Evidence for Evolution

Evidence for Evolution

Click through to gather evidence, read the slides, and answer questions to solve the ultimate question!

feature that a species inhereted from a common ancestor that is not necessary currently

Multiple species derive from a single ancestral population

The total sum of what we know about fossils

The study of how various embryos develop similarly

EmbryonicDevelopment

Fossil Record

Common Ancestors

Vestigial Structures

WHAT IS A THEORY?

theory – (as used within science)

• A likely explanation for something we can observe in the natural world.
• It has significant evidence to support it, so it is generally accepted to be true, but it’s not “proven” in the same way as a scientific law. Ex. Einstein’s Theory of Relativity

Survival of the fittest

Natural Selection

START HERE

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

WRONG

back

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

Natural Selection

Evidence for Evolution

What do scientists today use as evidence for the theory of evolution?

Survival of the fittest

feature that a species inhereted from a common ancestor that is not necessary currently

Multiple species derive from a single ancestral population

The total sum of what we know about fossils

The study of how various embryos develop similarly

EmbryonicDevelopment

Fossil Record

Common Ancestors

Vestigial Structures

WHAT IS A THEORY?

theory – (as used within science)

• A likely explanation for something we can observe in the natural world.
• It has significant evidence to support it, so it is generally accepted to be true, but it’s not “proven” in the same way as a scientific law. Ex. Einstein’s Theory of Relativity

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!

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.

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Natural Selection

Evidence for Evolution

What do scientists today use as evidence for the theory of evolution?

Survival of the fittest

feature that a species inhereted from a common ancestor that is not necessary currently

Multiple species derive from a single ancestral population

The study of how various embryos develop similarly

EmbryonicDevelopment

Common Ancestors

Vestigial Structures

WHAT IS A THEORY?

theory – (as used within science)

• A likely explanation for something we can observe in the natural world.
• It has significant evidence to support it, so it is generally accepted to be true, but it’s not “proven” in the same way as a scientific law. Ex. Einstein’s Theory of Relativity

Fossil Record

The total sum of what we know about fossils

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!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.

Natural Selection

Evidence for Evolution

What do scientists today use as evidence for the theory of evolution?

Survival of the fittest

feature that a species inhereted from a common ancestor that is not necessary currently

Multiple species derive from a single ancestral population

The total sum of what we know about fossils

The study of how various embryos develop similarly

EmbryonicDevelopment

Fossil Record

Vestigial Structures

WHAT IS A THEORY?

theory – (as used within science)

• A likely explanation for something we can observe in the natural world.
• It has significant evidence to support it, so it is generally accepted to be true, but it’s not “proven” in the same way as a scientific law. Ex. Einstein’s Theory of Relativity

Common Ancestors

Common Ancestry

A common ancestor is an ancient organism that shares traits with those alive today. There is a lot of evidence to support the idea of common ancestry. Two main sources for studying ancestry include studying fossils andcomparing characteristics.

A group of animals known as marsupials all have a pouch for carrying their young. This characteristic suggests that these different species share a common ancestor.

A quokka also displays the characteristic marsupial pouch.

A kangaroo displays the characteristic marsupial pouch.

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Common Ancestry

An ancestor is a species from which a modern species evolved. 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?

Common Ancestry

WHOOPS! read the info hereand click "try again"

A group of animals known as marsupials all have a pouch for carrying their young. This characteristic suggests that these different species share a common ancestor.

A quokka also displays the characteristic marsupial pouch.

A kangaroo displays the characteristic marsupial pouch.

Try again

Common Ancestry

Correct!Scientists use the idea of common ancestry to explain how all living things on Earth are related. Common ancestry means that all living things in the present share a single ancestor deep in the past.

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Natural Selection

Evidence for Evolution

What do scientists today use as evidence for the theory of evolution?

Survival of the fittest

feature that a species inhereted from a common ancestor that is not necessary currently

Multiple species derive from a single ancestral population

The total sum of what we know about fossils

The study of how various embryos develop similarly

EmbryonicDevelopment

Fossil Record

Common Ancestors

Vestigial Structures

WHAT IS A THEORY?

theory – (as used within science)

• A likely explanation for something we can observe in the natural world.
• It has significant evidence to support it, so it is generally accepted to be true, but it’s not “proven” in the same way as a scientific law. Ex. Einstein’s Theory of Relativity

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!

Goosebumps

There are other vestigial structures in humans and animals. Click to learn about our appendix!

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.

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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!

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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

NOPE! Read this and try again!

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!

Try again

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.

Congrats, you finished!Click here to continue

Vestigial Structures

Natural Selection

Survival of the fittest

feature that a species inhereted from a common ancestor that is not necessary currently

Click Here When Done!

Multiple species derive from a single ancestral population

The total sum of what we know about fossils

The study of how various embryos develop similarly

EmbryonicDevelopment

Fossil Record

Common Ancestors

WHAT IS A THEORY?

theory – (as used within science)

• A likely explanation for something we can observe in the natural world.
• It has significant evidence to support it, so it is generally accepted to be true, but it’s not “proven” in the same way as a scientific law. Ex. Einstein’s Theory of Relativity

Evidence for Evolution

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