evolution/natural selection/variation Flashcards
FFwhat is evolution
the gradual change in heritable traits of organisms many millions of years (successive/several generations)
what is evolution (as a genetic def)
a change in the allele frequency of a populations gene pool over successive generations
heritable traits are encoded for by … and may be transferred
genes and may be transferred between generations as alleles
darwins obs: organsism produce…
more offspring than survive
darwins obs: theres variation in…
the characteristics of members of the same species
darwins obs: some of these characteristics can be…
passed on from one genration to the next
darwins obs: individuals that are best adapted….
to their environment are more likely to survive
darwins obs: populations do not…
fluctuate significantly
What is the name of the mechanism by which evolution occurs
natural selection
describe the process of natural selecion
a new ALLELE arising from random mutation leads to increased REPRODUCTIVE SUCCESS is inherited by the next generation. Over many generations, the new allele increases in FREQUENCY in the population
principals of NS: over pro…..
over production leads to competition
principals of NS: variation due to
mutaion
principals of NS: selection via
adaption (surival of the fittest)
principals of NS: breed and pass…
on characteristics
what is a selection pressure
a factor which affects an organisms chance of survival or ability to reproduce
what are the 5 density dependent factors/selection presures
predators
availability of resources
nutrient supply
disease (pathogenic spread)
accumulation of wastes
what are the 3 density independent factors/selection pressures
abiotic factors
weather conditions
offspring generally appear similar to their parents deducting that
characteristics are passed on to the next generation