Chapter 3 Flashcards
**microevolution
A subfield of evolutionary studies that devotes attention to short-term evolutionary changes that occur within a given species over relatively few generations of ecological time.
**macroevolution
A subfield of evolutionary studies that focuses on long-term evolutionary changes, especially the origins of new species and their diversification across space and over millions of years of geological time.
–species
A reproductive community of populations (reproductively isolated from others) that occupies a specific niche in nature.
gene pool
All the genes in the bodies of all members of a given species (or a population of a species).
gene frequency
The frequency of occurrence of the variants of particular genes (i.e., of alleles) within the gene pool.
population genetics
A field that uses statistical analysis to study short-term evolutionary change in large populations.
polymorphous
Describes alleles that come in a range of different forms.
cline
The gradual intergradation of genetic variation from population to population.
–natural selection
A two-step, mechanistic explanation of how descent with modification takes place: (1) every generation, variant individuals are generated within a species due to genetic mutation and (2) those variant individuals best suited to the current environment survive and produce more offspring than other variants.
mutation
The creation of a new allele for a gene when the portion of the DNA molecule to which it corresponds is suddenly altered.
**gene flow
The exchange of genes that occurs when a given population experiences a sudden expansion due to in-migration of outsiders from another population of the species.
**genetic drift
Random changes in gene frequencies from one generation to the next due to a sudden reduction in population size as a result of disaster, disease, or the out-migration of a small subgroup from a larger population.
plasticity
Physiological flexibility that allows organisms to respond to environmental stresses, such as temperature changes.
adaptation
(1) The mutual shaping of organisms and their environments. (2) The shaping of useful features of an organism by natural selection for the function they now perform (see Chapter 2).
acclimatization
A change in the way the body functions in response to physical stress.
formal models
Mathematical formulas to predict outcomes of particular kinds of human interactions under different hypothesized conditions.
anagenesis
The slow, gradual transformation of a single species over time.
**phyletic gradualism
A theory arguing that one species gradually transforms itself into a new species over time, yet the actual boundary between species can never be detected and can only be drawn arbitrarily.
cladogenesis
The birth of a variety of descendant species from a single ancestral species.
**punctuated equilibrium
A theory claiming that most of evolutionary history has been characterized by relatively stable species coexisting in an equilibrium that is occasionally punctuated by sudden bursts of speciation, when extinctions are widespread and many new species appear.
species selection
A process in which natural selection is seen to operate among variant, related species within a single genus, family, or order.
**Sociobiology
School of thought that believed everything humans did could be traced back to their individual genetic makeup…
“Systematic study of the biological basis of all social behavior”
**Evolutionary Psychology
Like Sociobiology, but doesn’t think that natural selection has a bearing on human behavior patterns via genes in present day. Believe this was most significant millions of years ago when we split off from apes.
**Behavioral Ecology
Accepts the view that human adaptations depend on cultural learning rather than on genetic control, but insist that the cultural behavior human beings develop is closely circumscribed by the selectino pressures imposed upon us by the ecological features of the environments in which human populations have lived.
