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Evidence for EvolutionStations

Directions:On the next page, you will see multiple "stations" to complete. Please start with Evolution Station One, but from there you can go in any order!Watch all videos, read all articles, and complete all activities!

You can work in a breakout room with group members or individually in an independent breakout room.At the end of each station, you will see a key word.The key word will be used to start the next station.

Don't forget your key words!

Evidence For Evolution Stations

Evolution Station one

START HERE!

Common Ancestry

Fossil Records

homologous & analogous structures

Vestigial Structures

Embryological Evidence

Changes IN Hominids

Bonus: Coevolution

Bonus: blooket

Click the eye to return to the directions

Evolution station one

The theory of evolution is one of the most important concepts in biology.Click the naturalist below who first described evolution by natural selection.

Albert Einstein

Isaac Newton

Charles Darwin

Right! Charles Darwin first described evolution! He noticed that populations of organisms change over time and become better suited to survive and reproduce in their specific environments.

Click on the animal on this slide with the best traits for this environment

The grasshopper has the best traits because of its camouflage! Evolution is sometimes summarized with the phrase "survival of the fittest." Living things compete for resources. Those organisms that are more fit to do this will survive and reproduce better than others. These organisms will become more numerous.

In this environment, which organism is "fittest"?

Which of the following organisms has a body structure most similar to a lion?

Not many people would suggest a shark is "fitter" than the Hulk, but in this case it definitely is! So how does evolution happen? Speciation is the process of one species branching into two. In some cases, differences in ability to get food or to escape from predators can lead to speciation. ​These species usually have similar traits, but can no longer breed.

Right! Lions and tigers have similar body structures and traits. This leads scientists to consider that they may have a common ancestor. Continue through the stations to learn more!

Key Word:Tiger

Common Ancestry

An ancestor is a species from which a modern species evolved. In some ways, this is a probability problem.For example, all mammals have fur and birds always have wings.

Is it more likely that thousands of mammal species evolved furry coats at different times?

Or is it more likely that they all evolved from the same species?

Correct! This species would be a common ancestor of all living mammals with fur. One way to informally organize common ancestors is to use a cladogram.

A cladogram branches off as a species develops new traits.Click on the organism closest related to the fish.

The salamander is the closest related organism! However, one difference is that the salamander has lungs!

Drag and drop the organisms into their placement on the following Cladogram! When you're done, click the arrow to check your answers

Check Your Answers!

Your cladogram on the last page should look like this!Great job on this station! The other stations will describe the types of evidence we have for common ancestors.Go back to the main zoom room and tell your science teacher the key word. Then continue onto your next station using the home button in the bottom left corner!

Key Word:Fish

Fossil Records

We now know that many species adapt from common ancestors.But how do we know what those ancestors looked like?Click on the diagram of the fossil record to continue.

the Fossil record analyzes, dates, and organizes fossils.The fossil record helps paleontologists, archaeologists, and geologists place important events and species in the appropriate geologic era.We can learn about the changes in species over time by analyzing the fossil remains.

below is a link to a gallery of fossil horses. Take a few minutes to check out the differences!when you're ready, click the arrow to move to the next page.

Notice the differences between the species of horses over time!take a look at it's feet- notice it had toes 50 million years ago, and now they have hooves!did you notice the difference in size?click on the modern day horse to move on.

Transitional species are species that are intermediate (a mix) between two different species.

for example, as amphibians evolved from fish, we should see evidence of a transitional species, having traits of both fish and amphibians.

Click on the transitional species in the diagram

Right! That is a tiktaalik!The tiktaalik lived about 375 million years ago. It had fins, scales, and gills- all signs that it was a fish.

However, it also had a flattened body and head- which fish do not have!

Click on its flattened head to learn more!

The tiktaalik also had a neck that seperated its head from its body, digits on its forelimbs, and eyes on the top of its head. It was clear it had features of a land animal.

Using fossil records is just one type of evidence we have of common ancestors. check out the other stations for more types!

key word:record

homologous and anaologous structures

Homologous Structures and Analogous Structures provide evidence for common ancestors. Watch the video below for an introduction about these structures. When you're done, click on the HOMOLOGOUS Structures to the right.

Yes, the forelimbs of various animals in the picture is an example of Homologous Structures!Let's take a more detailed look!

Homologous Structures are organs, limbs, and other structures that look similar in structure, but may have different functions.If you look closely at the picture of the limbs on these animals, you will see some have a completely different function, but have all evolved from a common ancestor.They all have a humerus that leads to a radius and ulna, which leads to the carpals and metacarpals and finally phalanges.Click on the Whale's phalanges (fingers) to move to the next page.

Analogous structures are the opposite. They have different structures, but serve the same function. Take a look at the examples to the right.These do not provide evidence because the structures formed independently to serve the same purpose without a common ancestor.

Click on one of the analogous structures that help an organism fly to practice analyzing these structures!

HOMOLOGOUS STRUCTURES

ANALOGOUS STRUCTURES

Drag the following pictures to the correct type of structure.Click the arrow to move on when you're done!

Human and turtle heart

A platypus and duck both lay eggs

Ankle bone of a pig and deer

Dorsal fin of a dolphin and shark

Giraffes and humans both have 7 vertebrae in our necks!Which type of structures does this give evidence for?

HOMOLOGOUS STRUCTURES

ANALOGOUS STRUCTURES

That's right! Giraffes and humans have similar structure of vertebrae provides evidence for homologous structures. This suggests we have a common ancestor!

Key Word:Giraffe

Vestigial Structures

As organisms evolve, there are often remaining structures that haven't fully disappeared.But they have lost most or all of their original purpose.

Do you have one?!Try it out!Put your pinky and thumb together as shown.Does your tendon stick out?

YES

NO

About 10-15% of people don't have this tendon!This tendon has no effect on grip strength or really anything else.It is completely useless!

80-85% of people do have this tendon, though, because if a structure isn't negatively affecting the organism, it most likely won't disappear entirely!

It does, however, provide evidence that they may share common ancestry with other organisms that do use that body part, organ, or structure!

Appendix

Dog's Dew Claw

Click the buttons on the rainbow to check out multiple vestigial structures.When you're done, click the arrow below!

Goosebumps

Wisdom Teeth

Ear Rotation Muscles

Dog's Dewclaw

The dewclaw is present on many animals.It's something that has evolved into a thumb in others.Ancient ancestors to the dog once used this structure to climb trees, but as dogs evolved to run on the ground and stand more on their digits than their whole foot, their dewclaw became mostly useless.

Goosebumps

What's the point of these?Most animals that have fur can lift these muscles up to stand up their fur.This allows more air to be trapped in their fur for insulation and keeping warm.Goosebumps also happen when an animal gets scared or feels threatened to make its hair stand up.

How about for people though?Useless!We have so many little hair on our bodies that goosebumps do nothing to keep us warm.

Appendix

Humans have an appendix which many believe serves as a housing for good bacteria in our intestines, so it may actually serve a purpose for us- but it is believed that the original pupose of the appendix may have changed. The appendix helps many other animals in digesting cullulose-rich diets, such as grass.

Wisdom Teeth

Some humans have wisdom teeth. They hardly fit into most of our skulls nowadays, which is why some people have to have them removed!Human skulls have changed over milions of years. They used to be longer, allowing more room for teeth in the jaw.Once humans could cut foods, cook foods softer, and use agriculture, our need for stronger jaws decreased.

Now one in four people are missing at least one wisdom tooth.It wouldn't be surprising if no one had any wisdom teeth another million years from now!

Ear Rotation Muscles

Can you move your ears? If so, probably just slightly.We still have ear rotation muscles, but they are have lost their original function.

Some animals have the ability to rotate their ear 90 degrees or more to help them locate the direction of sounds and hear better.Studies show that our brains subconsciously tell our ears to turn towards sounds, too, even though they no longer rotate!

Vestigial Structures

Now that you've learned about a few examples, answer the following question!Which of the circles describes a vestigial structure?

A whale's leg bones

A cat's tail

Human's fingers

A bird's beak

Great job! A whale's leg bones are vestigial structures that suggest that they have a common ancestor that once lived on land. The species adapted and gradually lost their legs, but retained the vestigial bones.

Key Word:Whale

Embryological Evidence

Embryology is the study of the development of embryos (an organism before it's born or hatched) across different species.Scientists have found that organisms with a common ancestor have similar traits during early embryological development.

Click the embryos above to see more examples

How similar are they?Try to pin each organism's name under its early embryo

Rabbit

Human

Calf

Hog

Tortoise

Salamander

Fish

Chick

Click Here When You're Done!

How about now?Try to pin each organism's name under its late stage embryo

Rabbit

Human

Calf

Hog

Tortoise

Salamander

Fish

Chick

Click Here When You're Done!

Click on the embryos that were HARDER to label!

However, as they continue to grow, they change drastically due to their adaptations that help them survive in their environment. Click the early human embryo to move on

Yes! It was very difficult to tell the early embryos apart!That's because of how similar the traits are in all of these organisms!All vertebrate embryos essentially have the same parts to start.

All vertebrate embryos also have what looks like "gill slits," but are not actually gills. These structures in embryos are called pharyngeal arches. These are exposed (visible outside) early in embryo development but eventually they close in many species.​

Click the arrow to find out what the pharyngeal arches become.

Only in fish and in larval amphibians do pharyngeal arches develop into gills.​ In mammals, the tissue within the first two gill slits forms part of the lower jaw and the bones of the inner ear.

Key Word:Baby

Changes in Hominids

Hominids are a family of primates that walk upright on two legs, including today's humans and our extinct ancestors!Hominids first evolved about 6 millions years ago. Humans are the only hominids alive today!Like most organisms, we are a part of a large and diverse family tree that has many branches, with many changes along the way.

Watch the video in the link below and take note of the characteristics that were more advantageous in some species and how humans' ancestors became more advanced as time passed.When you're done, click the arrow to learn more!

The earliest hominid skeletal fossil dates back 6 million years to Ardipithecus ramidusThese early ancestors could walk upright, but had huge big toes, which allowed it to mostly live in trees

Scientists have measured the heights of fossil skeletons and the patterns of their fossil footprintsOver time, ancestors got taller and their feet changed as they got better adapted to walking on the ground

Click on the Australopithecus aferensis skeleton "Lucy" to learn more!

Fossils of Skulls

Over time, hominid skulls have changed in the following ways...-Jaws and teeth have decreased in size because straw jaws were no longer needed as we began cooking softer foods-Brain size has TRIPLED to develop the precise motor skills needed to make and use tools, to track and predict movements of the animals they hunted, and to develop spoken language

Click the skull of the earliest hominid fossil.

Increased height and weight

Working cooperatively with each other

Wider pelvic bones

Yes! Did you notice how the skulls have changed?Here are some other changes that hominids have gone through over time!

Using tools

How cool is it that hominids have changed so much?Well, that's it for this station!

Go back to the main zoom room and tell your science teacher the key word. Then continue onto your next station using the home button in the bottom left corner!Before you go, check out the chart below!

Key Word:Sapiens

Bonus: coevolution

If we find two species that can NOT survive without their dependence on each other, this is considered evidence of Coevolution.These two species changed and evolved together over time.Click on the bees and flower above to learn more!

If you are on this page, this means that you have completed EVERY OTHER STATION already!If that is the case, let's learn about coevolution!

Bees and flowers are popular examples of coevolution.

Think About It:-Pollination by animals is critical to the reproduction of most plants-Bees are the most familiar pollinatorsThis coevolution created a mutually beneficial relationship:Bees were safe from predatorsBees got foodFlowers were able to produce more seedsClick on the bee for another example.

Here's another example!

Other examples are common among predator-prety and host-parasite pairs.

Click the Mimic Butterfly to test your knowledge!

Click the circle below that shows an example of coevolution.

Whales and penguins have fins/flippers for moving in water.

Ostriches and giraffes are both native to the savannahs and have a very long neck.

Bees see yellow and blue well. Bee-pollinated flowers are usually yellow and blue with a narrow tube.

Great job finding the example of coevolution!

You've made it to the end of this station!Go back to the main zoom room and tell your science teacher the key word. Then continue onto the very last station using the home button in the bottom right corner!

Key Word:Bee

Bonus: Blooket

If you are on this page, this means that you have completed EVERY OTHER STATION already!If that is the case, feel free to practice our topic using the Blooket link in the icon below!