Download Evolution scenarios

EVOLUTION
REVIEW
Evidence for Evolution
•What do we use in order to determine
evolutionary relationships?
•Fossil Record
•Anatomical Evidence
•Molecular Evidence
•Embryological Evidence
Evidence for Evolution
•Fossil Record
Evidence for Evolution
•Anatomical Evidence
• Homologous Structures – Same anatomy, different function
• Conclude close evolutionary relationships
Evidence for Evolution
•Anatomical Evidence
• Analogous Structures – Different anatomy, same function
• Not closely related, do NOT share a recent common ancestor
Evidence for Evolution
•Anatomical Evidence
• Vestigial Structures – No longer serve a purpose
• All us to draw conclusions regarding the past
Evidence for Evolution
•Molecular Evidence
• The more similar the molecules (DNA, protein, etc),
the closer the relationship.
Evidence for Evolution
•Embryological
Evidence
• The more similar the
embryo in early
development, the closer
the relationship.
Let’s Review!
•Directional Selection
•Selection towards a single direction
•Disruptive Selection
•Selection against the mean (middle)
•Selection towards extremes
•Stabilizing Selection
•Selection towards the mean (middle)
•Selection against extreme
Do you get it?
Evolution Scenarios
A. Directional Selection B. Disruptive Selection C. Stabilizing Selection
Evolution Scenarios
Evolution Scenarios
A. Directional Selection B. Disruptive Selection C. Stabilizing Selection
Evolution Scenarios
Evolution Scenarios
A. Directional Selection B. Disruptive Selection C. Stabilizing Selection
Evolution Scenarios
That brings us to speciation…
• Speciation: the creation of a new species as a result
of evolution.
• How do you know when you have a new species?
• They can no longer reproduce!
• Rate of Speciation Theories
• Gradualism
• Evolution occurs slowly and gradually, with very small
changes accumulating over a long period of time until a new
species develops.
• Punctuated Equilibrium
• Evolution occurs in short, rapid bursts of change followed by
long period of no change.
Do you get it?
A. Gradualism
B. Punctuated Equilibrium
Do you get it?
A. Gradualism
B. Punctuated Equilibrium
Let’s Switch Gears…Patterns of Evolution
• Divergent Evolution
• Related species becoming more and more
different due to living in different types of
environments
• Convergent Evolution
• Unrelated species becoming similar due to
living in similar types of environments
• Coevolution
• The simultaneous evolution of two species due
to their close interaction/relationship
Patterns of Evolution Scenarios
A. Convergent Evolution
B. Divergent Evolution
C. Coevolution
•In tropical regions bats visiting flowers to eat
nectar. The fur on the bat's face and neck
picks up pollen, which the bat transfers to the
next flower it visits. Bats that feed at flowers
have a slender muzzle and a long tongue with
a brushed tip. These adaptations aid the bat in
feeding. Flowers that have coevolved with
bats are light in color. Therefore, bats, which
are active at night, can easily locate them. The
flowers also have a fruity odor attractive to
bats.
Patterns of Evolution Scenarios
A. Convergent Evolution
B. Divergent Evolution
• Adaptive Radiation of marsupials in Australia
C. Coevolution
Patterns of Evolution Scenarios
A. Convergent Evolution
B. Divergent Evolution
• This picture shows four
different animals from
around the globe. They
may look similar, but it’s
not because they are close
relatives. Instead, they’ve
evolved similar adaptions
because they occupy
similar niches – dining on
ants, hunting in the high
grass or swimming in the
dark – although their
evolutionary origins are
quite different.
C. Coevolution