Download Other Evidence for Evolution (includes living fossils)

Evidence for
Evolution
1- Fossils of now-extinct
animals & plants
2
LIVING
FOSSILS
Survivors from plant and animal
families long extinct now.
COELACANTH
Deepwater fish, found in 1938 by
Indian fishermen.
Fossils of Coelacanth
date back to the
Silurian period.
STURGEONS (Sp: esturion)
Common, seen in many continents
FRILL SHARK (Filmed in 2006 off Coast of Japan)
2- Vestigial Structures
Cave fish “eyes”
Ostrich wings
Snake legs
The coccyx (tailbone): a
vestigial structure in humans
16
WISDOM TEETH: No longer needed... from the times
our ancestors had a vegetarian diet.
APPENDIX: A structure that used to house bacteria
capable of digesting cellulose.
13 RIBS: Humans have 12 ribs/side... but 8% of humans
have 13 ribs, like chimps and gorillas.
NICTATING MEMBRANE,
“Third eyelid”. Common
in birds, reptiles &
amphibian. Protects the
eye. In humans reduced
to a thin membrane by
the tear duct.
What are vestigial structures?
Remains of once-used organs / structures,
no longer in use.
Best
example:
whale leg
bones
3- Homologous structures
Show a COMMON ANCESTOR
Have evolved for different function.
Shoulder – arm bone assembly
first seen in late Devonian
fish fossils, then in early
land-dwelling amphibian
fossils.
Ex: Humerus bone.
4- Similarities in early embryos
Whales (Top)
Human (bottom)
Closely related animals have very similar early-stage embryos. It’s only when
species-specific developmental genes are expressed that differences appear.
Related organisms have
similar early embryos.
The diagram below shows stages in the the embryonic development of
three different vertebrate species. The similarities in structure provide
evidence that these three species most likely...
a) live in the same type of
environment.
b) occupy the same ecological
niche.
c) undergo asexual reproduction.
d) descend from a common
ancestor.
5- Similar biochemistry
So many oh-so important
molecules found in every
single living organism...!
Related organisms have similar
proteins & enzymes, use similar
molecules, show similar DNA
sequences….
6- Current observations &
Predictions
Best example: antibiotic resistance