Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
22 Cards in this Set
- Front
- Back
|
speciation |
the process by which new species arise, either by transformation of one species into another, or by the splitting of one ancestral species into two descendant species |
|
|
sympatric |
the differentiation of populations withing a common geographic area into species |
|
|
subspecies |
a geographically-defined population or group of populations withing a single species that has distinctive characteristics |
|
|
gene pool |
all the alleles present in a species |
|
|
biological species concept |
the concept that defines species as groups of populations that have the potential to interbreed and that are reproductively isolated from other groups |
|
|
reproductive isolating mechanism |
any barrier that prevents genetic exchange between species |
|
|
prezygotic isolating mechanism |
a type of reproductive isolation in which the formation of a zygote is prevented; these mechanisms may range from physical separation in different habitats to gametic in which gametes are incapable of fusing |
|
|
postzygotic isolating mechanism |
a type of reproductive isolation in which zygotes are produced but are unable to develop into reproducing adults; these mechanisms may range from inviability of zygotes or embryos to adults that are sterile |
|
|
pheromone |
chemical substance released by one organism that influences the behavior or physiological processes of another organism of the same species. Some pheromones serve as sex attractants, as trail markers, and as alarm signals |
|
|
cladogenesis |
the process by which one ancestral species becomes divided into two descendant species |
|
|
reinforcement |
in speciation, the process by which partial reproductive isolation between populations is increased by selection against mating between members of the two populations, eventually resulting in complete reproductive isolation |
|
|
allopatric |
the differentiation of geographically isolated populations into distinct species |
|
|
polyploidy |
condition in which one or more entire sets of chromosomes is added to the diploid genome |
|
|
autopolyploid |
a polyploid organism that contains a duplicated genome of the same species; may result from a meitotic error |
|
|
allopolyploid |
a polyploidy organism that contains the genomes of two or more different species |
|
|
adaptive radiation |
the evolution of several divergent forms from a primitive and unspecialized ancestor |
|
|
key innovation |
a newly evolved trait in a species that allows members to use resources or other aspects of the environment that were previously inaccessible |
|
|
character displacement |
a process in which natural selection favors individuals in a species that use resources not used by other species which results in evolutionary change leading to species dissimilar in resource use |
|
|
gradualism |
the view that species change very slowly in ways that may be imperceptible from one generation to the next but that accumulate and lead to major changes over thousands or millions of years |
|
|
stasis |
a period of time during which little evolutionary change occurs |
|
|
punctuated equilibrium |
a hypothesis about the mechanism of evolutionary change proposing that long periods of little or no change are punctuated by periods of rapid evolution |
|
|
mass extinction |
a relatively sudden, sharp decline in the number of species; for example, the extinction at the end of the Cretaceous period in which the dinosaurs and a variety of other organisms disappeared |
