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Biology 122 - Vocab 3

Terms in this set (26)

Species
distinct form of life
Reproductively Isolated
unable to interbreed under normal circumstances to produce fertile offspring
Prezygotic Isolation
occurs when individuals from different populations are unable to mate
Postzygotic Isloation
occurs when individuals from different populations can mate, but the offspring produced have low fitness
morphospecies concept
A species is a group of individuals that are phenotypically distinct from other such groups; different species look different
phylogenetic species concept
A species is the smallest cluster of individuals that are diagnosably distinct from other such clusters within which there is a pattern of ancestry and descent
Biological Concept
individuals that can mate and produce a fertile offspring are of the same species
Subspecies
Populations that have their own identifying traits but are not distinct enough to be considered a separate species
Speciation
Formation of new species
Allopatry
populations that live in different areas
Allopatric Speciation
The formation of new species in populations that are geographically isolated from one another.
Biogeography
can tell us how colonization and range-splitting events occur
Colonization Isolate Population
often cause speciation because the physical separation reduces gene flow and colonists are likely to experience genetic drift
Vicariance Isolates Populations
Division of a species' range by an extrinsic barrier;
Extinction of intervening populations
Continental Drift
the gradual movement of the continents across the earth's surface through geological time.
Theory of Plate Tectonics
The theory that pieces of Earth's outer layer are in constant motion
Sympatry
Populations or species that live in the same geographic region (close enough to mate)
sympatric speciation
results from development of a barrier to gene flow in a population without spatial separation or physical barriers
Polyploidy
condition in which an organism has extra sets of chromosomes
Autopolyploidy
individuals are produced by a doubling of the chromosomes number
allopolyploidy
individuals are produced by hybridization between two different species
Reinforcement
Selection for traits that isolate populations reproductively
Hybrid Zone
A geographic area where interbreeding between the two populations is common and there are lots of hybrid offspring
Symbiosis
occurs when individuals of two different species live in physical contact
Endosymbiosis
occurs when an organism of one species lives inside an organism of another species
Endosymbiosis Theory
proposes that mitochondria originated when a bacterial cell took up residence inside a eukaryote about 2 billion years ago
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