Unit 2:Organisms and evolution KA2.2-evolution Flashcards
define the term evolution
evolution is the change over time of the proportion of individuals in a population differing in one or more traits
what can cause evolution to be rapid
selection pressures
name the 2 types of selection pressures
biotic and abiotic
name some biotic factors
competition, predation, parasitism and disease
name some abiotic features
changes in temperature, light, humidity, pH and salinity
what are the 2 types of evolution
random and non-random
example of random evolution
genetic drift, examples of this is population bottleneck and the founder effect
types of non random selection
natural selection and sexual selection
why does variation exist in a species
mutations
description of male-male rivalry
large size or weaponry increases access to females through conflict
description of female voice
female choice involves females assessing the fitness of males
define genetic drift
the ratio of genotype change randomly overtime and can result in some alleles being under or over represented
describe population bottleneck
a population bottleneck is an event that drastically reduced the size of a population for at least one generation, leaving a population with a reduced genetic diversity
describe the founder effect
founder effect occurs through the isolation of a few members of a population from a larger population
this new gene pool is not representative of the original one
the 5 conditions for maintaining the hardy-weinberg principle
-no selection occurring
-no mutation
-no migration
-random mating
-large population
