Ch3 + 4 Flashcards
divergent evolution of numerous related lineage within a relatively short time
Adaptive Radiation
retained with little or no change over long periods among the many descendants of an ancestor
conservative characters
superficially similar ft. are formed by different developmental pathways
convergent evolution (convergence)
return from an “advanced” or derived, character state to a more “primitive or ancestral state
Evolutionary reversal (reversal)
repeated change of a character in the same direction, either within a single lineage or,often, in many lineages indpendently
Evolutionary trend
new gene arises as a copy of a pre-existing gene, so that a single gene locus in an ancestor is represented by two loci in the descendant
gene duplication
process occurring repeatedly over evolutionary time
gene family
evolutionary change in the timing or rate of development events
heterochrony
independent evolution of a character or character state in different taxa
Homoplasy
acquisition of distinct identities by such modules (mosaic evolution)
individualization
evolution of different characters at different rates within the lineage
mosaic evolution
reducing the growth rate of somatic characters
neoteny
genes that diverge from a common ancestral gene by phylogenetic splitting at the organismal level
orthology
reproduces while retaining most of its larval characteristics
paedomorphosis
involve similar developmental modification that evolved independently
Parallel evolution (parallelism)
genes that originate from an ancestral gene duplication
paralogy
evolution of delayed maturity may result in reproduction at a larger size, asst. w/ the deve. of “hyper-adult” ft.
peramorphosis
cessation of growth at an earlier age
progenesis
proposed generalization that individual body size in animals tends to increase during evolution
Cope’s rule
a taxon, distinguished by derived character states, that has descended from an ancestral group that may bear a different name
Crown group
formed from geologist before Darwin. Not into the idea of evolution
geological time scale
a group of species that have evolved the same state in one or more characters and typically constitute a paraphyletic group relative to other species that have evolved further in the same direction
grade
a term for gradual evolutionary change in ft. over a long period of time
Phyletic gradualism
pattern of rapid evolutionary change in the phenotype of a lineage separated by long periods of little change;
Punctuated equilibria
alternating periods of slow and more rapid gradual change in a single lineage
punctuated gradualism (anagenesis)
est. ages of geological material and events by the decay of radio active elements
radiometric dating
absence of substantial evolutionary change in one or more character for some period of evolutionary time
stasis
descends from an ancestral grops
stem group
layers of sedimentary rock that were deposited at different times
strata
Homologous in two species if it has been derived from their common ancestor
Character state
