Download DNA - Tipp City Exempted Village Schools

Biogeography
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Species are most closely
related to those near
them
Rain forests in different
parts of the world have
very different species
Species tend to be very
similar to the fossils found
in there area – but with
some changes
Fossil Records
The age of
different fossils
matches what we
would expect
 I.e. we find that
brain size has
increased over
time
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Comparative Anatomy
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The anatomies of
related species are
similar, even if they are
used differently
i.e. bones of humans,
cats whales and bats
are similar
Homologous Structures
Vestigial Organs
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Leftover body parts
that do not help a
species
i.e. whales still have
pelvises and remnants
of leg bones
These structures serve
no purpose in the
modern animal
Comparative Embryology

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Similar species develop in very similar ways
Especially early in development, before lots of
specialization has occurred
Molecular Biology

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Closely related species
are closely related in
their genetic codes
Also supports idea that
all species are relatedall species share DNA
and some proteins
The “Theory” of Evolution
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The closely related
nature of all life is
really not debatable
Natural selection is
really the theory
Well documented
and thoroughly
supported- like the
“Theory” of Gravity
Macroevolution and Speciation
•Microevolution
explains how
populations can
change over time
•But how do new
species or other
taxonomic groups
arise?
Geographic Speciation
•The formation of new species usually occurs
when 2 populations are separated and evolve
differently
•Eventually the species have changed so much
that they can no longer reproduce
Homology vs. Analogy

Homology means two
features are similar
due to ancestry

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Wings in bats,
arms in humans,
fins in whales
Called homologous
structures
Caused by divergent
evolution
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Analogy is when two
organisms have
similar features but
are not closely related
Wings in bats and
birds
Caused by
convergent
evolution
Evolved the same
solution
Embryology Analysis
Advantages
Disadvantages
•Allows us to see
similarities even
when adults of the
species look very
different
•Often similarities are
lost later in
development
• i.e. We have gills
early on in
•I.e. reptiles and birds development
look more closely
related