Processes of evolution
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What is a species?
the generation of a reproductively isolated po
What is the biological species concept
States that species is interbreeding group that makes fertile offspring
Identify and explain the four main mechanisms leading to evolution?
nat selection – inc allele freq, produces adaptaton, , genetic drift – random fluctuation in allele freq, Random in selection and population size , gene flow, - opposite of genetic drift , Reduces genetic diversity between pop. Makes pops more similar to each other Mutation – introduces new alleles, uusually not successful.
Why is artificial selection natural selection? Why might we consider it different
This could be natural selection because we are a species, homo sapiens and it is the pressure we induce on another species that causes it to change. It might be considered something different because we do it intentionally.
Why is genetic drift an important issue concerning the conservation of species? give ex
A bottle neck causes one allele to disappear entirely, in a small population with low diversity this could be bad. Low diversity means possibility of interbreeding and also one sickness could wipe them all out.
What are the 3 mechs of speciation
Allopatry - geological Parapatry - theres a hybrid zone, hybrids become their own species, slow Sympatry - symbiotic animals change hosts and stay on hosts.
Identify two mechanisms for speciation and explain their links to evolution.
Allopatry parapatry Sympatry The animals can no longer interact for whatever reason. causes them to evolve independantly and make a new species
what is genotype
complete set of genes in an organism genetic info inherited from parents
What is phenotype
set of observable chars on an org. determined by the genotype and env
Why is hardy weinberge princple a null hypothesis what is it, eq, what does it do
p^2 +2pq +q^2 = 1 how to know if evolution is happening or not Analyze the allele freq before and after random mating Randomly combines all gamates Predicts genotypes and freq of genotype The hardy weinberg should be proven false always because evolution should be happening
What are the fundamental claims of the hardy weinberg principel
If A = p and a = q then the freq of the genotypes Aa, AA and aa will equal p^2, 2pq, q^2 for every gen Frequencies of alleles do not change over time
what 5 conditions are met for hardy weinberg to work
1) no natural selection (2) no genetic drift (3) no gene flow (4) no mutation (5) random mating
Use terms allel, dominant, recessive to differentiate homo and heterozygous genotype
Dominent is A recessive is a Homo is AA or aa Hetero is Aa
What is a prezygotic barrier? types 5
Stops zygote from forming geo - diff places temperal - diff times behavioral - diff ways of mating, dancing morphological - not fitting genetic - sperm wont work on egg
What is a postzygotic barrier, types
Hybrid depression - hybrids not as well liked among either types ex mallards and black duck hybrid - hybrids die before maturity -hybrids sterile ex mules
What are the types of natural seleciotn
Directional - inc allele frq in one direction, reduce diversity divergent - selects against intermediate, reduces genetic difersity into 2 directions sexual - when the selective force is for mating, those with better fitness. Sometimes reduces diversity artificial selection? - reduce diversity, done by humans