Biology Keyworks

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/chromosome for diploid organisms

-genetic variations in alleles can result in differences, also can be unnoticeable

 Allele frequencies: the abundance of one allele relative to others at the same gene locus in individuals of a population to describe genetic diversity

-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

- Populations evolve independently and diverge into different species

-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)

 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... [continues]

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