ANTH 1000 - Ch. 6 Flashcards
macroevolution
evoluation above the species level
speciation
the process of forming new species
isolating mechanism
a factor that separates bredding populations, thereby preventing gene flow, creating divergent subspecies and ultimately (if maintained) divergent species
cladogenesis
speciation through a branching mechanism whereby an ancestral population gives rise to two or more descendant populations
heterochrony
change in the timing of developmental events that is often responsible for changes in the shape or size of a body part
homeobox gene
a gene responsible for large-scale effects on growth and development that are frequently responsible for major reorganization of body plans in organisms
punctuated equilibria
a model of macroevolutionary change that suggests evolution occurs via long periods of stability or stasis punctuated by periods of rapid change
anagenesis
a sustained directional shift in a population’s average characteristics
derived
characteristics that define a group of organisms and that did not exist in ancestral populations
ancestral
characteristics that define a group of organisms that are due to shared ancestry
convergent evolution
in biological evolution, a process by which unrelated populations develop similarities to one another due to similar function rather than shared ancestry
continental drift
according to the theory of plate tectonics, the movement of continents embedded in underlying plates on the earth’s surface in relation to one another over the history of life on earth
adaptive radiation
rapid diversification of an evolving population as it adapts to a variety of available niches
preadapted
possessing characteristics that, by chance, are advantageous in future environmental conditions
homeotherm
an animal that maintains a relatively constant body temperature despite environmental fluctuations
isotherm
an animal whose body temperature rises or falls according to the temperature of the surrounding environment
k-selected
reproduction involving the production of relatively few off-spring with high parental investment in each
r-selected
reproduction involving the production of large numbers of offspring with relatively low parental investment in each
arboreal hypothesis
a theory for primate evolution that proposes that life in the trees was responsible for enhances visual acuity and manual dexterity in primates
visual predation hypothesis
a theory for primate evolution that proposes that hunting behavior in tree-dwelling primates was responsible for their enhanced visual acuity and manual dexterity
molecular clock
the hypothesis that dates divergences among related species can be calculated through an examination of the genetic mutations that have accrued since the divergence
