phylogeny

evolutionary history showing the relatedness of a group

taxa

any groups of organisms

node

point where branch splits + common ancestor from which descendent species diverged

phylogenetic tree

shows evolutionary history of groups and organinsms

classification

reflects understanding of phylogenetic relationships

clade '(monophyletic)

group of organisms that include a common ancestor and all its descendants

sauropids

group of birds and traditional reptiles

paraphyletic

includes some but not all of descendants of a common ancestor

cladogram

type of evolutionary tree based on clades

characters

anatomical, physiological, or molecular features that makeup organisms

shared characters

characters sometimes present in two or more groups of organisms

homology

similarity that results from shared ancestry

analogy

similarity that results from convergent evolution

echolocation

to locate objects in their surroundings by emitting sounds and interpreting patterns of echoes

prestin

hair cells of mammalian ars and is involved in hearing ultrasonic frequencies

derivable character

evolutionary innovation in ancestors of horses and donkeys

synapomorphy

novelty arises in common ancestor of two taxa

outgroup

taxon whose common ancestor with the group of interest is older than common ancestor of group interest

molecular data

provides wealth of characters that complement other types of info. in building tree

biological species concept (BSC)

species are groups of actually or potentially interbreeding populations that are reproductively isolated from each other such groups

morphospecies

members of the same species usually look alike

niche

complete description role the species plays in their environment and of its abiotic and biotic environments

reproductive isolation

inability of diff species to produce viable, fertile offspring

prezygotic

factors act before fertilization + prevent fertilization

postzygotic

after fertilization + prevent fertilzed egg from devloping

speciation

process by which new species are produced

divergent evolution

2 pop. of organisms become genetically and physically diff from each other

allopatric

populations geographically separated from each other

dispersal

some individuals colonize a distant place

vicariance

geographic barrier arises within single pop. separating it into 2 or more isolated pop.

sympatric

pop. that are in the same geographic location

adaptive radiation

unusually rapid evolutionary diversification in which natural selection accelerates the rates of both speciation and adaptation

gradualism

species change slowly over time

punctuated equilibrium

model in which there are periods if relatively little change