Download Convergent and Divergent Evolution

Ecology and Evolution: the
Origin of Biodiversity
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Divergence along the tree of life
Grizzly bears and polar
bears split from their
common ancestor only
about 500,000 years
ago.
An ancestral bear
evolved giving rise to
many species of bear,
which occupy many
different niches – in
many different
habitats.
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Wild Canine Adaptations
The canine lineage, in terms of
its evolution has been very
successful.
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An Artiodactyl Family Tree
Notice the inclusion of whales
on the artiodactyl family tree.
Fossil, anatomical, and DNA
research has unequivocally
shown that whales are a
highly modified form of twotoed, hoofed, mammal.
Their closest “terrestrial”
relative is the hippo.
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Convergent Evolution: very different
species filling the same niches
Sometimes convergent
evolution modifies
different body parts to
look the same and
perform the same
function.
In this case, insect wings
were derived from
insect-exoskeleton,
while bird and bat wings
were derived from
forelimbs with an
internal skeleton.
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Convergent Evolution: very different
species filling the same niches
In the case of bats and
birds, the same forelimb
structures were
modified independently
for flight in very
different groups
(mammals and birds).
As you can see, bats fly
with the tips of their
fingers while birds fly
with their shoulders and
arms.
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Convergent Evolution of Mammals
Marsupial and
placental
mammals, case
studies in
convergent
evolution.
The same or
similar niches
produce great
similarities in
very different
species.
Example of two
species cannot
occupy the same
niche.
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Convergent Evolution of Marine
Predators
The Tree of Life contains many remarkable examples of convergent
evolution, which attest to the great power of natural selection to adapt
different organisms to similar environments.
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What do they mean?
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•
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What is speciation mean?
What does convergent evolution mean?
What does the tree of life illustrate?
How does divergence lead to new species (this
is speciation)?
• How do you think they are a product of
habitat and niche?
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