BIO FINALS

• Speciation is the evolution of one or more species from a single ancestor species
• Allopatric Speciation -speciation that occurs in geographically isolated population. Separation is due to different geographical events
• Peripatric Speciation- small subset of a large population becomes isolated at the periphery of the original population's rang

  -Over generations, the small group becomes reproductively isolated from the original population.
• Sympatric Speciation - a species splits into two groups that diversify and become genetically isolated while remaining in the same place.
• Parapatric Speciation- Individuals are more likely to mate with their geographic neighbors. This also results in a reduced gene flow within the population

  -There is no specific barrier to gene flow

  -the mating behavior is NOT random
• Autopolyploidy -chromosomes in the new species are all from the same ancestral species
• Allopolyploidy - chromosomes in the new species come from two different but related ancestral species
• Hardy-Weinberg Principle -also known as the Hardy-Weinberg equilibrium, model, theorem, or law, states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.
• Population - a group of individuals where mates are usually found.
• Gene pool - all the alleles in a populatio
• Species  a group of organisms whose members are capable of interbreeding under natural circumstances to reproduce fertile (viable) offspring
• Mutation - change in DNA structure
• Segregation  - the separation of homologous chromosomes into different cells at cell division.
• Independent Assortment - what occurs when genes on different chromosomes segregate to gametes independently of one another.
• Recombination -  the exchange of genetic material between pairs of chromosomes during the first stage of meiosis.
• Natural Selection  - the environmental selection of species that influence differential reproductive success
• Gene Flow - the process in which alleles from one population are introduced into another population
• Genetic Drift - Random changes in a small population that are the products of chance
• Directional Selection- Selection characterized by a generation-after-generation shift in a population in a specific direction. One extreme trait is being favored
• Stabilizing Selection- characterized by a generation-after-generation in a population toward a mean (average). Individuals with the average form of  a trait have the highest fitness.
• Disruptive selection - occurs when extreme values for a trait are favored over the intermediate values. This type of selection often drives speciation.
• Intersexual Selection -Traits that make males more attractive to females
• Intrasexual Competition- Sexual selection that makes males better able to compete for sexual access to females
• Sexual Dimorphism - or the physical difference of males and females of the same species, plays a role in both species
• Gene flow - exchange of genes among populations through interbreeding
• Breeding populations - populations within a species that to some extent are genetically isolated from other species
• Demes - same definition as breeding populations with emphasis on smallest of such populations
• Non-random mating – individuals prefer mates with particular superior physical characteristics or by the preference of individuals to mate with individuals similar to themselves.
• Consanguineal Mating- Mating between biological relatives
• Incest Tabu – The prohibition against mating with close relatives, especially primary relatives (father-daughter, mother-son, and brother-sister
• Cross-Cousin Marriage – A practice often observed, even required, between offspring of brother and sister. Gene flow is limited here
• Fission- Splitting up of population to form new populations (taking place usually when populations are small)
• Founder Effect - Genetic differences between populations are produced by the fact that genetically different individuals established (founded) the population