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43 Cards in this Set

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  • Back
body parts that were once quite different in evolutionary distant lineages but then cinverged in structure and function because thoes lineages responded similaryly to enviromental pressures
name 3 types of mutations and give an example
a) lethal- heart mutation
b) nuetral- attached or detached ear lobes
c) helpful- bacteria resisting the anitbiotics that can kill them
genetic drift
changes in allele frequencies over the geberations as brough about by change alone
a very slow process that starts when an organism or traces of it become buried in volcanic ash or sedaments at the bottom of some lake lagoon or sea
balanced polymorphism
a type of genetic variation persisrs over time
the layering of sedimentary deposits
natural selection
the outcome in differences in survival and reproduction among individuals that vary in details if heritable trait
allele frequencies
the abundance of each kind of allele in a population
lethal mutation
severe effects on phenotype results in death
neutral mutation
does not help nor harm
sampling error
the fewer time a chance event occurs, the greater will be the variance from the expected outcome of an occurance.
only one kind of allele remains at a particualr locus in the population; all of the individuals are homozygous for it.
genetic flow
microevolutionary process; alleles enter and leave a population as an out come of immigration and emigrations
Natural selection is an microevolutionary process that results in the differntial survival and reproduction of the individuals of a population that differ in one or more traits, state the main points of the theroy
the individuals of population will end up competing for reources
some phenotype are betetr than other sna more adapt to the enviroment than others, Alleles increas the population, genetic change leas ti uncreased fitness over time or an increased adaption.
kinds of genes occur in slightly different forms
geological time scale
boundires between the intervals of a chronological time chart
an increase of adaption to the enviroment
directional selection
mode of a natural selection by which allele freqencies underlying a range of phenotypic variation shift in a consistant direction in response to directional change or to new conditions in the enviroment
how does directional selection apply to peppered moths
light and dark winged moths, have different colors in different enviroments to blend in
how does directional selection apply to pesticide resistance?
pests servive pesticide pass down the trait to future generations
mutation rate
the probability of its mutating in or between DNA replications
how does directional selection apply to antibiotic resistance
as bacteria survives it becomesmore resistant
Allele freqencies change when a population evolves, HArdy weinberg came up with an equation that establishes freqencies at equilibrium. What conditions must exist for this formula to apply
if there is no mutation
is the population is infinitely large
population is isolated from other populations of the same species
if matimg is random regarding the alleles
if all individuals survived reproduce equally
stabilizing section
intermidiate forms of a trait are favaored and alleles that specify extreme forms are eliminated from a population
morphological convergence
lineages thata re remotly related slowly evolve in similar directions
sexual selection
the traits selected are advantageous, with respect to survival and reproduction, simply because males or females perfer them.
disruptive selection
forms at both ends of the range of variation are favored and itermediate forms are selected against
the study of the world distribution of organisms
a similarity of one or more body parts in different organisms that we attribute to the decent of a common ancestor
morphological divergence
the change from a body from of a common ancestor
small scale changes in allele frequencies brought about by gene mutation, natural selection, gene flow, and genetic drift
genetic equlibrium
the frequencies of alleles at a given gene locus remain stable, one generation after another
Individuals dont evolve... explain
populations do, they change and evolve over millions of years in order to help populations to survive.
gene pool
all genotypes in a population
all indviduals of the same species occupying the same area
nonrandom mating along closly related individuals which may have identical alleles in common
Name 5 sources of variation
a) gene mutation
b) crossing over at meiosis 1
c) independent assortment
d) fertilization ( the combination of alleles) from 2 parents
e) change in chromosome number or structure
evidence of a past life
changes in the lines of descent
According to darwin, what might variation in traits do?
variations in tratis might affect and individuals ability to secure resources- and therefore survive and reproduce in praticular enviroments.
Darwins theroy
a population can evolve when individuals differ in one or more heritable traits that are responsible for differences in the ability to survive and reproduce
a gene existing in two or more slightly different molecular forms
qualitative variation, eye color, height ect.
comparative morphology
the systematic study of similarities and differences in the body plans between major groups, such as different kinds of vertebrates