Transcript Activity 101: Birds of a Feather?

Activity 101: Birds of a
Feather?
Challenge How does Natural
Selection help explain the
extinction of the dodo bird and
the success of the common
pigeon?
Getting Started
O Remember in our first activity, we were
introduced to the idea of extinction and the
possibility that human hunting contributed to
the mammoth’s demise.
O This last activity revisits some of the ideas
raised in the first activity, providing you an
opportunity to reflect upon and apply the
understandings of evolutionary process and
history that you have acquired during our unit.
Read the intro on page 56.
• There is a lot of diversity in
every point in life’s history!
• Yet, every species becomes
extinct eventually and all
the species that exist today
are descended from a
relatively small number of
earlier species!
• In fact, there is probably a
single common ancestor for
every species alive today –
a Bacterial Species!!!
Reasons for Extinction:
 Environmental Change
 Competing Species
 Habitat Loss
 Disease
 Human activity
Doing the Activity
O Use Student Sheet 101.1 “Three-Level
Reading Guide: Birds of a Feather?” to
guide you as you follow the reading
on pages 57-59
O When you are done, Answer Analysis
Questions: 1, 2, 4 and 5b (Use the
Discussion Web for 5b!)
Variation?
What would Darwin Say?
Dodo Bird
Common Pigeon
Analysis #1
O Without human contact, the pigeon would have
remained a wild species.
O It could have been successful, but because of
the limited range of the wild species, it would not
have had nearly as large a population or as wide
a range as the feral pigeon currently has.
O Without human contact, the dodo may have
thrived. But, its adaptation did not make it well
prepared for climatic change or changing
ecological conditions.
Analysis #2
O The evolution of feral pigeons
could be described as speciation
in process, but one that began
through hybridizaton.
Analysis #4
O You should Disagree with the friend.
O The reason the Dodo went extinct was not that is was
poorly adapted but rather that it was too well adapted!
O When introduced species/predators were introduced,
dodo populations declined rapidly.
O The process of natural selection is slow and unable to
produce a modified species of dodo before the last dodo
died.
O If there had been more time, and a larger dodo
population, the new conditions might have produced a
population that could survive and co-exist with the
invaders.
Should dodos be re-created?
YES
NO