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EVIDENCE OF EVOLUTION
Evidence of Evolution
•
Scientist who study
fossils focus on more
than the fossil itself.
•
They also think about:
•
Its age
•
It’s location
•
and what the
environment was like
when the organism it
came from was alive
Evidence of Evolution
•
Darwin hypothesized that at some point in time the
species from the South American mainland had migrated
to the Galapagos Islands.
•
Biogeography: The study of the distribution of
organisms around the world.
•
One clear example : Darwin’s finches
Evidence of Evolution
•
Developmental similarities:
•
Notochord, Dorsal nerve cord,Pharyngeal
arches
Evidence of Evolution
•
Homologous Structures: Features that are similar in
structure but appear in different organisms and have
different functions.
•
Strong evidence for common descent.
Evidence of Evolution
•
Analogous
Structures: Structures
that perform a similar
function but are not
similar in origin.
•
Ex: Bird wings and
Insect wings.
•
Not common descent.
Evidence of Evolution
•
Vestigial Structure:
remnants of organs or
structures found in an early
ancestor that no longer
serve a useful function or
may now serve a different
function.
•
Ex: The wings of an ostrich
or the appendix in humans.
•
Considered the most
important way to
demonstrate how evolution
works.
•
EVOLUTIONARY BIOLOGY
TODAY
Paleontology: the study of
fossils or extinct organisms,
continues to provide new
information and support
current hypothesis about
how evolution occurs.
•
Fossil record is not
complete because most
living organisms do not
create fossils.
•
No fossil evidence that
contradicts evolution.
EVOLUTIONARY BIOLOGY
TODAY
•
Molecular and genetic evidence:
•
1.) DNA Sequence Analysis- The more related two organisms are,
the more similar their DNA will be.
•
2.)Pseudogenes- Genes that no longer have a function but are
carried along with DNA still.
•
3.) Protein Comparisons: Cells from different species that have the
same proteins most likely come from a common ancestor.
•
4.) Homeobox Genes: Genes that control the development of
specific structures.