Free Evolution Unit Study

This is an eleven-week, secular, free evolution unit study perfect for kids in grades 3rd-5th which can be adapted to work for older or younger children. It covers how life evolved from single celled organisms into the current diverse forms of today. The lessons are video documentary intensive but also incorporate a few story books, activities, research opportunities and discussions opportunities for an adult to work on with a child.

Lesson 1: Timeline

Before jumping into a single prehistoric time period or evolutionary event such as the ice age, age of dinosaurs or human evolution it is important to have an overall view of time. To do this create a floor to ceiling timeline beginning with the formation of the Earth and ending with modern day. Draw a line down the paper and divide it into the three Era's of time; Paleozoic, Mesozic and Cenozoic. Leave a small section at the bottom for the pre-Cambrian time period when the Earth was formed and life began. Divide each era further as follows:

 A. 4.5 billion-570 million - Pre-Cambrian

I. 570-245 million - Paleozoic Era

 A. 570-500 million - Cambrian
 B. 500-440 million - Ordovician
 C. 440-410 million - Silurian
 D. 410-360 million - Devonian
 E. 360-290 million - Carboniferous
   i. 360-320 million - Mississippian
   ii. 320-290 million - Pennsylvanian
 F. 290-245 million - Permian

II. 245-65 million - Mesozoic Era (Dinosaurs)

 A. 245-210 million - Triassic Period
 B. 210-140 million - Jurassic Period
 C. 140-65 million - Cretaceous Period

III. 65 million-present - Cenozoic Era

 A. 65-23 million - Paleogene Period
   i. 65-54 million - Paleocene Epoch
   ii. 54-37 million - Eocene Epoch
   iii. 34-23 million - Oligocene Epoch
 B. 23-2.5 million - Neogene Period
   i. 23-5 million - Miocene Epoch
   ii. 5-1.8 million - Pliocene Epoch
 C. 2.5 million-present - Quaternary Period
   i. 2.5 million-11,700 - Pleistocene
   ii. 11,700-present - Holocene

As you journey through evolution, you will be adding images of the creatures that lived during each time period.

Week 2: Mass Extinction Events, Creatures, and Evolutionary Changes 

It is important to have an overall understanding of how life evolved into its current diverse forms before we can truly understand any one part of evolution. Read the book DK Eyewitness Books: Prehistoric Life slowly over a period of several weeks. The book begins with an evolution timeline, followed by a section describing the characteristics of the creatures which were living during each time period.

Add the following mass extinction events and types of creatures to the timeline. Add images of the creatures if you desire.

 A. 4.5 billion-570 million - Pre-Cambrian
    - one celled organisms
     * MASS EXTINCTION EVENT (99% of species died, Earth's surface completely frozen)    

I. 570-245 million - Paleozoic Era

 A. 570-500 million - Cambrian
    - shells evolved
    - shallow seas
    - molluscs, sponges, trilobites
    - all animals were aquatic
 B. 500-440 million - Ordovician
    - jawless fish
    - early land based plants
    - 1st vertebrates
     * MASS EXTINCTION EVENT (60% of marine species died, Earth cooled)
 C. 440-410 million - Silurian
    - jaws evolved
    - spore based plants
 D. 410-360 million - Devonian
    - lots of oxygen
    - limbs evolved (1st tetrapods)
    - 1st land animals (amphibians)
    - wingless insects and spiders
 E. 360-290 million - Carboniferous
    - plants evolved
    - mostly spore based plants
    - amniotic eggs evolved
    - 80% Oxygen
    - lots of giant insects
   i. 360-320 million - Mississippian
   ii. 320-290 million - Pennsylvanian
 F. 290-245 million - Permian
    - primitive reptiles
     * MASS EXTINCTION EVENT (95% of species died, Severe volcanic eruptions)    

II. 245-65 million - Mesozic Era (Dinosaurs)

 A. 245-210 million - Triassic Period
    - ferns in south, conifers in north
    - hot and humid
   - 1st flowering plants
    - marine reptiles (plesiosaurs, ichthyosaurs)
    - flying dinosaurs (pterosaurs)
    - 1st dinosaurs (size of small turkeys)
    - primitive mammals
 B. 210-140 million - Jurassic Period
    - plant and meat eating dinosaurs
    - pterosaurs were abundant
    - marine animals (ichthyosaurs, plesiosaurs, crocodiles, bivalves)
    - brachiopods, allosaurs

 C. 140-65 million - Cretaceous Period
    - ray fish widespread
    - 1st sharks
    - 1st flowers and grasses
    - dinosaurs (T-Rex, triceratops, velociraptor, spinosaurs)
    - birds evolved
    - 1st ants, butterflies, grasshoppers
    * MASS EXTINCTION EVENT (Asteroid Impact)

III. 65 million-present - Cenozoic Era

 A. 65-23 million - Paleogene Period
   i. 65-54 million - Paleocene Epoch
    - turtles, crocodiles, lizards, fish
    - nocturnal mammals
   ii. 54-37 million - Eocene Epoch
    - running animals (horse)
    - grasses evolved and prairies formed
    - beech elm, chestnut, magnolia, redwood, larch, cedar trees
    - small mammals
   iii. 34-23 million - Oligocene Epoch
    - elephants and rhinos
    - cooler climate (woodlands)
    - 1st apes
 B. 23-2.5 million - Neogene Period
   i. 23-5 million - Miocene Epoch
    - increased grasslands
    - cooler, dryer climate
    - cattle and deer evolved
    - wolves, horse, deer, birds - similar to today
   ii. 5-1.8 million - Pliocene Epoch
    - modern climate - deciduous and coniferous forests, tundra, grasslands and deserts
    - 1st humans
    - seals and sea lions thrived (mammals)
    - Mediterranean Sea formed
 C. 2.5 million-present - Quaternary Period
   i. 2.5 million-11,700 - Pleistocene
    - Great Lakes formed
    - glaciers formed and retreated 
    - some mammals became extinct (mastodons, saber-toothed cats, grounds sloths, cave bears)
    - Neanderthals became extinct
    - migratory birds evolved
    - smaller, swifter mammals developed
   ii. 11,700-present - Holocene

Week 3: Pre-Cambrian

Surprisingly, it was a mass extinction event which gave rise to life on the planet during the Cambrian period of history. Before the Cambrian the only known life was single celled organisms. The seas were filled with a type of blue-green algae known as scieno-bacteria. Then a series of events took place which caused the Earth to freeze. It was the devastating ice age which caused the bacteria to evolve by surviving the harsh conditions.

Watch the series of videos, Catastrophe: Miracle Planet, which focuses on mass extinction events throughout the history of our planet. The first two episodes detail the ice age which took place between the pre-Cambrian and Cambrian periods of evolution.

Scientists believe the Earth was completely covered with ice at least two times since it was formed, hence the title of the video "Snowball Earth". At one time the air was filled with methane gas giving the atmosphere a reddish hue. Then one celled organisms which produced oxygen began to thrive changing the red to blue. The abundance of oxygen then caused the planet to freeze. Although the surface was frozen, forces beneath were still very active. Plates continued to move and volcanoes continued to erupt. Volcanoes erupting on the surface spilled carbon dioxide into the atmosphere. After years of eruptions, the carbon dioxide built up and rewarmed the planet. The increased temperature caused the ice to melt and life to once again thrive.

Episode 2 of Miracle Planet, Snowball Earth continues discussions of how the Earth was once completely covered by ice. 650 million years ago, there were no plants and animals to balance the carbon dioxide, oxygen and other gases within the atmosphere. Scieno-bacteria, one of the only living creatures, absorbed carbon dioxide. After years of carbon dioxide use, the gas became depleted in the atmosphere. Since carbon dioxide keeps the Earth warm, the lack of carbon dioxide allowed the planet to freeze. In addition to exploring how the Earth froze and later thawed, scientists explore winter caves to see how single celled organisms may have survived when the Earth was frozen. They also explain how they had altered DNA which enabled them to survive. It was this mass extinction event between the Pre-Cambrian and Cambrian period that was the turning point for life to thrive.

Week 4: Paleozoic Era


The Cambrian Period was the first time of widespread life on Earth. While the land was barren, the seas saw an explosion of life. The single celled organisms of the Precambrian developed into multi celled creatures. At first creatures had soft bodies, but during the Cambrian Period, the first shells were developed. Watch this video on the Cambrian Explosion of life.


During the Ordovician Period the warm shallow seas were filled with trilobites, sea scorpions and coral. Nautiloids evolved and after 25 million years of volcanic eruptions, the atmosphere was filled with carbon dioxide. The major evolutionary advancement of the backbone led to the evolution of the first fish.

Watch this video which features Nigel, who travels back in time to venture into the ancient seas. In addition to featuring the Ordovician Seas, Nigel explores other prehistoric environments. 


The Silurian Period gave rise to the first land based plants. The evolution of jaws was a major event as predators became much more dangerous. Watch this video on the evolution of jaws.


During the Devonian Period large armored fish ruled the seas and the first sharks evolved. The air was rich with oxygen, and the first creatures developed the capabilities of breathing air and walking on land. Plants which had evolved during earlier periods became numerous upon the land. Forests began to grow and the shade proved by the trees provided shelter for land animals. Watch this video which explores the links between prehistoric creatures and the first tetrapods.


This was the age of giant insects as 80% of the atmosphere was filled with oxygen. The mass of trees led to the first dirt. Creatures developed the capability to produce hard shelled and amniotic eggs which led to the evolution of mammals and reptiles. Hearing developed and the relationship between carnivores and herbivores was established.


During the Permian Period mammals and reptiles continued to evolve on land.

Paleozoic Era

Overall the Paleozoic Era saw major changes in life on Earth. From single celled organisms to shells, backbones, jaws, limbs, lungs and eggs - specialization was beginning to take place. The video linked below covers the entire era.

To remember the major events of the Paleozoic Era, memorize this song to the tune of Little Bunny Fu-Fu.

5-4-3-2-1 Boom
4.5 billion years ago the Earth was formed
Single celled bacteria lived in blue-green water

5-4-3-2-1 Frozen
Carbon dioxide levels fell and Earth became a snowball
Volcanoes warmed the Earth after 25 million years

C-O-S-D-C-P Cambrian
Multi-celled creatures evolved in the seas
First they had soft bodies, then some developed shells

C-O-S-D-C-P Ordovician
Shallow seas, warm water, lots of carbon dioxide
The first fish developed without any jaws

C-O-S-D-C-P  Silurian
Creatures developed backbones and fish got jaws
Plants began to grow upon the land

C-O-S-D-C-P Devonian
The air was full of oxygen and forest began to grow
Tetrapods with four limbs walked upon the land

C-O-S-D-C-P Carboniferous
Giant insects flew about in oxygen rich air
Reptiles evolved with shelled eggs and hard scales

C-O-S-D-C-P Permian
The first mammals evolved and they could hear
Reptiles ruled the land until..............

5-4-3-2-1 Boom
Volcanoes erupted for hundreds of thousands of years
Acid rain, volcanic winters, the food chain collapsed

Carbon dioxide in the air warmed the Earth and sea
95% of species died but some survived


Add creatures which lived during the Paleozoic Era to your timeline.

Lesson 5: End of the Paleozoic Era

What brought the Paleozoic Era to its end?

The Paleozoic period of evolution was brought to a close with a mass extinction event which lasted over 100,000 years. Massive volcanic eruptions, known as flood basalt eruptions, took place in Siberia. The eruptions released sulfur dioxide gas into the atmosphere which mixed with water causing acid rain. The acid rain lead to a series of volcanic winters which caused the food system to collapse. As if that wasn't bad enough, the carbon dioxide released by the volcanoes then caused the Earth to warm. The warming resulted in altered global weather patterns. In addition, the warm air caused the ocean temperatures to rise eventually causing them to stop circulating. This created a lack of oxygen in the seas which in turn resulted in numerous creatures becoming extinct. Watch the video Catastrophe - Episode 3: Planet of Fire which is part of series which focuses on mass extinction events. Episode 3 focuses on the extinction which occurred at the end of the Paleozoic Era.

Lesson 6: Mesozoic Era

The Mesozoic Era was the time of the dinosaurs. It can be broken into three time periods; Triassic, Jurassic and Cretaceous. The first flowering plants, marine reptiles, flying dinosaurs and first small dinosaurs evolved during the Triassic. During the Jurassic Pterosaurs were abundant. The Cretaceous gave rise to the first sharks, birds and dinosaurs. Triceratops, and t-rex roamed the land. Mammals made their first appearance during the Mesozoic.

Watch these videos about Mesozoic Era sea creatures of the Triassic, Jurassic and Cretaceous periods.

Miracle Planet Part 4, Extinction and Rebirth describes how volcanic eruptions lead to a change in composition of the Earth's atmosphere. Among other elements, oxygen levels first rose and then fell dramatically to around 10%. The video explains how one change led to another such as the unique formation of mammal rib cages. In early species the rib cage completely surrounded the chest, but in later species, the ribs only surrounded the upper chest much like our ribs do today.

Pterosaurs evolved during the Mesozoic Era with wings, huge breast bones and unique landing tactics. Watch the National Geographic video Largest flying Creature Ever - Pterosaurs which features scientists who try to replicate pterosaur flight.

Sauroposeidon were a species of long necked dinosaur which laid numerous small eggs. It's believed that the parents abandoned their babies (500 per season) and let them fend for themselves. T-Rex dinosaurs, on the other hand, are believed to have been devoted parents. Watch Dinosaurs Part 1 Extreme Survivors which explores different species of dinosaurs and their behavior characteristics.

Long neck dinosaurs, abounded during the Jurassic. During the Cretaceous the t-rex preyed upon creatures. It is believed that these two species didn't live at the same time and that there may have been even larger dinosaurs. Watch Extreme Dinosaurs which explores the possibility of a dinosaur even bigger than t-rex discovered in South America - giganatosaurus, living at the same time as the giant Argentinosaurus, the largest plant eater. While exploring the theory, scientists examine evidence that suggests these species of large dinosaurs may have lived in family groups.

While dinosaurs roamed the land, the seas teamed with life. Watch the National Geographic video Sea Monsters - A Prehistoric Adventure which gives a historical fiction account of a dolichorhynchops (a pre-historic dolfin which lived during the late Cretaceous.) Follow the dolichorhynchops and her brother as they journey through life. The video introduces several other sea creatures of the late Cretaceous.

Add Figures to Your Timeline

After learning about different Mesozic Era creatures add images to the timeline.

 Search through books to locate creatures and sketch them for the timeline.

 Photocopy creatures pictured in books and cut them out for the timeline or print images from the internet for your timeline.


Lesson 7: End of the Cenozoic Era

Scientists divide time into three eras; Paleozoic, Mesozoic and Cenozoic. Each era is further divided into periods. At the end of each era and period extinction events wiped out life. The extinction events which occurred at the end of each era were much more devastating than the extinction events which happened during the eras. Both caused large numbers of creatures to become extinct. After each extinction event new and different life forms were allowed flourish.

The first major extinction event began with a complete freeze of the Earth and happened at the beginning of the Paleozoic Era. The second mass extinction event occurred between the Paleozoic and Mesozoic Eras and was brought on by a massive volcanic eruption in Siberia. The final mass extinction event was caused by an asteroid impact at the end of the Mesozoic Era. 

Today it is widely accepted that 65 million years ago an asteroid struck our planet and wiped out  most life on Earth including the dinosaurs. The video below tells the story.

Lesson 8: Cenozoic Era Creatures

The first mammals evolved during the Mesozoic Era, but after the mass extinction event which wiped out the dinosaurs, those mammals began to develop individual features. Horses, elephants, and hundreds of other mammals developed unique characteristics which enabled them to thrive. As the mammals continued to evolve, so did the reptiles and fish. Unique creatures such as turtles, lizards, and crocodiles became abundant. Grasslands spread across the land and with them mammals such as cattle and deer became equipped to survive in their new environment.

The Cenozoic Era also gave rise to human evolution which will be the subject of the next lesson. The last great ice age when the woolly mammoths and saber toothed cats ran wild was part of the Cenozoic Era as well as modern humans living today. This video gives an overview of the time period.

 From the Fall of Dinosaurs to the Rise of Humans

For much of history the continent of Australia was separated from the rest of the Earth's land mass. Therefore, the creatures which evolved in Australia are the most unique on the planet. Poison, pouches and combinations of features found nowhere else are found in unique creatures that live in Australia. The platypus is perhaps the oddest of them all. Watch And the Mammals Laid Eggs which describes several Australian animals and their history of evolution.


Search the internet for images of creatures to place onto your timeline.

Lesson 9: Human Evolution

Six million years ago chimps and humans shared a common ancestor. In the years in between  numerous human-like creatures lived on the planet. "Lucy," the name given to a 3.2 million year old fossil found in Africa was the species Austrolopitheaus Afarensis. From the waist down she was like a human, but from the waist up, her features were more ape-like. Living in a tropical rain forest, it is believed that some ape like creatures developed legs that enabled walking thus giving them an advantage over certain other apes.

Watch the video Becoming Human from which describes several species of early humans that evolved from Austrolopitheaus Afarensis. Some lived only to evolve into other species and die out. The traits common and unique between species closely related are explained in detail.

Becoming Human

Neanderthal were a species of early human which lived at the same time as Homo Sapiens, 35,000 years ago. They lived primarily in Europe and western Asia and were well adapted to survive in the cold climate of the period. 

Neanderthal: Episode 1 - Evolution History Documentary shows the species living their lives. Separated into small family groups of 7-20 people, they lived in caves and ate mostly meat. They were great hunters, cared about members of their clan and rarely lived to the age of 40. 

Neanderthal: Episode 1 - Evolution History Documentary

The History Channel video From Ape to Man follows the discoveries of different human like species during the 1800s and 1900s. If you can't find the video on youtube, try the History Vault, a low cost streaming service from the History Channel. When Charles Darwin wrote about his evolution theory, the scientific world didn't pay much attention. Several years later his ideas gained popularity and anthropologists began searching for "the missing link." At first scientists believed they would discover one species which would be a transition between humans and apes, but after several different discoveries, their ideas changed. Many human-like species have been discovered. Some are direct ancestors of humans, and others are more like cousins that became extinct.

Birth of Civilization is a video which serves as a good transition between the human portion of evolution study and ancient history studies as it explaines how people began living together in groups.
Birth of Civilization 


After learning about how humans evolved, add pictures of pre-historic species of human-like creatures to your timeline.

Notice how close to the top of the timeline the human-like creatures lived.

Also note that humans did not live at the same time as the dinosaurs, but did live at the same time as early three-toed horses, woolly mammoths and other early mammals.

Lesson 10: The Last Great Ice Age

At the end of the last great ice age humans made an extraordinary journey which brought them to a new continent. Several theories explain how humans could have come to live in the Americas, but scientists and historians currently lack the evidence to know with certainty. Rather than explain how humans evolved, the video linked below describes how early humans lived. During the time when woolly mammoths roamed the planet, these early humans would have likely been the prey of saber toothed cats. 

Around the end of the last ice age an extinction event occurred which wiped out the mammoths, saber toothed cats and other ice age creatures. It devastated human populations, but didn't destroy human life. Many scientists believe an asteroid hit the United States in the area of Ohio, but since impact was atop of a glacier, there is no crater evidence.

Lesson 11: Wolves in Yellowstone

Mankind didn't understand the process of evolution until Charles Darwin introduced his theory. Scientists have greatly expanded on his foundational ideas and have an even better understanding of evolution today. Read the book One Beetle Too Many to understand how Charles Darwin was transformed from a bug collector into a revolutionary thinker. Evolution is an ongoing process that is still happening today.

The children's book Once A Wolf: How Wildlife Biologists Fought to Bring Back the Gray Wolf tells the story about how wolves became extinct in the American West and were later reintroduced. Shockingly it was laws which commonly encouraged practices that led to extinction. In 1995 scientists and biologists decided to reintroduce the wolves to Yellowstone. The population has since boomed and led to numerous ecological changes as discussed in the short video below.

Creatures don't have much control over mass extinction events such as ice ages, meteors and volcanic eruptions. They do have some control when it comes to the extinction of individual species in the short-term of time. After studying wolves in Yellowstone, discuss when humans have and do not have control when it comes to evolution.

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