Module 1 Flashcards
Ardipithecus ramidus
Where do we come from?
fossils to 3.8BYA
Approx. 600 MYA multicellular organisms
comparative anatomy definition
the study of the evolution of the body systems
first teacher of comp. anatomy
Agassiz
Belons book of birds
George cuvier
from a small part of an organism, the whole can be deduced
phylogeny
- a statement of relationships
- evolutionary history
fossils
- allow for better view of evolution
- molecular clock
- estimate when common ancestors might have lived
analoge
correspondence in function, or position b/w organs of dissimilar evolutionary origin or structure
“same function, different origin”
homology
correspondence in evolutionary origin
“same origin, not necessarily same function”
convergence
two unrelated organisms evolving the same structure
- ex: bird wings and bat wings
parallelisms
two sister species evolve same structure independetly
- almost impossible to test
reversals
change to less derived state
- development of the collar bone in primates (small or absent in most other mammals)
phylogeny is expressed in a branching diagram
phylogenetic tree
branch =
lineage
node =
hypothetical common ancestor
clostest relative (sister group)
go to first node and read all taxa above this point
monophyletic group
group consisting of all descendents of the group’s most recent common ancestor
paraphyletic group
group consisting of the group’s most recent common ancestor, but not all descendents.
- bad, doesn’t represent evolution
polyphyletic group
group consisting of two or more groups, but not the group’s most recent common ancestor nor all of its descendents.
why are monophyletic groups the only good ones in taxonomy?
- non monophyletic groups says nothing about the group’s evolution
- naming paraphyletic groups is subjective
- from a proper taxonomy, you can almost recreate the phylogeny
apomorphy
derived characteristics
synapomorphy
shared derived characteristics
plesiomorphy
primitive characteristics
symplesiomorphy
shared primitive characteristics
