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Speciation:- Species : _____________________________________________________________________________________________________________________________o Diversity arises w/in a species stays in the specieso Each is unique and distincto This is also true of individuals or pops. Species are distinct in an evolutionary sense.- Speciation : when pops become genetically/reproductively isolated for lack of gene flowo Can occur with or without natural selection.o The divergence is strengthened by___________________, ____________________, ____________________.o If a single population is split into two populations that are unable to interbreed, different mutations will appear by chance in the two populations.o Two separate populations will gradually become distinct as different mutations are introduced and propagated in each population. At some point, they will become incompatible. o Partially Reproductively Isolated : ___________________________________________________________________________________ Hybrid offspring may have reduced fertility or viability.o Allopatric Speciation : ___________________________________________________________________________________________________ May form ______________________________. Dispersal : _______________________________________________________________________________________________________ Vicariance: ______________________________________________________________________________________________________ Peripatric Speciation : _____________________________________________________________________________________________________________________________________________________________________________________________________________- Mainland Population : the central population of a species.- Island Population : geographically remote from the initial mainland population’s habitat.o Classically small ad often in an environment that’s slightly different from that of the mainland population.o Genetic Drift is more pronounced in small populations.o Adaptive Radiation : ______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Occurs when there are many ecological opportunities available for exploitation.o Co-speciation : ____________________________________________________________________________________________________________o Sympatric Speciation : __________________________________________________________________________________________________Difficult to find evidence of it.o Instantaneous Speciation : ___________________________________________________________________________________________________________________________________________________________________________________________________________________________Chromosome # may change in hybridization.-Tetraploid : hybrid inherits a _________________________________ of chromosomes (2 from each) from each parental species.o Some organisms cannot sustain this.-Polyploid : inherits ___________________ chromosome sets.o Reinforcement of Reproductive Isolation : the process by which diverging populations undergo natural selection in favor of enhanced prezygotic isolation to prevent the production of less fit hybrid offspring.Mating Discrimination- Biological Species Concept (BSC): o Species are groups of interbreeding populations that are reproductively isolated from other species. Different species _________________ breed with each other.o Problems: You would need to test whether organisms can reproduce in order to categorize them as a species. Organisms of the same species might not reproduce.o Doesn’t apply to asexual or extinct organisms.- Morphological Concept: o Members of the same species usually look ________________________. Problems:- Some species look alike.- Males may look different than females.- Members of a single species may not look alike.- Ring Species: ______________________________________________________________________________________________________________________ ______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________- Hybridization: ________________________________________________________________________________________________o Mainly in plants.- Ecological Niche: o A complete description of the role the species plays in its environment.o Nutritional needs, water, habitat, etc.o It is impossible for two species to coexist in the same location if their niches are ___________________ because ___________________ between them for resources will lead to the extinction of them.- Ecological Species Concept (ESC): there is a one-to-one correspondence between a species and its niche- Evolutionary Species Concept (EvSC): the idea that members of a species all share a common ancestry and a common fateo Requires that all members of a species are descended from a __________________________________.- Reproductive Isolation: o Prezygotic Isolation: ___________________________________________________________________________________ Incompatibility between sperm and egg. Physical features. Lock and Key: both components (physical or biochemical) must ____________________ for successful interaction. Temporal Separation : isolated in time Ecological Separation : isolated by space Behaviorally Isolated : ________________________________________________________________________________________________________________________________________________________________________o Post-zygotic Isolation: _________________________________________________________________________________ Typically involve some kind of ___________________________________________. Zygote must fail to develop after fertilization. May produce viable but ________________________ offspring.- Species Concepts: different ways to define a specieso Phylogenic Species: _____________________________________________________________________________________ Tree of Life: shows how every species is connected Recognizes more species than other

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UConn BIOL 1108 - Species

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