by Raychelremmert
Last updated 5 years ago


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Natural selection is organisms better adapted to their environment tend to survive and produce more offspring. Charles Darwin created this theory.

In many species, there have been catastrophic periods caused by changes in natural selection, during which most have died without passing on their genes. The few survivors of these evolutionary "bottlenecks" then were reproductively very successful, resulting in large populations in short generations.Therefore the bottleneck effect is the reduction in genetic diversity of a species since most variability is lost at the time of the bottleneck.

Gene flow is the transfer of alleles or genes from one population to another.


Allopatric speciation is something extrinsic to the organisms prevents two or more groups from mating with each other regularly, eventually causing that lineage to speciate. Sympatric speciation is the process through which new species evolve from a single ancestral species while inhabiting the same geographic region.

Behavioral isolation are species-specific signals & elaborate behaviors to attract mates.Temporal isolation is an evolutionary mechanism that keeps individuals of different species from interbreeding, even if they live in the same environment. Geographic isolation is the separation of two populations of the same species or breeding group by a physical barrier, such as a mountain or body of water.

A gene pool is the stock of different genes in an interbreeding population.

Genetic Drift is the variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.

Genetic drift can cause big losses of genetic variation for small populations. Population bottlenecks occur when a population's size is reduced for at least one generation

Bottleneck effect: Drastic short-term reductions in population size caused by natural disasters, disease, or predators; can lead to random changes in the population's gene pool.

A mutation is the changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.

Non Random Mating: individuals with similar genotypes and/or phenotypes mate with one another more frequently than would be expected under a random mating pattern.

A hybrid is mix of two animals or plants of different breeds, varieties, species or genera.


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