Evolutionary Patterns Chapter 23 Flashcards
phylogenetic trees provide
hypotheses of evolutionary relationships
phylogenetics is the study of
evolutionary relationships among organisms & the classifications of organisms (taxonomy)
taxonomy allows for
hierarchical classification so we can effectively communicate info about features of each group
what lies at the heart of phylogenetics?
search for sister groups
the more recent a common ancestor, the __
more closely related the two groups are
a monophyletic group consists of
a common ancestor (not shared w/ any other species or group of species) & all its descendants
paraphyletic includes
some not all of the descendants of a common ancestor
polyphyletic
doesn’t include last common ancestor of all members
DKPCOFGS
domain kingdom phylum class order family genus species
how are phylogenetic trees made? on what basis?
comparing characteristics between organisms called character states
where do character states come from?
- common ancestor
- evolved in the 2 groups as an adaptation
homologous characters
similar b/c descent from common ancestor
analogous characters
characteristics that evolved independent of the 2 groups
cladistics
making a phylogenetic tree based on shared derived characteristics
using molecular data is more reliable because
the rate of evolution is held constant
why are fossils important?
calibrate phylogenies in terms of time
why does marine life have more fossils?
b/c more sedimentation
what do we use to determine age of a sample?
carbon dating. carbon-14 half life
we can understand the environment of fossils depending on
which kinds of rocks they are embedded in
lack of oxygen was when?
3 bya
pangea was when?
290 mya
what has altered the course of evolution?
rare mass extinctions
when was there a huge boom in animal diversity?
540 mya
___ came before large human brain
walking upright
