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.
5 min
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
3 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!!!!
2 min
2, 1, 5, 7, 9, 3, 4, 8, 6
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?
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
__________.
•
change
fish
reptile
species
bird
variations
complex
gaps
Fossil Record shows:
arise
gradual
• 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
complete
bottom
extinct
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.
continental
geographical
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.
2.
3.
4.
5.
One simple specie
Island breaks away –
species A evolves into
species B
Island breaks away
again – species B
evolves into species C
Geographic isolation
occurs because of
mountain ranges –
species C is separated
leading to a new
species D
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.
Today
Gibbon
Orangutan
Chimp
5 MYA
Human
Gorilla
D
C
10 MYA
B
15 MYA
A
MYA= Millions of years ago
Above image modified from
http://www.learner.org/channel/courses/biology/textbook/humev/humev_3.ht
ml
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.
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.