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Speciation and Conservation - Coggle Diagram
Speciation and Conservation
Translocation may lead to reproductive outcomes that are...
Beneficial, if new individuals are from the same species
decreased likliehood of inbreeding and offspring inheriting undesirable alleles and traits
new individuals may introduce alleles and traits to the population that are advantageuos
Costly, if new individuals are actually from a different species
they may not be able to produce fertile offspring
offspring they produce would be hybrids that are different from the species conservationists are trying to save
The speciation process:
separation of a single ancestral population into two or more isolated populations
roles of the mechanisms of change in creating fixed differences among each isolated population include:
Absence of gene flow
Presence of:
mutation
genetic drift
natural selection
steps:
Similar Isolated Populations
Mechanisms of change lead to an accumulation off genetic and phenotypic differences.
One Species
Something causes a population to separate.
Different Isolated Populations
Genetic and phenotypic differences reach a point where the populations may be considered separate species.
Different species?
Natural selection may favor different variations in traits between populations that:
already existed when they separated
newly arose from chance mutations
How do we define a species?
Morphological Species Concept
defines two populations that have distinguishible phenotypic characteristics as two different species
Limitations:
does not take modern genetics into account
less accurate than using ecological and molecular evidence
oldest species concept
Biological Species Concept
defines a species as members of populations that actually or potentially interbreed in nature and produce offspring that are fertile
Limitations:
assumes sexual reproduction, and therefore cannot be used for asexually reproducing species
We cannot test the ability to mate between every pair of species -- impractical and unethical
Phylogenetic species concept
defines species as groups of individuals that share a unique common ancestor
species are identified by estimating the phylogeny of closely related populations and finding the smallest monophyletic groups
Asexually Reproducing Species: Bacteria and Archaea
gene flow in these species occurs in the absence of reproduction
results in genetic recombination
new combinations of alleles
Best defined in an ecological context
according to Lawrence and Ochman: gaining novel alleles by lateral transfer is the primary mechanism of speciation in bacteria
Hybridization and Gene Flow between species
Even when two populations are considered separate species, there may be gene flow between them
secondary contact: interbreeding between the two sister species