Natural Selection/EvolutionAn organisms gene/genomes impact their chances for survival.KEY TERMS:Adaptations – inherited traits that help an individual survive and reproduce in their habitatEvolution – change in allele frequencies OVER TIMEPopulation – all organisms in one area over a time frameAllele – an alternative form of a geneGene – sequence of DNA codes for a specific protein or RNAGenotype – genetic makeup of one individual/what alleles they havePhenotype- individual’s observed properties that can be affected by the environmentCauses of Evolution- Natural selectiono Varied populationso Variation is heritableo Variation effects survival NOT RANDOM, NOT ONLY INDIVIDUALS – MUST BE A WHOLE GROUP OVER TIME- Genetic drifto Founder effect: small, new populations started from larger populations moving, the new population will have slightly different traits and the variation of the new population will be reducedo Bottleneck: size is reduced for one generation which leads to reduced variation in future generations- Mutationo Changes in DNA replicationo Fails to be copied accuratelyo Chemicals/radiation ‘breaks’ the DNAo Can be accumulated over a life but must be inherited to play a rollo This is random- Migrationo Gene flow from certain areasMISCONCEPTIONS- Individuals don’t evolve – evolution happens to a group overtime- Not for the ‘good of the species’ o Cheetahs with long legs survive BECAUSE they can catch more food, then they reproduce and pass down the long leg trait and survive. They don’t change to survive, those that are different and well adapted survive- Response to a current environment and doesn’t anticipate the future- Mutations are random, natural selection is notHardy Weinburg Equilibrium – I don’t think this is super important- No mutations- Individuals mate randomly- No migration- No natural selection- “ideal situation of allele transfer”- I think this situation allows for the same allele to continue foreevverrrMORE KEY TERMSNatural selection – variation of populationSpecies – population whose members can breed and produce offspringSpeciation – process in which new species can form- Doesn’t apply to asexually reproducing organisms (bacteria, arhaea, protists, fungi)- Doesn’t apply to fosil organisms- Organisms have the potential to breed in captivity but not in nature i.e. they get boredAllotropic speciation – new population founded EX: iguanas float to an island after a storm and over time adapt, after generations they are a new version of that iguana type, populations are separated and they evolve/adapt, are then reunited and can mate but also might not be able to.Why does one species avoid mating with another? They don’t want less well-adapted offspring or infertilityNiche – species way of life, habitat, resource use, interactions with other speciesFitness – who passes on the most genes that survive and are able to
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