MICROEVOLUTION keywords - MICROEVOLUTION Allele – one of...

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Unformatted text preview: MICROEVOLUTION Allele – one of two or more versions of a gene-different alleles can result in different observable phenotypic traits-each trait has 2 alleles-one allele/chrosome for diploid organisms-genetic variations in alleles can result in differences, also can be unnoticeable Allele frequencies: the abundance of one allele relatives to others at the same gene locus in individuals of a population-can be calculated by dividing the number of alleles for a certain trait/the total number of individuals in the population-usually expressed as proportion or a percentage-denoted as “p” or q” Allopatric speciation: a reproductive isolating mechanism that results from geographical separation between two populations-a prezygotic mechanism-caused by glaciers, continental shifts, etc Allopolyploidy: having 2 or more complete sets of chromosomes from different parent species-only plants are capable of this, not animals-results in a fertile hybrid-can be created from previously sterile species (ex bread wheat example) Autopolyploidy: having 2 or more complete sets of chromosomes from the same parent species-again only possible in plants through self fertilization-arise from a failure in the meiotic process-often resemble parents, except grow more slowly and flower later Behavioural Isolation: -a prezygotic isolation process-2 species do not mate because of differences in courtship behaviour-also known as ethological isolation-ex: songs of bullfrogs, fireflies example used in class (sequences of bursts of light vary for different speices of fireflies within males and females) Beneficial mutation: a mutation that proves to be beneficial for the individual; ex increases fitness-can help withstand diseases-ex: those who carry 1 allele of the sickle cell anemia disease are more resistant to malaria in areas of sub-saharan Africa Biological Species: the concept of a species based on the ability of populations to interbreed and produce fertile offspring-basically a reproductively isolated gene pool problems with the concept: how do you define a fossil species? how do you define populations that don’t reproduce asexually? (ex archaea and bacteria) Bottleneck Effect: occurs when an event, such as drought, or over-hunting causes a population to significantly dwindle in size-the survivors reproduce, but there is limited genetic variability-this is a problem! (can be solved by genetic drift) ex: elephant seals example Chromosomal Inversion: a chromosome rearrangement in which a segment of a chromosome is reversed end to end-occurs when a single chromosome undergoes breakage with itself-occurs in the arm of the chromosome, does not involve the centromere-do not usually cause abnormalities as long as the re-arrangement is balanced with no extra genetic info--however increased production of abnormal chromatids result in heterozygous individuals à lowered fertility due to production of unbalanced gametes Chromosomal translocation: rearrangement of parts between nonhomologous...
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This note was uploaded on 12/03/2011 for the course SCIENCE BIO1130 taught by Professor Fenwick during the Spring '11 term at University of Ottawa.

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MICROEVOLUTION keywords - MICROEVOLUTION Allele – one of...

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