Analogous Structures

NC L.8.4 Evidence of Evolution

Part 2

Regents Biology

But don’t be fooled by these…

▪ Analogous structures

◆ look similar

▪ on the outside

◆ same function

◆ different structure & development

▪ on the inside

◆ different origin

◆ no evolutionary relationship

Solving a similar problem with a similar solution

How is a

bird

like a bug?

What are Analogous Structures?

• Structures that are made differently, but have the same function.

• Examples: Wings of a bug, bird, and a butterfly.

Multiple Choice

a=Ana is the prefix for not. Analogous structures are not

• related by form

• related by function

• important to evolution theory

Multiple Choice

Bird wings and butterfly wings are an example of

• Homologous structure

• Analogous structure

• Mimicry

• Camoflague

Regents Biology

Analogous structures

▪ Dolphins: aquatic mammal
▪ Fish: aquatic vertebrate

◆ both adapted to

life in the sea

◆ not closely related

Watch the

tail!

Multiple Choice

Shark fins and dolphin fins are examples of analogous structures.

• True

• False

Multiple Choice

Why is the wing of a bat and wing of a bird considered a analogous structure?

• They have similar structure and similar function

• They have similar structure but different function

• They have different structure but similar function

Multiple Choice

Structures with the same anatomical make up but different functions is evidence that those structures came from

• the same ancestor because structures come from our DNA

• Different ancestors because structures come from our RNA

• the same ancestors because they are used in the same way

Regents Biology

Vestigial organs

▪ Structures that are reduced in size and

have lost all or most of their original
function.

Why would whales have
pelvis & leg bones if they
were always sea creatures?

Because

they

used to
walk on

land!

Regents Biology

Vestigial organs

▪ Structures on modern animals that have

no function

◆ remains of structures that were functional

in ancestors

◆ evidence of change over time

▪ some snakes & whales have pelvis bones &

leg bones of walking ancestors

▪ eyes on blind

cave fish

▪ human tail bone &

appendix

Multiple Choice

• Homologous

• Vestigial

• Analogous

Regents Biology

3. Comparative embryology

▪ Animals with backbones develop similarly

▪ During development, all vertebrates have a tail and paired
pharyngeal pouches.

-- In fish and amphibian larvae, the pouches become gills.
-- In humans, the pouches becomes the middle ear; tonsils, & glands

all vertebrate embryos have a “gill
pouch” at one stage of development

Multiple Choice

An organism in its early stage of development.

• an infant

• a calf

• a cell

• an embryo

Multiple Choice

What can we discover by viewing embryos of different species?

• How close they are related in terms of evolution

• What they will look like as adults

• Any vestigial structures that are present

• The average age that they can live to.

Regents Biology

4. Molecular record

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Comparing DNA & protein structure

◆ everyone uses the same genetic code!

▪ DNA sequences show how closely related 2

organisms are to each other.

▪ compare common genes
▪ compare common proteins

number of amino acids
different from human
hemoglobin

Multiple Choice

The closest evolutionary relationship most likely exists between the....

• human and gorilla

• horse and zebra

• human and chimpanzee

• chimpanzee and gorilla

Regents Biology

Building “family” trees

Closely related species are branches on the tree —
coming from a common ancestor

Regents Biology

5. Biogeography

▪ the study of the geographical distribution of living things
▪ The distribution of fossils show that the continents were

once joined together.

▪ Animals living in the same area evolve to have similar

traits.

Regents Biology

Multiple Choice

What is is the study of how and why plants and animals live where they do?

• Evolution

• Adaptive Radiation

• Biogeography

• Biogeology

Multiple Choice

Comparing DNA sequences shows___.

• How closely related organisms are

• Traits that can become available

• Evolution is not real

• That organisms have evolved from several different organisms.

Poll

How much DNA do you think humans and chimpanzees share?

• 20%

• 60%

• 80%

• 99%