have a good book. You should also at least know the Phylum categories for invertebrates and for vertebrates, the phylum and class.
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Setup and Presentation
I gather everyone around the Time Line. I use the Albanesi purchased Time Line. There are better ones that are more up to date, but it really doesn't matter - it is after all an impressionistic lesson and research will reveal the holes and mistakes. If I have strong third graders that knows a lot, then I make this lesson optional for them. It's so touching, when they say no and continue with work instead, they still watch and then they hover around the outskirts and pretty soon they are answering questions. This work truly calls to these students.
I open the Time Line just a bit so all they can see are the bacteria. If some complain they cannot see, remind them the work will be in the room all year and they can take it out again and again. I ask them what had happened with Earth in the story I had told a few weeks before. Ask questions back and develop these answers until everyone has a good mental picture. You can tell by their faces. Then I start with how the air became acidic and how air, wind and rock argued and begin the story of life.
I add much personification to the changing of life when I go through the periods, slowly unfolding the Time Line as we look. I do not tell the story I have provided word for word as the students are just too excited looking at all the life to listen. I may do the whole timeline again the next day and tell the story more formally. I have also split the story over several days if the students have a lot of questions and it goes on too long.
We explore how life changed by having cells that compartmentalized. I always tell what each period and Era means and what animals were dominant at that time. We talk about how the armored fish were slow and heavy and that Sea Scorpion, the Pterygotus, could crunch through any armor with his claws. They love that. The cephalopod with its feet on its head - we all put our hands on our heads. The fish had to have a way to get away or they would have gone extinct so they dropped their armor and developed fins and swam too fast for the Sea Scorpion who still had heavy armor. Then how lobe finned fish slowly were drawn to the land that had so many insects and plants. Of course they could not go far from the water. Why is that - tell me about amphibians. So one day an amphibian really wanted a tasty bug - I pick one student to lick my lips at... So it changed so it could leave the water and get those bugs. How did it change? What are reptiles like? Then the insects developed wings to get away, so the reptiles did too. They love their bugs. Wow, remember how those fish and arthropods got so big? The reptiles got bigger and bigger and one special group developed special hips and became dinosaurs. Does anyone know what happened to the dinosaurs? We talk about asteroids and what happened to life. There were so many opportunities for life to end, but here we are. We talk about what would happen if there were no bacteria. All those dinosaurs would still be lying around.
Then the mammals took over and soon, they too were huge. We talk only briefly about the human at the end as this is another story...
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Story of Coming of Life
Well, let's see.. where did we leave off? ( Look to children)
volcanoes: yes, the earth's crust had formed and wrinkled and some of the trapped particles were hot and they expanded.
Cold: yes, it was colder than our coldest night.
The balloon: yes, the particles came together and then exploded to form the universe.
Four and ½ billion years ago a very special event occurred. As the particles surrounding our star pulled together, a planet named Earth was formed. The particles eventually settled down according to their own nature, there were solids, like the rocks, liquids, like water and gasses like the air. But the air was nothing like the air of today. Scientists believe the sky was a pretty orange color. It was late in the Proterozoic Era in the Precambrian Period.
Remember how Earth had cooled enough for rain to fill all the hollows and how the volcanoes still burst through the crust? Well, the air was made up of methane, hydrogen, ammonia, carbon dioxide, nitrogen and sulfur. This (open a bottle of ammonia) will give you an idea of how it smelled. Now imagine the rotten egg smell of sulfur mixed in. This made rain acidic and began to wash the minerals from the rocks. The seas were full of the elements from the air and minerals from the rocks. Gigantic electrical storms also raced back and forth across Earth's surface. Lightning passed through the seas and made a simple food, but there was nothing in the seas to eat this broth.
And then something happened - 500 million years had passed - and a most amazing something happened! It was so tiny that it could hardly be seen. These tiny particles had what no others had ever had before: the ability to make more of themselves. No matter that four billion years have passed since that day; these tiny organisms still live today. These organisms were also unique in that they changed slightly as they made more. We have named them prokaryotes in the Kingdom Monera. (If you have pictures of bacteria, show them now.) These bacteria thrived however and filled the seas and even moved onto rock. This caused more weathering of the rocks which released more carbon dioxide and this in turn made Earth hotter. This new life loved heat, so they made even more of their own kind.
This life continued to make more until they had consumed so much food that it became scarce. Some prokaryotes changed to eat the waste of others or dead organisms. Thus the first scavengers appeared. Others started using sunlight for its food and oxygen was released into the air for the first time. We have named this new bacteria that used sunlight or photosynthesis cyanobacteria. When cyanobacteria first released oxygen it just combined with rocks - this is why Earth has large layers of rust in its history. Then there was so much oxygen that the rocks could no longer hold it and Earth's atmosphere began to change. Oxygen was poisonous to the earliest forms of life so they retreated to places where oxygen could not reach them like the deepest parts of the ocean. We call these the Archaebacteria. The oxygen moved up to form the ozone layer Earth still has today. This ozone layer permitted life to move onto the land and still protects all life on Earth today.
Around the same time that cyanobacteria evolved, a new life that was more complicated appeared. We call this new life eukaryote. It lives on in many kingdoms - the Protist, Plantae, Fungi and Animalia, but at first only large unicellular organisms of the Protist Kingdom filled the seas. This new life could eat other smaller life. The predator - prey relationship that would soon fill the seas began. Some eukaryotes tried to eat smaller bacteria, but the bacteria just continued living inside them. These eukaryotes had more energy and efficiency them any had before as the little life inside them helped them. This mixing of two organisms eventually led to changes that happened more quickly than before. As life drifted in the seas some of them joined together. At first they lived as the porifera do today - individuals that live together in a colony, but towards the very end of this time, some cells began to join together. Cells began to share work. Some took on the job of eating, some did the breathing and some did the moving about. Scientists have named these more complicated animals the Ediacara Life. They lived mostly on the seafloor. They did not yet have shells, so we don't know much about them. Earth experienced a great many volcanic eruptions at this time which caused the climate to cool, but finally the ice melted and the great continent Gondwana formed along with 4 other smaller continents. The water was warm and shallow and life filled the seas. Let's open the timeline and look at some of these new organisms.
(Open timeline to show all of the Paleozoic Era. Expect a lot of comments and excitement. You may not be able to tell all the story. That's okay - you have time another day - or use your journals to expand.)
The Paleozoic Era is broken into six periods. This is the Cambrian Period. We can tell a lot about the animals of this time as many had developed shells which fall back onto the seabed and become fossils. A lot of the invertebrate organisms we see on Earth today had their beginnings way back here in the beginnings of the history of life and a lot of life disappeared never to be seen again. Arthropods made up 2/3 of all life in the seas at this time. There were a lot of trilobites. They came in all sizes, really big to really tiny and they had bodies that were segmented lengthwise. They probably had the first well developed eyes. Very early vertebrates also appeared. Vertebrates have a main nerve column running down the center of their back. You can feel yours in the middle of your back, but these vertebrates were very simple. They looked mostly like simple fish. The Cambrian Period is often called the time of the explosion of life.
The Ordovician Period started 500 million years ago. The cystoids began to rule the seas. They lived by the banks of the oceans in the shallow water, but they held onto the rocks very tightly. When they were hungry they used their arms and pushed the water into their mouths. These cystoids had hard shells around their bodies and they too helped to build up the banks at the edge of the sea when they died. Corals also appeared to build huge reefs. New larger predators appeared. These were the cephalopods. They had their arms on their heads. They developed beaks that could crack through shells. Then the trilobites developed even stronger shells. Some cephalopods shells had pretty patterns just as they do today and may have even been beautifully colored.
At the beginning of the Silurian period there was another ice age. The super continent named Laurasia was formed. Some of the oldest mountains on Earth were formed - like the Urals in Russia and Appalachians in North America. Life on Earth again changed as the seas rose and then fell again. Primitive fish started to fill the seas. At first they were jawless and sucked up their food from the sea floor. They were covered by bony plates of armor for protection. We call these fish ostracoderms. Later, towards the end of the Silurian Period, these fish had developed jaws and fins. They were now covered in small, overlapping scales like today's fish. They were definitely predators as they had jaws that could open very wide and had teeth. Do you think they dropped their heavy armor so they could swim faster to escape the sea scorpion?
The land on Earth was still a very hostile place. Volcanoes were still erupting pretty regularly, strong winds roared over the land and sunlight shone fiercely. There were only rocks as soil had not yet formed. Algae lived in huge beds of seaweed. They don't need roots as water swirled all around them. As it floated it sometimes was washed up onto shore by the waves. At first they probably died, but some were helped by fungi which acted like roots for them and began to survive at the muddy edge of the land. Fungi and bacteria joined the plants and the first soil was formed. They developed spores that were blown away by the wind. If these spore landed on swampy areas, they began to grow. Earth was slowly changed.
By the Devonian Period the plants had evolved stiff fibers to stand up tall roots and leaves. There were huge forests of ferns. The Fungi joined them. They help decompose dead organisms and plant material just as the bacteria does. Soil is formed in this way. Some of the seas arthropods began eyeing this new land. It had plenty of food and no predators. Their exoskeletons held all the water they needed inside and so the plants were joined by insects. Large predators, of course, soon followed. Scorpions with limbs armed with pincers joined the insects. Spiders, too.
The seas were full of fish. There were fish with bony armor, fish with scales, fish with and without jaws, fish with cartilage and fish with bones. There was also a special kind of fish that had fleshy, muscular fins called lobed fins. Most fish have bony fins called ray fins. These fish with lobe fins also had a swim bladder to help them float. Sometimes fish got caught in swampy ponds as the water level went up and down. The fish would gulp air at the surface to stay alive. They could see all the insects waiting for them up on land. A special change allowed them to twist and wriggle on their fleshy, lobe fins and the first amphibian walked out onto land. If you watch a newt walk, you can still see how it wriggles its body side to side just like a fish. The land on Earth now had life.
During the Carboniferous Period the climate was warm and damp and huge swampy areas of giant ferns flourished. As these fern forest died, they could not be broken down and as they were covered in sediment they formed the giant coal beds that we still use for fuel today. Some of the animals were tired of having to live near the water. They wanted to go further away from the water so they could get more of those luscious insects for dinner. So gradually they developed a skin that would not dry out, even under the hottest sun, and they laid eggs with tough shells that would protect them. Their skulls made a slight change too. Amphibians have a solid skull with only holes for their eyes. They don't have to walk very far or very fast, so it doesn't matter. As they evolved into reptiles, their skull developed two more holes which helped make the skull lighter. They were called reptiles. They lived in the tall grass and ate insects. In response insects developed wings so they could escape.
The Permian Period marks the end of the Paleozoic Period. The continents all came together into one large land mass named Pangaea. The climate became drier. This caused the over half the species of amphibians which had evolved into forms over 7 feet long to die off , but the reptiles loved the heat and flourished. They began growing larger and fiercer. Some returned to the sea. Some reptiles changed so that they had only one skull onpening other than their eyes - they were the reptiles that would become mammals. Some of these mammal-like reptiles were large with huge sails on their backs. They probably used these sails to absorb heat from the sun.
As the climate continued to get drier, seas and lakes were drying up and becoming very salty. Almost all the life in the shallow water died and most spore producing ferns died along with them. Almost half of all animal life disappeared. The mighty trilobites that had filled the seas and the armored ostracoderms were no more. It was the worst extinction of life that Earth had ever known.
(Keep opening timeline to continue) The Mesozoic Era is the middle life's history on Earth. In the Triassic Period, new life appeared to replace the life that had died. Life such as oysters, snails, lobsters and clams filled the shallow seas again. Large reptiles were the largest predators in the seas. Some reptiles changed so that they could be active even when it was cool. These were the warm blooded cynodonts. They may have had fur to help keep them warm. They could feed at night when other reptiles could not. This was very important to their survival because some reptiles were becoming huge. This was the age of the dinosaurs. They grew to enormous sizes. These big reptiles ate almost anything. Some reptile had developed flaps of skin so they could glide from tree to tree, but now the first true flying reptiles, the pterosaurs appeared.
The Jurassic Period saw a return of a more rainy climate. Conifer forests, ferns and cycads again began to cover the land. Pangaea began to break apart. Pterosaurs filled the skies as they perfected their flying skills. Towards the end, true birds appeared. Teeth were replaced by a toothless beak and changes in muscle structure allowed wings to flap. The most common dinosaurs were the sauropods. These were huge animals with long necks. Huge bipedal - two legged - predator dinosaurs with powerful claws looked for unsuspecting prey. Some of this prey were warm blooded animals that lived on the edges of lakes and swamps. They were plant eaters.
The Cretaceous Period was a time when beautiful colors filled the forests and life again went through a great mass extinction. Flowers had evolved. The duckbilled dinosaurs appeared in great herds. Triceratops, one of the last dinosaurs, also appeared. Crests, frills and strange horns were common. Tyrannosaurs were fearsome predators. Smart raptors with a slicing hind claw hunted together and became Earth's most successful predators. Perhaps the climate cooled again and animals that could not adapt died off. Perhaps a giant asteroid hit Earth and a cloud of dust rose up that blocked the sun. Many volcanoes were again erupting which would also cause a cooling of the climate. In any case, much of Earth's life and all the dinosaurs died. Remember those warm blooded reptiles? Well some of these animals developed into marsupials. They produced milk to feed their young.
The Cenozoic Era saw the end of the great carnivores although large mammals slowly evolved to take their places. The mammals now began to take over the land. Shrew like insect eaters competed with the remaining amphibians. Some mammals took to the air and some returned to the sea. The mammals quickly evolved to fill up every habitat and to eat every type of food. A new mammal, the primate, appeared about 65 million years ago. The monkeys evolved first and then the apes. At the very end of the time life has been on Earth - only 4 million years ago - a new primate walked on land on two legs. This story is our story and will be told another day.
Earth without them.
You know what though? Many scientists still say we are in the Age of Bacteria. There are more bacteria on Earth than any other organism. What a shame we do not recognize their importance and variety. No life would be on Earth as we know it, if not for them and in fact no life could even now exist on Earth without them.
I start journal entries the next day, usually for only one week as they are into work now and sometimes resent the time it takes. These may not have books to look at. I may just have the time line laid out or materials I have made. Again, they all write down the date and entry and then go into their answer to the question. I often use these journal entries to introduce new work. This year I bought new work on the 5 Kingdoms so I laid it our for a journal entry on classification - I give a lesson to the first few who enter and then they have to give the lesson and then those give a lesson until we all gather to talk about the why there is classification.
I tell them that they may choose the time line for a research. When I first started, we did the time line as a class work and it is lots of fun. One year we pasted our back wall with pictures of animals and short stories about them. Another year we put a round table and a rectangular table together and made the round table the sea and the rectangular table the land and made a time line with clay figures and paper trees etc. If you are behind in research or have a class new to research this is a good way to give yourself a bit of a respite while still doing cosmic work.
I have made 10 large, plastic envelopes labeled for each period. Inside I have all the pictures, words and maps for the period. Code the back of each card with the same name as the envelope or face sorting them when they all get mixed up.
The requirements for Time Line research are that they write about each animal they find and about the geology and climate for every period. I challenge them to find new animals, sometimes marking hard, adult books for them with stickies - like Jay Gould's book - to show different ones. I encourage younger students to pick one period to start with, and then go on to another. Once a period is chosen, the next group has to choose a different one. Two or three students can work on each period. The draw all animals free hand.
I have included language cards that match the Albanesi Time Line, but many of the known animals are the same on many timelines, so they should work regardless - or they can be new animals. I double mat the cards on different colors for each Kingdom and phylum. This way an older child can sort through all the envelopes and do a research on all arthropods or other animals through time. Time can go horizontally or vertically.
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The week after this lesson I begin with the 5 Kingdoms. Zoology now fills the classroom. I go through the vertebrates, usually starting with fish and amphibians the first week. The third graders dissect the biggest fish I can find. I introduce how strange the classification of fish is, as there is no word fish. I have never found out why this is so... Anyone know? Most of my students know the Kingdom, Phylum, Class and Order of their animals. i.e.. A snake is Animalia, Chordata, Reptilia, Squamata. Birds and mammals are the hardest as their are so many different kinds, but that is exciting in itself. I have included some simple cards in the language section to teach this with. Michael Olaf sells a great book called Latin Names Made Simple that I highly recommend. It explains what many of the Latin names mean or how they came to be.
Reptiles bring in dinosaur work. I have included possible research cards in the language work. I have also purchased sets of dinosaurs - see resources. I have made up
phrases to match them and the students can then take the phrases and make sentences or stories with them.
Birds are always a favorite research. Do not leave out geography. I have laminated pictures of say types of tigers that note where they live on the back. Students can then make a map and learn how to make colored keys to show where animals live.
Reports on animals always begin with their classification. I only let one student research alone for one animal. In order to work in groups they have to do say all poisonous snakes, splitting them up evenly or all the hummingbirds. I also encourage research by biomes. There are many bird books now that have birds classified by where they live or even how they sing. They are listed in resources. Of course, the favorite fish research is sharks
If you have a strong third grade that has done much vertebrate research, bring in invertebrate research. Spiders are a strong favorite, ants and bees are very interesting and scorpions are researched almost every year.
I save mammals until after Early Humans for selfish reasons. The students so love mammals that all other research would stop and all they would do is animals, so I stall until three lessons have been given.
- The Black Strip
- The Clock of Ears
- Sedimentary Rocks
Calendar work can now begin. Many enjoy family time lines after looking at Earth's. We also do a calendar of our day in a pie graph form. You'd be surprise how many do not know when they eat supper or leave for school. I think students need to develop an awareness of their day.
Ribbon For the Black Strip: I have a colored ribbon in the room. The students take it outside and weave their own tale. 1" = 10,000,000 years
Earth's Calendar in months
||black (no life)
|| turns yellow: life appears
||stomatolites (large groups of bacteria) appear
|Sept. 9 (3.1 billion years)
|| green algae, oxygen appear
||blue algae appears
|| trilobites appear
||armored fish, plants appear
||land animals: arthropods appear
|Last 2 hours of Dec. 31
|Last minute of Dec. 31
Earth's Calendar in Hours
||5 trillion years ago the solar system forms
||rocks form on Earth
||Earth has its present composition
||First evidence of life
||5 continents appear: N. A., Europe, Siberia, China and Gondwanaland
||Photosynthetic algae and fungi appear - oxygen atmosphere
||invertebrates with shells appear
||insects appear on land
||Dinosaurs become extinct
||Continents take present positions
||Large ice mammals
Commands to Life
- Unite (sponges)
- Cooperate (differentiated cells)
- Create and Preserve Harmony (cosmic task)
- Create a more efficient love (mammals)
- Take, but give in return ( breathe out to feed the plants)
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The universe was born 15 billion years ago. Five billion years ago the Milky Way was born. Earth was born 4 ½ billion years ago. Life on Earth began 4 billion years ago. What was the first life and what did it give us?
Scientists have divided life on Earth into five kingdoms. What are the five kingdoms? Why do we need to classify life?
We are grateful to Bacteria for making Earth's atmosphere. Bacteria are the hardiest of all organisms as they can live in the most hostile and varied environments. What Kingdom are they in? Why is an atmosphere important?
Protoctista or Protista is a complex Kingdom that may some day be divided into smaller groups. Find the names of some of the organisms classified in this Kingdom. Tell a little bit about it.
All animals are in the Kingdom Animalia. Can you name all five vertebrate classes? Can you find some of the names for the phylum of invertebrates?
Fungi are unusual as they live mostly underground. They are like humans in that they cannot make their own food from sunlight. Lichen is grouped with the fungi. Why is this not really a good match?
Plants are grouped in the Kingdom Plantae. It includes trees, bushes, flowers, seaweed and the brave algae (the first plant brave enough to go on land.) What do all plants have in common that no other organism can do?
Five hundred million years ago the seas covered most of Earth. This is called the Paleozoic Era. The Cambrian Period hosted an explosion of life. The first new invention was that of the hard shell. What advantages or disadvantages does a shell give?
Vertebrates are animals that have backbones. The fish is the simplest vertebrate and was the first vertebrate to appear on Earth. The fish was the first animal to develop a jaw. What is unusual about the classification of fish? What are the three phylum?
Sharks are fish that have cartilage instead of bones. Sharks live in the warm oceans of the world. What is the largest shark? What is the smallest shark? What is your favorite? What fish are related to the shark and in the same classification?
There are some very unusual kinds of fish. Some can use their bony, lobe-shaped fins to walk from pond to pond and some can fly through the air to escape predators. The most unusual, however, are the deep sea fish.
The most varied amphibian is the poison dart or arrow frogs. They live in South America and are used by some native people to poison their arrows for hunting. What are the different classifications of these frogs?
The amphibians once ruled Earth. Now there are only 3 phylum left. Why is the amphibian less hardy than other vertebrates?
Reptiles evolved from the amphibians. What are the characteristics that changed and why do you think they changed? What are the four phylum of reptiles?
Dinosaurs were the largest land animals to ever live. What classification of dinosaur evolved into a species still on Earth today? Why did dinosaurs disappear in the Cretaceous Period?
Snakes are reptiles that do not have legs. Only certain snakes are venomous. Many are very important to our environment as they eat small mammals. Why and how does a snake shed its skin?
What characteristics did birds develop so that they can fly? What makes a bird a bird?
Some birds do not fly. What are some of the other ways that birds use for movement?
Birds all care for their young. This is the first species to universally care for their young. What advantage does this give them?
Birds of prey eat meat. They have sharp claws called talons. Their beaks are specially formed to rip meat off their prey. They also have special feathers to help them dive. How many different kinds of raptors can you name?
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Language Cards of Dinosaurs
Dinosaurs Card 1
1. Choose three dinosaurs and tell about them.
2. Name two meat eating dinosaurs and two plant eating dinosaurs.
3. Find two dinosaurs that lived in each of the following periods: Triassic, Jurassic and Cretaceous
Dinosaurs Card 2
4. How did the following dinosaurs protect themselves?
- Tyrannosaurus Rex
5. Explain the difference between the teeth of a meat eating and plant eating dinosaur.
6. Look up the meaning of the following names:
Dinosaurs Card 3
7. Make a chart of all the meat eating dinosaurs and all the plant eating dinosaurs. Put a human on your chart.
8. Make a graph of the height of 5 or more dinosaurs.
9. Compare the climate of the Triassic. Jurassic and Cretaceous Period.
Dinosaur Card 4
10. What is your favorite dinosaur? Why?
11. If you lived while dinosaurs were around, which one would you have for a pet? why?
12. You are walking in the woods and find a baby dinosaur. Tell what it looks like and then design a park that the dinosaur could live in.
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Language Cards for Time Line Research
(Each card is doubled matted by kingdom and phylum - see Follow Up)
Earth was born around 4.5 billion years ago. At first it was just a swirling mass of dust, elements and particles, but soon it developed gravity and formed a crust. Volcanic eruptions caused the atmosphere to fill with poisonous gases.
Proterozoic comes from the Greek word Protero or early and zoic or life. The Earth's crust had formed. There were still many volcanoes erupting and earthquakes. By the end of this era, the Earth's crust was cool and the first ice age took place. Ice covered the Northern and Southern Hemispheres. The first life began to appear.
The organisms of the Monera Kingdom were the first life on Earth. This kingdom has more organisms than any other. They are so small, however, that we are unaware of them. You would need a microscope to see them. These small organisms were to have a tremendous impact on our Earth and its history.
Paleozoic comes form the Greek word Paleo or old and zoic or life. This Era covers six periods. It is the longest on the time line. All life lived in the oceans that covered most of Earth. There was no ozone so the ultraviolet rays of the sun beat down on Earth.
A new kingdom of life appeared at the end of the Precambrian Period. These protists had were also unicellular, but they had chlorophyll. They could use sunlight , water and the carbon dioxide given off by the monerans. They then gave off oxygen into the air. Protists sometimes lived in colonies.
Bacteria are very hardy organisms. Even today they live in freezing, moderate and boiling environments. The bacteria lived on minerals that had washed into the seas or organic waste. They have lived longer than any other organism on Earth.
Algae is sometimes classified in the Plantae Kingdom and sometimes in the Protista Kingdom. Algae is very important even in today's world as they carry out one half of all photosynthesis. They, therefore, provide the Earth with much of its oxygen. They are also an important part of the aquatic food web.
Dinoflagellates are microscopic algae of a reddish-brown color. They were asymmetric and were the first organism protected by a woody substance. It was much like the cellulose in plants today. They live in warm coastal waters. They are the cause of the red tides.
Phylum: Cnidaria (coelenterate)
The hydra is the most advanced organism of this period. The hydra is a carnivore that uses its tentacles to capture its prey and then pushes it into its mouth. Its mouth is also its anus. They can reproduce by asexual budding and sexually.
Although there are no fossils of this soft bodied animal, scientist are sure it lived during this time. The euglena has an "eye" that detects light. It is both an animal and a plant which is why it is in the Kingdom Protista. It can use sunlight to make food by photosynthesis like a plant and can eat small particles of food from the water like an animal. It is still lives on Earth in murky pond water.
Phylum: Ciliophora (cilia)
A one celled microscopic organism that scientists believe lived in the Earth's first seas. It has thousands of tiny hairs on its body to help it move. They are called cilia. It can move very quickly. The paramecium has survived for the whole history of Earth.
Phylum: Actinopoda (ray feet)
We know that radiolarians lived in Earth's early seas, because they have a beautiful shell with needlelike projections. When they died, their shells left imprints in rocks. We now can study the fossils of these creatures.
Phylum: Forams (porous shell)
Foraminifers are microscopic organisms. They had shells so we can study their fossils. They had a foot like structure that projected through tiny holes in their shell.
Phylum: Rhizopoda( actively seek food)
A single celled organism that scientists think lived during this era. It moves by pseudopod (false feet). It moves slowly and surrounds its food until the food is inside its body. It left no fossils as it is a soft bodied organism.
Bacteria that lives on the dead matter of other animals. They reproduce by simply splitting in two. Bacteria were the biginning of all the future life on Earth. Cyanobacteria produced the oxygen in our atmosphere.
Phylum: Chlorophyta (green)
A group of blue-green algae. Today, this algae lives in fresh water.
Phylum: Rhodophyta: (red)
Rhodophyceae are many celled red algae. Their fossils provide the earliest record of life on Earth as some of the forms have shells. Relatives of these live on today. They had a stem, a kind of root and branches. They live in warm marine water.
Phylum: Phaeophyta (dusky )
Phaeophytes are a kind of brown algae. They left fossils we can study. The fossils look like they are related to the rockweeds we find in today's oceans. They live in cool marine water.
This period is named after Cambrian (the Latin name for Wales) because the first fossils from this time were found in Wales. This period began at the end of the great ice age over 550 million years ago. The climate was mild and all life still lived in the sea. There was a great explosion of life during this period. Many of the organisms found on Earth today appeared during this period. There were some very large, though still simple invertebrates.
These were microscopic organisms that varied greatly in size and shape. They all had one or more long, hair-like threads called flagella. They used the flagella to move. They are now divided into several different phylums.
Volvox are beautiful hollow, green spheres. They rotated as they swam. They were really many one celled algae in a colony. They each had two flagella that moved the mass through the water. The Volvox had chlorophyll like a plant, but moved about like an animal.
The Vauxia was a type of sponge. Its skeleton was made of silica, a substance found in sand. They were also one celled animals that lived in a colony.
The Kutorgina is another Lophophorate. It could not move and its shell is usually attached to hard surfaces like rocks.
Phylum: Cnidaria (coelenterata)
Streptelasma were one of the earliest corals. They lived in warm, shallow water. They had tentacles to capture their food. They are called flower animals. Coral secrete shells of calcium and live in shallow water in colonies.
Jellyfish and Sea Anemone
Phylum: Cnidaria (coelenterata)
Jellyfish and sea anemone are coelenterates, a word that means hollow intestine. They have their mouths under their bodies and reproduce sexually. Jellyfish are a member of the class: scyphozoa. They all sting their prey with tentacles. Sea anemone are a member of the class: anthozoa. They have a radial design and can detect its enemies from all sides.
Phylum: Bryozoa (moss animal)
A Rophophoratus, an animal that lived in a colony of tubes. A tiny animal with tentacles lived in each tube, they were similar to the coral, but they had developed a 'u' shaped digestive system that had an anus.
Eocrinoids resemble modern day sea lilies. They had five arms called brachioles. They filled the seas during this period.
The Aysheaia was a creature like a worm and like an arthropod. It had 20 unjointed legs. It had two horns on its head which may have emitted a liquid that smelled to scare off predators.
Cystoids were echinoderms that looked like plants. They were anchored to the ground and had arms that waved back and forth to get their food from the water. They came at the end of this period.
Sea Cucumber and Sea Anemone
Sea urchins and sea cucumbers have prickly skin. The sea urchin is in the class: echinodea while the sea cucumber is in the class: holothuridea. The sea cucumber has five rows of tube feet. They have changed very little in 600 million years.
Scenella and Proplina
The Scenella was an early Molluska the class: bivalvia. It had an uncoiled shell. The Proplina, class: gastropoda, developed late in the period and had a slightly coiled shell. Snails have a wide muscular foot, a head with eyes, a mouth, and tentacles. They live in a shell for protection.
The algae evolved into huge colonies called seaweed. A large brown algae called kelp could reach 600 feet long. Algae lives in coastal water.
Two thirds of all life in the Cambrian sea were trilobites. They were arthropods because they had jointed feet. Trilobites means three lobes. All trilobites had three segments. These segments ran lengthwise down its body. The Olenellus was the first fossil to be discovered. The Dikelocephalus was six inches long. The Aglaspis had a head like a horseshoe crab, 11 pairs of legs and a long tail. The Paradoxides was 10 inches long. It had a small tail.
Sidneyia and Marrella
Phylum: Molluska or Arthropoda
The Marrella had 2 pairs of fuzzy antennae, large spines and legs with gills. Scientists are not sure if they are arthropods or early crustaceans.
This period started about 500 million years ago. It lasted about 75 million years. The fossils of this period were also found in Wales in the land of Ordovices. There were many, many kinds of seaweed, mostly made of green algae and Protists. These tiny shelled animals left huge deposits of shells when they died. They provide the world today with rich deposits petroleum.
Phylum: Forminifera (open tubes), Actinopoda (ray feet)
There are huge deposits of these tiny shelled animals. Phylum: Foraminifera (animals with open tubes) were Triticites, Globigerina, Camerina, and Dentalina. An example of Phylum: Actinopoda: ( ray feet) was the Heliosphaera, which looked like a spiny ball and the Actinomma which looked like the modern day sea urchin.
Phylum: Cnidaria (coelenterata)
The Streptelasma became even more common. There were many other varieties of horn shaped corals as well.
The Hemicystite was another echinoderm that resembled the modern day sand dollar, class: echinoidea. It had five rows of tube feet and muscles for movement. There was also a primitive starfish class: asteroidea, with short stubby legs called the Hudsonaster.
The crinoids and cystoids filled the seas. It is often called the Age of Sea Lilies. Thousands of these animals lived together on the banks of the ocean. They had a calyx or hard shell that protected the animal. The crinoid clung tightly to rocks. When it was hungry, it waved its arms and the water rushed into its mouth. When its mouth was full, it swallowed. The crinoids helped to purify the water as the absorbed great amounts of calcium from the water. When they died, their bodies fell to the bottom of the sea and created deposits of limestone.
The Hughmilleria was a small, 3 to 10 inch, sea scorpion. Their modern day relative is the horseshoe crab.
The Rafinesquina is another Lophophorate that only lived in the Ordovician seas. We do not know why it disappeared.
Another mollusk, class: cephalopoda, appeared in this period. Cephalopoda means head foot as these animals had its head attached directly its foot. They had external shells and often grew to enormous size. The Endoceras was 12 feet in length. It had stony deposits in its cone shaped shell to keep the animal from floating.
Another snail, class: gastropoda, the Maclurites appeared. The Cycloneman was a small snail that often attached itself the crinoids where they were sure to find food. Many bivalved mollusks like the Byssonychia, (class: bivalvia) now appeared. These animals have two shells that are joined together by a valve. It had a hatchet shaped foot that it used to move. It had a rasping tongue to feed with and gills to take in oxygen.
The trilobite had now developed an interesting ability. The Flexicalymene could curl up when in danger. The trilobites were now slowly declining.
This period was named after an ancient tribe, the Silurians that once lived in Wales. It began 430 million years ago. Volcanic eruptions and earthquakes made this a violent period for life. Shallow seas were created when changes in the water levels occurred. These shallow areas had large quantities of corrals and algae that formed reefs. As the seas retreated and then returned, great muddy areas were repeatedly exposed to sun and air. Some of the plants that thrived in the oceans adapted to this new life on land. The first vertebrate, an ancient fish appeared.
During the Silurian Period Africa and South America were at the South Pole. North America and parts of Europe sat on the equator. The climate was very humid and plants flourished releasing lots of oxygen into the atmosphere. The ozone layer formed which protected the Earth from the sun's harmful rays.
The Psilophyton was one of the first plants to live on land. These plants would eventually change the face of the land. Psilophytae have no leaves or roots and are sometimes called naked plants. They have to depend on water as they have no vascular system. The Whiskfern or Psilotum is a modern day Psilophyton but it is now classified as a trimerophyte.
The Bryophytes were the mosses, liverworts and hornworts but modern day classification includes only the mosses. They made two adaptations that made it possible to move onto land; they have a waxy cuticle that helps them retain water and protected embryos. They had to live near water, though, and as they lack a woody stem, they are usually only 1 - 2 cm. tall.
Spiral Shell Snails
The Murchisonia and Platyostoma had true spiral shells.
The largest arthropod of the Paleozoic Era, was the Pterygotus. It was a giant sea scorpion that grew to 10 feet in length. It ate everything. It loved to eat trilobites. It also ate the armored fish. Its jaws could rip through even the toughest armor shell. They are believed to be the early ancestors of today's land scorpions.
The Goniophora, class: bivalvia, appeared. It was bivalved, meaning its two shells were of equal size. It was an ancient ancestor of the clam. The Dentalium, class:gastropoda, was a snail like creature whose shell was shaped like an elephant's tusk. The Platyceras was another small snail that lived near the crinoids to be sure to find food.
Dalmanite was a common trilobite of this period. The extinction of the trilobites may have been due to carnivorous fish and larger arthropods.
Myriapod was an early arthropod. It had an exoskeleton, one pair of antennae and a pair of legs on each body segment. It looked much like today's millipedes. Although the number of trilobites were declining, there were still some around.
Kingdom : Animalia
The first fish were small and jawless and had heavy armor. The Cephalaspis, class: Agnatha, had a flat head that was round in the front and had horn - like projections that were pointed to the back. It looked a lot like a trilobite. Its two eyes were on one side of its head and it had one nostril and a dorsal fin to help it to balance.
The Berkenia had a more narrow shape. It was covered by scales. It had ventral fins and its eyes were on the sides of its head. They ate tiny soft bodied animals that lived in the muddy bottoms of river beds and lakes.
The Devonian Period began about 345 million years ago. The name comes from Devon, England where the first fossils were found. Plants continued to thrive on land. It was an important time of rapid change and growth for plant life. By the end of this period, there were jungles of ferns. Life was difficult as the swampy areas where much life was found often dried up as the seas receded. This led to the extinction of many animals. Many fish died, but some made an amazing adaptation. When the water in their pond dried out, they used their short fins to push themselves to ponds where there was water. They also developed primitive lungs that could store oxygen they gulped from the air. This changed the course of life on Earth forever as land animals began the take over of the land. The Devonian Period is often called the Age of Fishes.
During the Devonian Period volcanoes erupted in what is now Greenland, Western Canada and Russia. The water of the sea warmed up and contained less oxygen.
Phylum: Cnidarians (Coelenterates)
The corals loved the shallow seas of the Devonian Period. They formed so many islands that scientists often call this the Age of Corals. Corals like the Caninia, Blothrophyllum and the larger Siphonophrentis were abundant in the shallow seas.
Plants had a difficult time adapting to life on land. The swamps often dried up turning lush swamps into deserts. Then the land would flood again and the plants would again flourish. The Rhynia and Asteroxylon were plants that lived in this period. They were spore bearing plants that had no roots, but they did have
primitive leaves attached to the stem.
The Brittle Star, class: Ophiurordea, was a spiny echinoderm whose arms easily broke off. The modern day echinoderms can grow an arm back to replace any that break. They had tiny tube like feet that moved food to its mouth.
Spiny trilobites continued to flourish. Terataspis grew to about 20 inches, while the Ceratarges was only at most 2 inches. There were many other arthropods as well. They probably crawled on the bottom of the ocean floor.
Some fish developed lungs and bony skeletons so that they could breathe and move when the ponds dried up. These fish had fins that looked like lobes and are often called lobe-finned fish. Dipterus and Scaumenacia, class: osteichthyes, were early lungfish. These lobe finned fish could take in oxygen into primitive lungs when their ponds dried out. Their descendants tend to live in fresh water. There were also fish whose fins stretched over bony rays. The Cheirolepis, was a primitive ray-finned fish. It had a skeleton made of cartilage except for its bony head. It grew to about 2 feet. The ray-finned fish of today are the most diversified vertebrates. They live mostly in marine environments. These fish would soon dominate the waters.
The Gigantoceras, class: cephalopoda, was a nautilus that lived in this period. The nautilus is the only cephalopoda that has a shell it lives in for protection. The shell is heavy, so it has the ability to emit internal gases to give the shell buoyancy in the water. It was very strong and had long, tentacles that it held its prey with. It could emit a dark liquid that clouded the water so that its predators could not follow it.
Air breathing land snails appeared. These are the only mollusks from the class gastropoda to live on land. Snails without shells, the slugs also developed.
Early fish like Anglaspis, class: agnatha, had developed armor to help provide protection from the sea scorpions, but it was not enough. The Eurypterids had plier like jaws that could get through the toughest armor. The Dinichthys, (terrible fish) class: placoderm, grew to 30 feet. It developed paired fins to swim faster, but its heavy armor still got in the way. It hid in the sea weeds and waited for other smaller fish to swim by. It caught its victims with hinged jaws like a snake and sharp teeth. The fish had to become faster swimmers to survive.
Cladoselache, class: chondrichthyes, was a fish much like the present day shark. It had no armor, but had internal cartilage. It had broad fins, grew to be 2 to 4 feet long, and was the fastest swimmer of the Devonian Period. Pleuracanthus was another primitive shark that grew to about 8 feet long. It had a long spine on the back of its head.
The Carboniferous Period began 300 million years ago and lasted 40 million years. It is named after carbon which is the main element in coal. Periods of rain and draught continued and the seas advanced and retreated many times. There were huge jungles and swamps.
The end of the period brought a drastic changes. Huge forests died out completely and another ice age began. Ice covered the Earth almost to the equator. Coal formed where the forests were buried under deep layers of mud. This period is divided into two sections: The Mississippian during which amphibians first appeared on land, and the Pennsylvanian in which primitive reptiles appeared. This age is called the Age of Coal, the Age of Amphibians, and the Age of insects.
Seed ferns also appeared. Ferns, like the Neuropteris, reproduced by seeds. Their seeds were the size of nuts. These ferns no longer needed water to reproduce. Their seeds were fertilized by wind-blown pollen. The modern flowers may be descendants of the seed ferns.
Thousands of insects, class: insecta appeared and they swarmed through the forests. The first insects were tiny and wingless. Today, the springtails and silverfish, still exist. Later insects with flaps on their backs appeared. They were the forerunners of winged insects. The Stenodictya, had both flaps and true wings. It is considered the first insect to develop true wings. These wings helped the insects to escape their predators, but they also got in the way. Termites also appeared. Meganeuropsis was a giant insect that looked like today's dragonfly. It grew 15 inches in length and had wings 30 inches wide! The cockroach also appeared. It had wings that could be folded away. This helped the insects to hide on land. Some cockroaches grew to be 4 inches long. Architarbus was a primitive spider about 3 inches long.
Conifers, like Lebachia, appeared. Its leaves were needle like, much like the Norfolk Pine. The seeds were not yet in cones, however. These plants were more able to survive the drier climates that were to come.
Lycopods continued to flourish. Lycopoda means wolf claw in Greek. The plants had roots that were shaped like the claws of a wolf. Most of the plants were actually trees. The Lepidodendron grew 100 - 125 feet in height and 4 - 6 feet around. The leaves formed a spiral pattern around its trunk. The Sigillaria was a smaller tree. Its leaves looked like blades of grass. It reproduced by spores. Modern day lycopods are the club mosses.
Phylums: Sphenophyta,Coniferaphyta, Pterophyta, Cycadophyta
The plants of this era could not depend on water for their survival. Only plants that could survive long periods of draught with torrential rains survived. They were cycads, conifers and horsetails. One seed fern survived, the Glossopteris . Its leaves were shaped like giant human tongues.
Calamites and today's Horsetails were simple vascular plants. They had true roots, hollow, jointed stems and whorls of small leaves, but still needed water to reproduce. They grew to be 40 feet in height. Horsetails are sometimes called scouring rushes as they were once used to scrub pots and pans.
The Amphicentrum, class: osterochthyes, is an example of another ray-finned fish. It grew to be about 6 inches long and lived in quiet water. The ray finned fish fish became very plentiful. The lobe-finned fish were declining, but they were the ones that evolved into amphibians. There were two kinds. Although the lungfish could gulp air to survive when its pond disappeared, it was the fringe-finned fish that could use its sturdier fins like stubby legs to reach another pond.
Mesosurus, class: reptilla, was a water living reptile that lived at the end of this period. It had a trim body and its large back feet were well adapted for swimming. It had a long snout and sharp, needle-like teeth. It probably lived on fish.
The Ichthyostega, class: amphibia, was one of the first amphibians. It was a heavy four legged creature 3 -4 feet long. Its skin still had scales and it still spent most of its time in the water. The water was its source of food and was where the amphibians laid their eggs.
The Diplovertebron was a very small primitive amphibian with very weak legs.
Eogyrinus or Pteroplax was a huge salamander that grew to be 15 feet long. It lived in swampy areas and ate fish and other, smaller amphibians. It had almost useless legs that barely reached the ground. It wiggled through the water like snake.
Diplocaulus was an unusual amphibian. It had miniature legs and a skull shaped like an arrowhead. It breathed with gills and probably lived at the bottom of lakes.
Mesozoic comes form the Greek word meso or middle and zoic or life. Life now moved onto land following the plants and insects which prepared the soil and provided food. An atmosphere also appeared. This is the Age of the Dinosaurs.
The first fossils from this period were found in Perm, a Russian province near the Ural Mountains. This period lasted about 50 million years. There were great changes during this period. Volcanoes erupted, the great swamps dried up and turned to land and then to mountains. The Appalachians and Ural mountains were formed. There was another ice age. The seas retreated leaving great salt deposits behind. Many plants and animals became extinct as the temperature drastically changed. The great ferns that had depended on water to survive died out. The trilobites and armored fish also neared extinction. As the Permian Period became drier and hotter, it became more and more advantageous for the animals to adapt to life out of the water. Reptiles slowly came to the forefront.
Insects started an go through an incomplete metamorphosis of change. They went through three stages - the egg, nymph and adult. The nymphs are very much like the adult insects. They depend on the same environment as the adult. The cockroach goes through an incomplete metamorphosis today. Other insects went through complete metamorphosis. It has four stages: the egg, larva, pupa and adult. The larva and adult live completely different lives. Ninety percent of all of today's insect go through complete metamorphosis.
There were many, many amphibians. Eryops, class amphibia, was a giant amphibian that grew to 6 feet long. It had short, strong legs and leathery skin. It probably swam in the water and rested on shore waiting for dinner to show up.
The Miobatrachus was a tiny amphibian that was only about 3 inches long. Its head was long, wide and blunt and it had large eyes. Its hind legs were longer than the front legs and it had a long, sturdy tail.
The Cyclotosaurus was the largest amphibian to ever live. It grew to 15 feet. They were all still very dependent on water.
The Seymouris' skeleton looks like both the amphibian and the reptile. It had a thick body, a massive head. It probably was carnivorous and ate other small amphibians and large cockroaches.
The Glossopteris was one of the only seed ferns to survive the ice and drought of the Carboniferous Period. It spread from Siberia to the North and South Hemispheres. Its leaves were shaped like human tongues.
The Hylonomus, class: reptila was the first true reptile. It was only 1 foot long and is related to modern day turtles. Reptiles were better suited to the hot, dry climate of the Permian Period.
The Labidosaurus was another primitive reptile. The Dimetrodon was a fierce, carnivorous reptile that grew up to 11 feet long. Paleontologists do not know why he had a large sail. They do know it was not used to swim as it was a land animal. It may have been a primitive means of cooling its body temperature. All reptiles are cold blooded which means they cannot control their body temperature.
The Dimetrodon had very unusual teeth. They had canines like a dog. Most reptiles have teeth all the same size. Scientists wonder if the Dimetrodon were a link to the mammals.
The Cynognathus also had flesh tearing canine teeth. It had a large head with a small brain. Its sturdy legs could keep its body well off the ground. This allowed it to rapidly pursue prey or to quickly scurry away from its enemies.
The Eryon, class: crustaceans, was the first lobster like arthropod. It was 4 inches wide and 4 inches long and shed its shell as it grew.
The Permian Period was very dry. Many of the great forests which were dependent on water died out in great numbers. Conifers, Horsetails and Cycads took over. Cycadophyta look like palm trees, but they do not flower. It has cones like a conifer
The Triassic Period began about 220 million years ago. It marked the beginning of the Mesozoic Era. Mesozoic means middle life. It is named after the three layer formation of the rocks found at this time. The super continent, Pangea was in the process of breaking up. There were now three continents. Many volcanoes continued to erupt. Many amphibians died as the hot, dry weather continued. The reptiles continued to flourish.
The plants of the Triassic Period continued to flourish. A new cycad, the Cycadeoidea, looked like a small palm tree with a short stubby trunk. The trunk was very colorful. It was so prevalent that the Jurassic Period is sometimes called the Age of Cycads.
The Proganochelys was the first sea turtle. It had a horny beak, but no teeth. Since it could not pull its head or tail into its shell, they had sharp spines for protection. These vertebrates have the longest life span of any vertebrates.
The Cymbospondylus, class: retilia, was a sea reptile. It was also called, Ichthyosaur or sea lizard. It had a long slender body with fin-like flippers and a strong tail. It surfaced to breathe in oxygen with its lungs. Its skin was darkly colored above and lighter below like a shark. They hunted fish, squid and belemnoids.
The Ammonoid, class: cephalopoda, was a nautilus. There shells were whorled like a ram's horns. Their shells grew very varied and elaborate. Many ammonites could withdraw entirely into their shell. Some were crawlers and some were swimmers.
The Belemnoids, class: cephalopoda, had shells so small that their mantle covered it. Without heavy external shells, they were fast swimmers.
Dinosaur means 'terrible lizards. There were many more plant eating or herbivore dinosaurs than terrible carnivores, however. The first dinosaurs were the thecodonts or socket teeth. Ornithischians, bird hips, had hipbones like those of a bird and saurischians, lizard hips, had the same hipbone structures of the original thecodonts. Ornithosuchus was 6 feet in length. It had long, slender limbs and a sturdy tail that it used for balance. It had one large toe and two small ones on the sides. It was a carnivore and ate smaller herbivore dinosaurs.
Plateosaurus was 21 feet in length, most of which were its head and tail. It had a small head and blunt teeth for chewing plants. It lived in the lush swampy lowlands. It was an ancestor of the sauropods, or dinosaurs that walked on four legs.
Kannemeyeria had a large, knobby head. It was 6 feet in length and was a relative of the Dimetrodon.
Conifers were very abundant along with the cycads, which looked like palm trees. They lived primarily on the plateaus.
Ferns and horsetails lived on the lowlands closer to the lakes and rivers.
The Ginkgo tree appeared. It is a softwood tree and still lives today. It has fan like leaves that turn gold and drop off in the winter. It is very hearty
and can survive where pollution is found.
The Jurassic Period began 190 million years ago. It is named after the Jura Mountains in France. The climate slowly became tropical and humid again. Swamps, lakes and streams reappeared. Thick forests grew which could support a lot of animal life. The reptiles grew to amazing sizes. The Jurassic Period is most famous for the great variety of dinosaurs that invaded all available environments.
The Aeger, class: crustacean, was a common creature that looked a lot like the modern day shrimp. I had 10 legs and long antennae. Today all crustaceans have 2 pairs of antennae.
The forelegs of climbing reptiles slowly evolved into wings. Pterosaurs, winged lizards, were small lizards with huge wings. Their wings were like the bats of today's world as they did not fold back easily. They probably lived in high cliffs where they would be safe from predators and could easily take off into the air. They had very large eyes, which meant this was probably important to their survival. They would swoop down over the water and scoop up fish or small sea animals with their sharp, long teeth. If they had to land in the water, however, they would not be able to take off again. They would drown or be eaten.
Pterodactylus, wing finger, was another flying reptile. It had developed hollow bones like a bird, so it was lighter. It flew by gliding, however, and probably only went short distances. Its wing had bones that resembled an arm, wrist and one very long finger. It did not have as many teeth.
Rhamphorhynchus was another flying reptile with a very long wingspan. Its tail had a flap of skin on the end that could be used for steering.
The Archaeopteryx, class: aves, had teeth, a long bony tail, solid bones and sharp teeth. It also was covered in feathers. It was about the size of a crow with a wingspan of about 2 feet. On each wing were three fingers with claws, probably used for climbing trees. Its muscles were too weak for it to be much of a flyer, so it probably glided most of the time.
Ichthyosaurus, class: reptilia, was an aquatic reptile. It resembled a porpoise with its flippers, fish-like tail and dorsal fin. It was 24 feet in length, had no gills and breathed air through its nostrils. It never went on land and gave birth to live young in the water.
Plesiosaurus, more like a lizard, lived on land and then moved back into the water. Life in the water is easier as the climate affect is less and it is much easier to support a heavy weight. It had a long snakelike neck and a small head. It ate fish and other sea creatures. It had large paddle-like flippers that they used like oars to row forward and backward. It grew 10 to 20 feet long. It may have laid eggs on land.
Stegosaurus, plate lizard, was an armored dinosaur. Although its back was well protected by its bony plate, its sides were unprotected and vulnerable to the many carnivores that lived. It was about 20 feet long, had a small head and weak jaws. Its tail had its own brain that was controlled by its hind legs. This brain was 20 times bigger than the brain in its head.
Brachiosaurus was 80 feet long. It could stretch its neck 40 feet into the air. It was the one of the heaviest dinosaurs to live on Earth, weighing 85 tons. It had a very tiny brain weighing only 7 ounces. It had to spend most of its time eating to feed its huge body.
Morganucodon, class: mammalia, was the earliest known mammal. It had hair, warm blood and suckled their young with milk. It was a small rat-like creature that ate dinosaur eggs, insects and other small invertebrates.
The Cretaceous Period began about 130 million years ago. Cretaceous means chalk and their were a lot of rocks containing chalk found in this period. There was again a lot of volcanic activity. The Rocky Mountains, the Andes Mountains and the mountains of Antarctica and Northeast Asia were formed. By the end of the Cretaceous Period the continents looked pretty much as they do now. The climate, however continued to be mild and warm and plants and animals continued to flourish. This period is often called the Age of Dinosaurs. The dinosaurs dominated the Earth until the end of this period and then they mysteriously disappeared. Scientists have many theories as to why, but so far, no one knows for sure why they died.
During the Cretaceous Period South America drifted away from Africa. The Atlantic Ocean widened and the climate cooled.
Trees resembling the walnut, oak, elm, maple and magnolia developed. The first flowering plant appeared and there were many smaller bushes and shrubs. These provided better protection to the animals that lived on the ground. The Viburnum was a plant that resembled today's honeysuckle. The Earth was now colorful.
Argyrolagus, class: mammalia, was a small marsupial. It had a pouch that its babies could suckle in while growing. It looked like a modern day Jerboa. It had large feet for jumping, large ears and a very long tail.
Oxyaena was a carnivorous, placental mammal. Its babies developed totally inside the female. Its short legs had hoofs and it was about 3 feet long. It was not very smart, though, as it had a very small brain.
Ankylosaurus was an armored dinosaur that was 17 feet long. It had sharp, pointed spines on its sides and a club-like tail to protect itself. It had very soft teeth so it could only eat plants. It also had hoofed feet.
The seas were full of mollusks. Clams and oysters developed in great quantities. Gryphaea, an oyster, lived on its left side and it could open and close its shell. Some mollusk could now detach themselves from their shell and look for a new home. The ammonoids became extinct.
Tyrannosaurus rex, king of the tyrant lizards, was the largest carnivore to ever live. It stood 18 feet high and was 45 feet long. It weighed 9 tons. It walked on two enormous legs with a long, powerful tail to help it to balance. The claws on its hind feet were 4 inches long. Tyrannosaurus rex could tear open and crush the bones of the largest herbivores. It had tiny, useless front arms and it could not run very fast.
Triceratops, three horned lizard, was well prepared for battle. It had two 40 inch long horns over it eyes. It was very ferocious if attacked. Triceratops had a horny beak and ate plants.
The dinosaurs, class: reptilia continued to dominate the land, sea and air. Pteranodon was a flying reptile. It was one of the largest animals ever to fly. Its wings measured 30 feet long. Pteranodon had a beak without teeth and a bony crest on its head. It had a pouch under its beak to carry the food it scooped out of the sea, like modern day pelicans do.
Tylosaurus was a lizard that lived in the sea. It had broad, webbed feet and a powerful tail. Tylosaurus had teeth that replaced themselves like the modern day sharks. Its jaws were also double hinged like a snake so that it could open wide to swallow its food.
Diplodicus, double beam, was enormous. It weighed 20 tons and was 90 feet long. It hung out in the water where some of its weight would be supported. Diplodicus could nibble plants on the water's floor and reach up to breathe with its nostril on the top of its head. It had a very tiny brain.
Hadrosaurs, or duckbills lived during this period. They had teeth in their beaks and although they had webbed feet, they walked upright. They had large hollow horns on their heads that may have been used to store oxygen or may have been used as horns. Parasaurolophus was a duckbill dinosaur.
Cenozoic comes form the Greek word Ceno or recent and zoic or life. Plants now covered the land and flowers appeared. The dinosaurs were now extinct and the time was right for mammals to take over the land. The first mammals were small just as the first life in the sea was small, but soon mammals too grew large and fearsome.
The Tertiary Period marks the beginning of the Cenozoic Era, recent life. The Tertiary Period began 65 million years ago. Europe and Asia were separated as they are now, but a land bridge continued to exist, probably where the Bering Strait is now. There were vast volcanic eruptions all over North America which accounts for the volcanic, igneous, rock still to be found. The Himalayas and Alps were formed, as well as the peaks, Mt. Shasta, Mt. Hood, Lassen Peak and Mt. Ranier. The climate was still warm and tropical until the very end when cool winds began to hint at the coming ice age. This period is called The Age of Mammals.
During the Tertiary Period volcanoes between North America and South America built up the Isthmus of Panama. Meat eating mammals of North America crossed the new land bridge into South America. They wiped out all but a few of South America's marsupials. Today, only the opossum survives. Antarctica slid to where it is today and began to ice over.
Buckthron and Katsura
The Tertiary Period was warm and humid. Tropical and subtropical climates were found as far north as Canada. The woods were full of ferns, palm tree and fruit trees. The Buckthron and Katsura were two very common trees.
Diatryma, class: aves, was a flightless bird. It had very small wings and a huge body with no tail. It could walk and run on its study legs. It had a large, curved beak for eating plants and small mammals and reptiles
Basilosaurus was a marine mammal. It was an early whale. It had a short snout, saw-like teeth and nostrils high on its head. It had front flippers and a long tail with flukes so it could dive up and down. It had very tiny back legs that were useless. They also developed blubber to keep in their body heat.
Procoptodon, great beast, class: mammalia, was a huge marsupial. It had a catlike face. It was an early relative of today's kangaroo.
Megatherium was a large ground sloth. It was 20 feet long and weighed 10,000 pounds. It carried its weight on its turned in feet which made its movements look clumsy. Megatherium had strong, clawed forelegs it could use to pull down branches. It peeled off leaves with its long tongue. It could sit upright on its hind legs like a bear.
Alticamelus was a giraffe-like mammal. It was a herbivore, that had nails with large pads instead of hoofed feet. This allowed it to run better on the grassy plains. It grazed by pulling up grass in its toothless, upper front gums and lower incisor teeth.
Uintatherium was a huge herbivore that was 12 feet long. Like most herbivores of this period it had hoofed feet. It also had three pairs of skin covered bony horns and long, canine tusks curved downwards from its jaw. It was not very smart as it had a very small brain.
Coryphodon looked much like modern day pygmy hippos. It grew to about 8 feet long and had elephant like feet. It had canine tusks that the males used for fighting. They lived near water and probably also used their tusks to pull up plants.
Moeritherium is a modern day relative of a group of mammals that had long noses and tusks, like the elephant. It grew to about 5 feet long and 2 feet high.
Notharctus is an example of early primates. It looked a lot like present day lemurs and it was probably nocturnal. Primates had their eyes at the front of their head so the two pictures their brain received overlapped to make one picture. It also had typical hands with a thumb separate from the rest of its toes. It also had a long prehensile tail which helped it swing through the trees.
Paleomastodon was a descendent of Moeritherium. A short trunk and tusks of the upper and lower jaw had developed. The lower tusks were flat for scooping out plants from swampy water. They were 3 to 6 feet tall and weighted up to 2 tons.
Hyracotherium was originally thought to be a descendent of the rabbit, but is now known to be an early horse. It had an arched spine and its back legs were like the rabbit. It had 4 toes on its front feet and 3 on its back.
The Quaternary Period is the only period of the Neozoic Era. It began about 3 million years ago and still continues today. Neozoic means new life and refers to the highly developed plants and animals that exist today. There were four separate ice ages with interglacial periods of warmer temperatures. The Earth may be in an interglacial period now. The volcanic activity of this time formed the Cascade Mountains. The peaks were than worn and sharpened by the advancing glaciers. Great lakes were created by the glaciers: Lake Bonneville filled the western part of the United States and is now called The Great Salt Lake. Many animals migrated to Africa and South America where the temperatures were warmer. They still live there today.
Pliohippusclass: mammalia, is the closest relative of the modern day horse. Its legs and feet were now better adapted to running, and its teeth were better suited for eating grass. It was the first one toed horse, and really differed from modern horses in size only.
Smiloson had dagger-like canines and powerful jaws. It hid by water holes where it preyed on herbivores that came to drink.
The woolly mammoth lived in the frigid northern climate. It grew to 10 feet tall at the shoulder, and its front legs were longer than the back legs. It roamed in herds and hunting by early humans almost certainly led to its extinction.
Ramapithecus emerged at the end of the Tertiary Period. It lived in the trees and ate mostly plants, nuts, fruits and seeds. It did have frontal vision, hands with opposable thumbs, social patterns and a higher intelligence. The world was again changed forever by the arrival of humans.
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Language Cards for Classification
When I introduce a vertebrate, I first ask the students what they know. They can usually tell me most of the pertinent details and I expand and add as needed. Then I show them the external and internal parts work.
I then ask them to name some of the vertebrates that they know. If one says Trout for a fish then I begin by saying the Kingdom of all animals is Animalia and lay out that card - traditionally in red. I say that since they are vertebrates they are in the phylum Chordata or Vertebrata - this card is also traditionally in red. I have done the fish in ocean blue, amphibians in green, reptiles in brown, birds in sky blue and mammals in dark red. Then I tell them that a Trout is a bony fish and is classified in the class Osteicthyes. I then call on another person. When the three kinds of fish have been named - you may have to give them a hint for jawless - "Does anyone have an aquarium at home? Remember that strange fish that sucks on the glass with its mouth?" Then we all pretend to be jawless fish and it becomes a favorite.
I do this with every Class. The students quickly try to think of as many different animals as they can. I do not have all the classes of birds and mammals, as they are way too numerous. Just tell the student that they can find that out for you. Be sure to have a really good resource book like Latin Names made easy and I have a large mammal encyclopedia in my room that is always being used. It is really too hard for most to read on their own, but we manage somehow. Most of my students research by class rather than by animal. Their report then starts with the reason why all the animals are classified together. They may do one animal in detail and the rest briefly or they may do every animal in detail with partners splitting up the work.
Phylum: Chordata (Vertebrata)
Class: Agnatha (72 species) Jawless Fish
Class: Chondrichthyes (711 species) Cartilaginous Fish
Class: Osteichthyes ( 20,730 species) Bony Fish
Class: Amphibians (4,000 species)
Order: Urodeles (tailed one) (400 species) Salamanders & newts
Order: Anuans (tailess ones) (3,500 species) Frogs & toads
Order: Apodans (legless) (150 species) Caecilians
Class: Reptilia (7,000 species)
Order: Chelonia (244 species) Turtles
Order: Crocodilian (22 species)Alligators & crocodiles
Order: Squamata (6,300 species) Lizards & snakes
Order: Rhyncocephalia (1 specie) Tuatara
Class: Aves (Birds) (8,600 species)
Order: Piciformes (378 species) Woodpeckers, toucans
Order: Passeriform (perching) (5,206 species)
Order: Apodiformes (389 species) Hummingbirds, swifts
Order: Psittaciformes (328 species) Parrots, lories, cockatoos
Order: Columbiformes (300 species) Pigeons & doves
Order: Struthioniformes (1 species) Ostrich
Order: Rheiformes (2 species) Rheas
Order: Casuariformes (4 species) Emu, cassowaries
Order: Spenisciformes (16 species) Penguins
Order: Strigiformes (133 species) Owls
Order: Falconiformes (286 species) Birds of prey
Order: Coliformes (6 species) Mousebirds
Class: Mammals (4,500 species)
Order: Monotremes (egg laying) (3 species)
Order: Marsupials (pouch) (270 species)
Order: Insectivora (345 species)
Order: Chiroptera (960 species) Bats
Order: Carnivora (230 species)
Order: Cetacea (76 species) Whales, dolphins
Order: Rodentia (1,700 species)
Order: Edentates (29 species) Anteaters, sloths, armadillos
Order: Lagomorpha (58 species) Pikas, hares, rabbits
Order: Pinnipedia (34 species) Seals, sea lions
Order: Primate (183 species)
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Resources Time Line of Life
Big Picture Science
Raptor Red (to be read to students with editing - wonderful!)
Robert T Bakke
ISBN 0553 101 24
Ultimate Book of Dinosaurs
Katie Orchard - editor
ISBN 0 75500 046 3
From Lava to Life
ISBN 1 584690 42 9
Dinosaurs to Dodos: An Encyclopedia of Extinct Animals
ISBN 0 590 31684 2
How to Draw Dinosaurs
Georgene Griffin - illustrator
ISBN 156156 5733
ISBN 0 7922 72196
Encyclopedia of Dinosaurs
Dr. Douglas Palmer
Simon & Schuster
ISBN 0 684 864118
Jane Chisholm - editor
ISBN 0 7460 27583
Jim Bailey Tony Seddon
Oxford University Press
ISBN 0 19521 444 7
Atlas of the Prehistoric World
ISBN 1 56331 829 6
Doris Kindersley Inc.
ISBN 1 56458 2299
Thunder Bay Press
ISBN 1 85028 262 5
Fossils: Science Nature Guide
Thunder Bay Press
Jill Bailey and Tony Seddon
Oxford University Press
The Extraordinary Story of Life on Earth
Angela, Piero and Alberto
Life Story (A MUST!!!)
Virginia Lee Burton
Houghton Mifflin and Co
The Evolution Book (A MUST!!!)
Workman Publishing ISBN
Exploring our Human Origins (fossil dig)
Nova Curiosity Kit
Artificial Creations (casts to make fossils with)
245 E. Foothill Blvd. Suite 142
Upland, Ca. 91786
Telephone 1 714 949-4215
Kids Discover - Fossil Hunters (see beginning resources)
Skullduggery Inc. (great fossils and kits)
624 South B Street
Tustin, Ca 92780
Nature Science Catalog
Educational Toys Inc.
PO Box 630882
Miami, Florida 33163-0882
Dinosaur set 1 #6113-04 $8.50 (language cards in notes)
Dinosaur set II # 6157-04 $8.05
Dinosaur set III # 6158-04 $8.05
Golden Guide: Fossils
Golden Press ISBN 0-307-24411-3
Fossils Tell of Long Ago ISBN 0-690-04844-0
Dinosaurs are Different ISBN 0-690-04456-9
Dinosaur Bones ISBN 0-690-04549-2
My Visit to the Dinosaurs ISBN 0-690-04422-4
Digging Up Dinosaurs ISBN 0-690-04714-2
Dinosaurs of the Prehistoric Era (good for young people)
Dinosaurs Big and Small
Dinosaurs (easy encyclopedia)
Simon & Shuster Picture Pocket ISBN 0-671-75999-X
The Timeline of Dinosaurs (wonderful!)
Dr. Anglea Milner & Ray Burrows
Galahad Jr. Books ISBN 0-88394-974-1
Dinosaur Dream (fiction)
Aladdin Paperbacks ISBN 0-689-71832-2
Lucille Recht Penner
Random House ISBN 0-679-91207-X
Authur John L'Hommedieu
Child's Play ISBN 0-85953-940-7
Planet Ocean (adult - not for research - good pics of Cambrian animals & continent changes)
Ten Speed Press ISBN 0-89815-778-1
Resources for Vertebrates
Children's Nature Library
Gallery Books ISBN 0-8317-6473-2
Sharks Sharks Sharks
Raintree Steck-Vaughn ISBN 0-8172-3531
Troll Assoc. ISBN 0-8167-2105-X
Guide to Corals & Fishes
Isaz & Jerry Greenberg
Think Like an Eel
Candlewick Press ISBN 1-56402-180-7
Creatures that Glow
Harry N Abrams ISBN 0-8109 4027 - 2
Wings in the Water
Hope Irwin Marison (tape included)
Smithsonian Oceanic Collection: Soundprints ISBN 1-56899-577-6
Harrisii Pub ISBN 0-96992f72-0-7
The World of Frogs
Gareth Stevens Publishing ISBN 1-55532-024-4
Andrienne Soutter Perrot
Brighter Child ISBN 1-56189-178-9
Holiday House ISBN 0-8234-1148-6
Seabirds A New True Book ISBN 0-516-1088-3
Songbirds A New True Book ISBN 0-516-01095-6
Animal World The Penguin
Watermill Press ISBN 0-86592-854-1
National Autobon Society Pocket Guide to N A Birds of Prey
Clay Sutton & Richard Walton
Alfred A. Knoph ISBN 0-679-74923-3
Lyn Littlefield Hoopes
Humane Society of the US ISBN 1-882728-96-3
PO Box 85271 Suite 6
San Diego, Ca 92138
The Hummingbird Book
Donald & Lillian Stokes
Ltiitle, Brown & Company ISBN 0-316-81715-5
Giant Golden Book of Birds (may not be available, but great)
Robert Porter Allen
All About Owls
Scholastic Inc ISBN 0-590-61692-7
First Field Guide (for every vertebrate)
National Audobon Society
Scholastic ISBN 0-590-63982-X
Chameleons are Cool
Scholastic ISBN 0-590-63498-4
Snakes & Lizards (Eye to eye 3-D)
Ladybird Books ISBN 0-7214-5686-3
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I have the students make fossils out of plaster of paris. You can get good kits from several science catalogues. They paint them if they want.
Use a small 3 ounce paper cup. Take several students outside to find a small leaf. Dip the leaf in some oil and place in the bottom of the cup. Pour plaster of paris on top and let dry. Peel the cup away and scratch the leaf off carefully. Voila! A fossil.
Push a shell into a small piece of clay.
Put rocks into
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Ideas for Upper Elementary
All Lower Elementary students should know all the vertebrates and be able to tell the distinguishing features that set them apart. If any cannot then this is their work. I would spend some time on the invertebrates and the other four Kingdoms to be sure everyone understands the whys and wherefore. Then on to Botany. It has been my experience that other than planting and watching things grow, lower elementary students are not that called to Botany. Priscilla Spears (see resources) has updated and revamped the Botany work and this is definitely something that you should look into purchasing.
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Copyright © 2007 Barbara Dubinsky