6. Review and Embryology

IMPORTANT!!!

There is an activity that goes with
these slides. Do NOT start it until

you get to slide 78.

Evolution

Essential Question:

Do organisms Evolve?
(Do organisms change

over time?)

There are three main pieces of evidence
that scientists use to prove evolution.

● Fossil evidence
● Comparative anatomy
● Embryology

Paleontology--The Study of Past Life

Paleontologists look
for fossils, or the
remains of ancient
organisms.

(they study fossils of
old dead things)

Fossils are formed when a plant or animal dies in a watery
environment and is buried in mud and silt quickly.

Fossil
formed
No
Fossil
formed

Fossils are rare

It is estimated that 1 in 80
million T-Rex became
fossilized. That is why
intact fossils are so
expensive.
($31.8 million)

Most of the
evidence for
Evolution of
organisms
comes from
fossils

Which organism lived the longest?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Multiple Choice

Which organism lived the longest?

• A

• B

• C

• D

Which organism lived the longest?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Which organism lived the longest?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Which organism lived the shortest amount
of time?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Multiple Choice

Which organism lived the shortest amount of time?

• A

• B

• C

• D

Which organism lived the shortest amount
of time?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Which organism went extinct?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Multiple Choice

Which organism went extinct?

• A

• B

• C

• D

Which organism went extinct?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Which organism is widely distributed?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Widely Distributed

Multiple Choice

Which organism is widely distributed?

• A

• B

• C

• D

Which organism is widely distributed?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Widely Distributed

Index fossils are:

Fossils of widely
distributed
organisms that lived
during only one
short time period.

An Index Fossil is widely distributed and short lived.

Widely Distributed

Short
Lived

Which organism would make the best index
Fossil?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Multiple Choice

Which organism would make the best index Fossil?

• A

• B

• C

• D

Which organism would make the best index
Fossil?

Fossil
Layer 5

Fossil
Layer 4

Fossil
Layer 3

Fossil
Layer 2

Fossil
Layer 1

A

B

C

D

Index Fossils
help tell how old
the rock around
it is

Through carbon
dating this index
fossil dates at
about 245 to 65
million years old.

Which suggest the rocks
around it are also 245 to
65 million years old.

So any other
fossils around
it would have
to be that old
also.

You don’t
find modern
day elephant
fossils when
you dig down
deep in the
ground.

You find fossils
that are
similar but not
exactly the
same.

Which gives
more
evidence to
the fact that
organisms
have changed
over time.

The study of comparative anatomy compares
similar structures (arm to arm, leg to leg for
example) of different organisms.

Comparing anatomy provides evidence organisms

changed over time

The limbs are built the same way

The limbs are structured in the same order

Comparative anatomy provides evidence for

evolution of organisms.

Comparative anatomy provides evidence for

evolution of organisms.

Although different species(types of animals) these limbs

all have the same parts in the same place.

So basically it’s like this.

Evidence of skeletal structures suggests that all organisms

evolved from similar organisms because they have the same parts.

Remember us

Evolution of Whales

The left over hip bone in whales suggest that whales once

walked on land. So they have changed over time.

There are three main pieces of evidence
that scientists use to prove evolution.

● Fossil evidence
● Comparative anatomy
● Embryology

They are both birds

Pigeon

Duck

But they are different species

They are similar.

Two wings, two feet, two eyes etc…..

But they are not the same.

Pigeon

Duck

It makes sense that at one time they had a common
ancestor and evolved (changed over time) in different ways

Pigeon Duck

Common
Ancestor

agree or disagree

Both of these are dogs?

They are similar.

Four legs, fur, two eyes etc…..

But they are not the same.

Real dog

Large rat :)

Sorry I apologize

It makes sense that at one time they had a common
ancestor and evolved(changed over time) in different

ways.

Common
Ancestor

Common Ancestor

Common Ancestor

Common Ancestor

Common Ancestor

Common Ancestor

Cladogram
Activity

Multiple Choice

Which organisms are most closely related?

• 5 & 6

• 6 & 7

1. Which
organisms are
most closely
related?

a. 5 & 6

b. 6 & 7

1. Which
organisms are
most closely
related?

a. 5 & 6

b. 6 & 7

1. Which
organisms are
most closely
related?

a. 5 & 6

b. 6 & 7

Multiple Choice

Which organism is the common ancestor for just 6, 7, & 8?

• A

• B

Which organism is
the common
ancestor for just
6, 7, & 8?

3. What is the
common ancestor
for all organisms
in this cladogram?

A

B

C

Multiple Choice

What is the common ancestor for all organisms in this cladogram?

• A

• B

• C

3. What is the
common ancestor
for all organisms
in this cladogram?

A

B

C

Which organisms
have a large brain?

Binocular vision,
opposable thumbs

Color vision

Much larger brains

Bipedal,
language

Multiple Select

Which organisms have a large brain?

• Lemur

• Baboon

• Chimpanzee

• Human

Which organisms
have a large brain?

The chimpanzee and
human.

Binocular vision,
opposable thumbs

Color vision

Much larger brains

Bipedal,
language

Which organism
shares the most traits
with humans?

Binocular vision,
opposable thumbs

Color vision

Much larger brains

Bipedal,
language

Multiple Select

Which organism shares the most traits with humans?

• Lemur

• Baboon

• Chimpanzee

• Human

Which organism
shares the most traits
with humans?

The only trait it does
NOT share it being
bipedal and having a
language.

Binocular vision,
opposable thumbs

Color vision

Much larger brains

Bipedal,
language

What trait does a
baboon have that a
lemur does not?

Binocular vision,
opposable thumbs

Color vision

Much larger brains

Bipedal,
language

Multiple Choice

What trait does a baboon have that a lemur does not? 

• Binocular vision, opposable thumbs

• Color vision

• Much larger brains

• Bipedal, language

What trait does a
baboon have that a
lemur does not?

Binocular vision,
opposable thumbs

Color vision

Much larger brains

Bipedal,
language

What traits separate
humans from all other
primates in the
diagram?

Binocular vision,
opposable thumbs

Color vision

Much larger brains

Bipedal,
language

Multiple Choice

What traits separate humans from all other primates in the diagram?

• Binocular vision, opposable thumbs

• Color vision

• Much larger brains

• Bipedal, language

What traits separate
humans from all other
primates in the
diagram?

Binocular vision,
opposable thumbs

Color vision

Much larger brains

Bipedal,
language

Evolution

Embryology

Essential Question

Do organisms Evolve?
(Do organisms change over time?)

There are three main pieces of evidence
that scientists use to prove evolution.

● Fossil evidence
● Comparative anatomy
● Embryology

Evolution

(Embryology)

Embryology

(study of embryos)

Organisms that are closely related may also have

physical similarities before they are even born!

You will:

● Compare embryos for evidence of evolution

● Cite one piece of embryology evidence that

supports evolution.

Embryo

em·bry·o

noun

an unborn or unhatched
offspring (baby) in the first
processes of
development.

Anatomy of an
Embryo
(parts)

Gills

Eye

Tail

Which one of these is a human embryo?

Having trouble? They all look a lot a like. Which is the
point. All mammals (including humans) start this way.

Move on to the google form Evolution
Embryology assignment on the classroom.

This assignment has no wrong multiple
choice answers. So don’t go backwards! It
won’t hurt your score and it’s part of the
fun to see how wrong or right you were!

Finish and submit the

Embryology Assignment before

moving on!

Even though these are
embryos for very
different creatures, from
fish to tortoises to
humans, they are all
almost identical at their
starting stage: an
embryo.

Each one has gills, eyes,
and a tail as an embryo,
even if they do not have
all of those features by
the time they are born.

After all, we don’t have
gills now do we?

This gives additional
evidence that all
organisms had to have
common ancestors at
some point in the past.
When the first life forms
on Earth evolved, they
were the base from which
all other creatures
evolved.

Fossil Evidence

We don’t see today’s
animals in the fossil
history because they
didn't exist back then.
We do see similar
fossils showing that
they changed over
time.

Comparative
Anatomy

We see similar bones
and layouts in animals
that seem very
different; for example,
humans and bats. The
fact that animals share
similar bone structures
show that they had a
common ancestor long
ago.

Embryology

Every organism’s
embryos (first stages of a
baby) has gills, eyes, and
a tail regardless of
whether or not they have
all those features when
born. Humans obviously
lose the gills and tail in
development. But this is
further evidence that we
all evolved from the same
common ancestor.