Chapter 4 Flashcards
(20 cards)
Phylogeny
-a visual representation of the evolutionary history of populations, genes, or species
No currently existing species is
-ancestral to any other
Clades are
-monophyletic groups
Monophyletic groups
Include the common ancestor and all the descendants
Paraphyletic group
Includes the con on ancestor and some but not all of the ancestors descendants
Polyphyletic group
-does not include the common ancestor of the group
The only groups that are named are
Monophyletic
Clades are determined by
-synapomorphies
Plesiomorphy
-a trait shared by all the members of a group, making it useless for determining evolutionary relationships
Synapomorphy
-a trait shared by two or more groups and the common ancestor of the groups
All synapomorphies are ________ but not all homologies are _________
-homologies
-synapomorphies
Linnaeus used _________ to make phylogenies
-physical traits
Homoplasy
-character state similarity not due to common ancestry
-convergent evolution
Convergent evolution
-independent evolution of similar trait, basically the same as homoplasy
What is an example of a homoplasy?
-cats, hyenas, and otters having an absent first premolar
Parsimony
-simplest explanation is most likely correct
Phylogenies generate
-hypotheses
How did feathers evolve before flight?
-natural selection co-opts a trait for a new function
Fossil record should document transition to unique human traits such as
-bipedality
-larger brain size
-smaller canine teeth
Human transition to bipedality
-position of foremen magnum
-weight bearing stance
-short, stiff toes
