7A – Evidence of Evolution

Fossil Evidence & Biogeography

7A analyze and evaluate how evidence of common ancestry among groups is provided by

the fossil record, biogeography, and homologies, including anatomical, molecular, and

developmental.

In:

• How does fossil evidence gives us clues to how organisms from the past are related to organisms from today?

• Write your answer on the paper

• Discuss with partner

• Discuss as a class

5 min

Dating the Fossil Record

• You have received nine rock samples from a paleontologist in California.

• Your job is to arrange the samples in order from oldest to youngest according to their fossil content .

• Results from absolute dating methods will not be available from a laboratory for several weeks, and the paleontologist needs the information immediately.

• Begin with Sample 2. They are the oldest rocks.

You have 3 minutes!!!!

3 min

2 min

Dating the Fossil Record

• Discuss with your partner or group

• Describe what might have happened to some of the organisms from the beginning to now.

• Develop a hypothesis of how some of the species changed or became extinct over time?

• Do you have any evidence?

2 min

Dating the Fossil Record

• Discuss with your partner or group

1. Which one of the species is the common ancestor? Which sample can we find it in?

2. Which one of the species is the modern species? Which sample can we find it in?

3. Does the modern species resemble the ancient common ancestor?

2 min

Evolution is a Theory – Just like Gravity!

• Evolution - gradual change in the genetic makeup of a population through successive generations .

• Theory - a well tested explanation supported by evidence

Description

• Similarities of __________ in the fossil record reflects that organisms have a common ancestor.

• _______________ in bone structure of specific species shows _____________ over time.

• Fossil record has revealed links between large groups of organisms such as from _________ to __________ and reptile to __________.

•

variations

species

fish

change

reptile

bird

Fossil Record shows:

• Relative ____________ of a species

• How species found in the ________________ layers are very ___________ from what is in the top layer

• Species today are more ______________ (cell structure, DNA)

• That when new species _____________, others become ____________

• _________________ evolution in species over time

• _________ in the timeline and is not __________.

age different bottom

complex arise

extinct

gradual gaps

complete

Evolution of the Horse

Biogeography

Biogeography Simulation

• See lesson plan for directions

In:

• Why are some species only found in some parts of the world and not others?

• Write your answer

• Discuss with partner

• Discuss as a class

Description: Biogeography

• the study of _________________________ isolation and _____________________ drift.

geographical continental

Species

• a group of individuals that actually or potentially interbreed (sexually) in nature

Speciation

• event that produces two or more separate species

• Click here for the story

How does one species become two species?

• Reproductive isolation is the most common cause.

• For example, if some flies land on an island with no flies they may evolve into one or more new species that are different from the species where they originally came from.

Diversity

• Name some animals that inhabit the austin-round rock area.

• Aka: biodiversity

• the different varieties of organisms inhabiting a particular region

Geographical Isolation

• Describe what you think this might mean to your partner.

• Species are separated due to an event or natural barrier – leads to speciation

Biogeography

• (clockwise from top) a chameleon, an aye aye, a fossa, and a baobab. All are native to Madagascar.

• Why is Madagascar home to so many unique plants and animals?

Madagascar then….

Madagascar then & now…

Madagascar…..now!

• Rarest species on earth found no where else

Speciation: From 1 specie to 5.

1. One simple specie 2. Island breaks away –

species A evolves into species B

3. Island breaks away again – species B evolves into species C

4. Geographic isolation occurs because of mountain ranges – species C is separated leading to a new species D

5. Island breaks away again – species D evolves into species E.

From 1 specie to 5.

1. Who is the ancestral species?

2. Is the ancestral species still alive today? How?

3. Are these species related to each other?

4. What’s another way new species can show up in an isolated area?

The following mammals did not exist in Madagascar but instead they used natural rafts to get to the island. (At least in theory)

So if you had ticket, you had a ride

Why don’t lions, elephants, apes, antelopes, & zebras exist in Madagascar?

Any animal can move to another location as long as it can find a way.

Out:

• Describe how evidence of common ancestry is provided by biogeography. Use the terms: common ancestor, species, speciation, diversity, geographic isolation, continental drift.

•

• Predict: From what you have learned about the fossil record and biogeography, predict what happened to the Hawaiian Islands and to the number of species over time.

Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

Based on DNA evidence, scientists have constructed this phylogeny of primates.

1.At which node is the common ancestor of chimps and orangutans?

2. To which primate are humans most closely related? How do you know?

3.At which node is the common ancestor of all primates? How many years ago did it exist?

4.Is it accurate to say that humans came from chimps? Explain.

Gibbon Orangutan Chimp Human Gorilla

15 MYA

5 MYA

10 MYA

Today

A

D

C

B

MYA= Millions of years ago Above image modified from http://www.learner.org/channel/courses/biology/textbook/humev/humev_3.html