Process that helps an organism survive and reproduce in a particular environment
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Structural adaptation
Adaptation that changes the structures in an organism (opposable thumb)
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Behavioural adaptation
Change in behaviour that helps organism survive (hibernation)
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Physiological adaption
Change in the organisms ability to regulate and maintain homeostasis (venom)
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Mimicry
Many harmless organisms ressemble harmful organisms in colouration or structure... avoid predators (Massasauga Rattler - venomous; Fox snake - non venomous)
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Natural selection
The process of populations changing in favour of those who have advantangeous traits due to environmental pressures. - Occurs only in populations with variation
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Fitness
Measured by the # of fertile offspring produced in the next generation
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Artificial selection
Describes changes to a population caused by deliberate, selective breeding by humans
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Microevolution
Change in allele frequencies in a population over generations
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Point mutation
Change in one base in a gene
- Mutations in noncoding regions of DNA are often harmless - Mutations might not affect protein production because of redundancy in genome
- Mutations that change protein production are often harmful - Can sometimes increase the fit between organism and environment
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Population
Localized group of individuals capable of interbreeding and producing fertile offspring
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Gene pool
Consists of all the alleles for loci in a population
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Mutation
Change that occurs in DNA of individual, a heritable mutation (in gamete) mutation has the potential to affect an entire gene pool
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Gene flow
Is the transfer of alleles from one population to another, migrations into or out of a population can change allele frequencies.
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Non-random mating
Occurs when individuals select mates based on their phenotypes; interbreeding increases proportion of homozygous dominant and resessive individuals/decrease heterozygous
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Genetic Drift
Refers to changes in the allele frequencies of a gene pool due to c hance events
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Founder effect
Occurs when a few individuals found a colony. Only a small fraction of the total genetic diversity of the original population is represented.
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Bottleneck effect
Loss of genetic diversity due to extreme reduction in size of a population (extinction). Prevents majority of genotypes from participating in the production of the next generation; alleles of survivors dictated by chance - Rare alleles are likely to be eliminated
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Natural selection
Result of environment selecting for individuals in a population with certain traits that make them better suited to survive and reproduce than others
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Stabilizing selection
Average phenotype within a population is favoured by the environment.
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Directional selection
favours individuals with a more extreme variation of a trait causing a shift away from average conditions.
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Disruptive selection
Favours individuals with variations at opposite extremes.
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Vestigial features
structures that once performed an important function in ancestral species that now have no use (i.e. tailbone, appendix, wisdom teeth, pig’s hind toe etc.)
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Biogeography
Remote islands are populated by species that evolved from species that had travelled from closest major land mass
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Homologous structures
share similar physical features, but may not serve the same purpose. indicates CLOSE ANCESTRY.
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Analogous structures
may share a common function, but do not have similar anatomy, therefore DO NOT INDICATE CLOSE ANCESTRY.
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Competition within populations
All species have more offspring than can survive to reproduce
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Species
a group of similar organisms which can interbreed and produce fertile offsprings
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Sexual selection
Any trait that aids in an organisms ability to attract mates and breed