Chapter 17: Population Genetics & Evolution

Population Genetics

deals with the abundance of different alleles within a population

factors that cause genes to change

mutation

existing alleles decrease in frequency

new alleles increase in frequency

accidents

events to which an organism can't adapt

artificial selection

humans purposefully change the allele frequency of a gene pool

natural selection

most significant factor

survival of the fittest

factors that are part of natural selection

purpose

intention

planning

voluntary decision making

Speciation

natural selection as causes a new species to evolve

two ways

phyletic speciation

one species gradually becomes changed to where it becomes a new species completely

divergent speciation

some populations of species evolve into a new, second species

gene flow

movement of alleles physically through space

pollen transfer

pollen grains each carry one full haploid genome

seed dispersal

some fall close to the parent

many have long distance dispersal

vegetation propagation

species produces a small, mobile piece that reproduce vegetatively

abiological reproductive barriers

physical nonliving feature that prevents two populations from exchanging genes

biological reproductive barriers

any biological phenomenon that prevents successful gene flow

adaptive radiation

species rapidly diverges into many new species over a very short time

convergent evolution

when two unrelated spiced occupy the same or similar habitats

natural selection may favor the same phenotypes in each

the two may evolve to a point where they resemble each other a lot

Evolution and the Origin of Life

chemosynthesis

model the origin of life using only known chemical and physical processes

rejecting all traces of divine intervention

conditions on earth before the origin of life

chemicals present in the atmosphere

mostly hydrogen

second atmosphere

hydrogen sulfide

ammonia

methane

water

energy sources

UV and gamma rays from the sun

time available for the origin of life

no limits

artificial selection

speciation