ANT Exam 2- Chapter 5 P1

homologies

similarities between organisms based upon descent from a common ancestor

analogies

similarities between organisms based strictly on common function, with no assumed common evolutionary descent

homology example

5 digits on mammals

analogy example

bat and butterfly wings

ancestral (primitive)

characteristics inherited by a group of organisms from a remote ancestor, therefore not useful in distinguishing the descendant groups

ancestral example

5 digits in primates - this characteristic is shared in most mammals (dogs, cats) so not distinctive of primates

derived (modified)

characteristics modified from the ancestral condition, and therefore distinctive or a particular evolutionary lineage

derived example

primates have nails instead of claws which distinguishes them from other mammals

Paleozoic

era 540-252 mya, life first flourishes on earth, starts in sea, plants become more widespread, vertebrates first colonize land

Mesozoic

era 252-66 mya

what happened to the dominant animals

Pangea splits apart, dinosaurs dominant the land and ends in extinction event, mammals and flying dinosaurs survive

contiental drift and evolution

when continents split and come together, plant and animal distribution changes

continental drift- South America, Africa and Asia

ancestors of primates

continental drift- Africa and Asia only

Great Apes, South America splits before they evolved

Cenozoic

era after 66 mya to the present, mammals dominate the landscape

adaptive radiation

when dinosaurs became extinct at the end of the Mesozoic Era, mammals survive and are able to rapidly expand due to the absence of other life and range of habit space