Mechanism of Evolution Flashcards
all living organisms have a common ancestor, but because of millions of years of evolution, each of the organisms became what they are today
theory of evolution
acts to encourage traits and behaviors that increase the likelihood of an organism’s CHANCE FOR SURVIVAL and reproduction while eradicating those traits and behaviors that are disadvantageous to the organisms
natural selection
that nature (the environment) selects individuals which use resources most efficiently
natural selection
fuel the process of evolution by PROVIDING NEW GENES in the gene pool of a species
mutations
refers to MUCH BIGGER EVOLUTIONARY CHANGES that result in new species
macroevolution
agents of revolutionary change
genetic drift
gene flow
mutations
nonrandom mating
artificial selection
recombination
changes in allele frequencies due to CHANCE ALONE
genetic drift
when a few individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool differs from the source population
founder effect
happens when some catastrophe , like an earthquake or tsunami, kills off most of a population at random and leaves only a handful of survivors
bottleneck effect
TRANSFER of alleles INTO OR OUT OF A POPULATION due to the movement of fertile individuals or their gametes
gene flow
introduces new genetic variation to populations in different geological locations and habitats
gene flow
CHANGES in an organism’s DNA, driving diversity in populations and contributing to evolution
mutation
random; they cannot decide
mutations
atl some individuals are MORE OR LESS LIKELY TO MATE WITH INDIVIDUALS OF A PARTICULAR GENOTYPE THAN WITH INDIVIDUALS OF OTHER GENOTYPES
nonrandom mating
preference for similar genotypes/phenotypes
assortative mating
preference for different genotypes/phenotypes
disassortative mating
this mechanism is due to human intervention
artificial selection
humans select which phenotypes of organisms will be beneficial
artificial selection
genetic diversity can also arise from _____ of the DNA from 2 diff cells via ___, ____, ____
recombination; transformation, transduction, conjugation
by transferring advantageous alleles, such as one for ____ ____, genetic recombination can promote adaptive evolution in prokaryotic populations
recombination; antibiotic resistance
provides a framework for understanding how populations evolve
hardy-weinberg equilibrium
describes populations that are not evolving
hardy-weinberg equilibrium
conditions for hardy-weinberg equilibrium
no mutations
random mating
no natural selection
extremely large population size
no gene flow
gene pool is modified if mutations occur or if entire genes are duplicated or deleted
no mutations
if individuals mate within a subset of the population, such as near neighbors or close relatives (___), random mixing of gametes does not occur and genotype frequencies change
random mating; inbreeding
allele frequencies change when individuals with different genotypes show consistent differences in their survival or reproductive success
no natural selection
in small populations, allele frequencies fluctuate by change over time (___)
extremely large population size; genetic drift
by moving alleles into or out of populations, __ __ can alter allele frequences
gene flow
Population in which allelic frequency does NOT change over generations
genetic equilibrium
population is NOT evolving
genetic equilibrium
He didn’t know how heredity worked
darwin’s handicap
2 gaps in darwin’s thinking
didn’t know how traits were inherited
variation in heritable traits was central to his theory, but he had no idea how that variation appeared
2 main sources of genetic variation
mutations
gene shuffling
caused by mistakes during replication or environmental factors such as radiation or chemicals
mutations
source of new phenotypes
mutation
mixing of genes during the production of gametes in meiosis
gene shuffling
the exchange of genetic material during prophase I
crossing over
change in a population’s allele frequencies over short time periods
microevolution
branch of biology that studies the genetic variation within populations and how this variation changes over time and geographical space
population genetics
provides insights into microevolutionary processes such as mutation, selection, gene flow, and genetic drift.
population genetics
entire collection of all the alleles in a population
gene pool
number of times an allele appears in the gene pool
allelic frequency
can only select or choose traits that are favorable and cannot create new ones
natural selection
key mechanism of evolution that leads to speciation
natural selection
change in allele frequencies in a population
evolution
