Evidence for Evolution
By
Diana L. Duckworth
Rustburg High School
Campbell County
Comparative Anatomy
http://encarta.msn.com/media_461553540_761554675_1_1/analogous_and_homologous_structures.html
Homologous Structures
Evidence of common ancestry –
same groups of bones.
Vestigial
Structures
Homologous bones or
organs that are no longer
functional
Humans – cocyx (tail
bone); appendix; ear
muscles; wisdom teeth;
body hair; eyebrows; eye
lashes; tonsils
http://www.iss.k12.nc.us/schools/shs/jmccartney/natsel.html
Homologous
Embryology
Early development is
same for many
organisms; evidence of
common ancestry.
http://apbio12007.blogspot.com/2007/09/evidence-of-evolution-by-natural.html
Fossil Evidence
• Excellent lineages of
– Horses
– Pigs
– Whales
• Two types of patterns visible:
– Gradualism – directional selection produces gradual
change over long time period
– Punctuated Equilibrium – rapid evolution in short
bursts separated by long periods of stasis
• Rapid evolution – directional or disruptive
selection
• Stasis – stabilizing selection
Horse evolution
Whale evolution
http://evolution.berkeley.edu/evosite/evo101/VIIAPaceevolution.shtml
http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/evolution/evolutionrev4.shtml
From one Class to Another
Mammal, adapted
for chewing & tearing
Mammal-like reptile
http://mgonline.com/iguana.html
Note differences in body position
Reptile, adapted for
gulping
http://www.talkorigins.org/faqs/comdesc/section1.html
http://bookingnwguides.com/BigGame/canada/lynxhuntingguidescanada.htm
From a
reptilian skull
to a mammallike reptile to a
mammalian
skull; well
documented
transitions in
fossil record.
http://www.bringyou.to/apologetics/p15.htm
Mammal-like reptiles;body Type –
reptile; skull mammalian
Internal structure of bones indicative of
endothermy – warm blooded.
http://faculty.plattsburgh.edu/thomas.wolosz/pre-dino.htm