Review Topics. Flashcards
process whereby organisms better adapted to their environment tend to survive and produce more offspring
natural selection
process by which organisms change over time as a result of changes in heritable or behavioral traits
evolution theory
trait with a current functional role in the life of an organism that is maintained and evolved by means of natural selection
adaptation
groups of individuals belonging to the same species that live in the same region at the same time
population
the set of all genes or genetic information in any population usually of a particular species
gene pool
features that often have different functions but are structurally similar because of common ancestry
homology/homologous structures
the breeding of plants and animals to produce desireable traits
artificial selection
based on variation in alleles of the genes in a gene pool. Occurs both within and among populations, supported by individual carriers of the variant genes
gene variation
a permanent, heritable change in the nucleotide sequence in a gene or a chromosome, the process in which such a change occurs in a gene or in a chromosome
mutation
allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences
hardy-weinberg principle
chance events can cause allele frequencies to flucutate unpredictably from one generation to the next
genetic drift
catastrophies leaving a small surviving population unlikely to have the same genetic makeup as the original, leaving small population
bottleneck effect
genetic drift is likely when a few individuals colonize an island or other new habitat this is what is produced
founder effect
a population may gain or lose alleles when fertile individuals move into or out of population when gametes are transferred between populations
gene flow
the contribution of an individual makes to the gene pool of the next generation relative to the contributions of the other individuals
relative fitness
stabilizing selection
favors intermediate phenotypes
directional selection
shifts overall makeup of the population by acting against individuals at one of the phenotypic extremes
disruptive stabilization
typically occurs when environmental conditions vary in a way that favors individuals at both ends of a phenotypic range over individuals with intermediate phenotypes
form of natural selection in which individuals with certain traits are more likely than other individuals to obtain mates
sexual selection
occurs when natural selection maintains stable frequencies of two or more phenotypic forms in a population
balancing selection
type of balancing selection which heterozygous individuals have greater reproductive sucesses than either type of homozygote, with the result that two or more alleles for a gene are maintained in the population
heterozygote advantage
frequency dependent selection
type of balancing selection maintains two different phenotypic forms in a population
the process by which one species splits into two or more
speciation
define a species as a group of populations whose members have the potential to interbreed in nature and produce fertile offspring
biological species concept
prevents genetic exchange and maintains a boundary between species
reproductive isolation
pairs of distinct species that occasionally interbreed
hybrids
most organisms classification is based mainly on physical traits such as shape, size and other features of morphology
morphological species concept
identifies species in terms of their ecological niches focusing on unique adaptations to particular roles in a biological community
ecological species concept
defines a species as the smallest group of individuals that share a common ancestor and thus form one branch on the tree
phylogenetic species concept
prevent mating or fertilization between species
prezygotic barriers
operates after hybrid zygotes have formed
postzygotic barriers
the initial block to gene flow that may come from a geographic barrier that isolates a population
allopatric speciation
a new species arises within the same geographic area as its parent species
sympatric speciation
evolution of many diverse species from a common ancestor
adaptive radiation
describe long periods of little apparent morphological change interrupted by relatively brief periods of sudden change
punctuated equilibria
developed on the sequence and ages of rocks and fossils
geologic record
the end of an organism or a group of organisms, normally a species, the moment is generally considered the death of last individual
extinction
rapid and disruptive environmental change that a majority of the species were swept away in a relatively short period of time
mass extinction
mutation,migration, genetic drift and natural selection
mechanisms of macroevolution
studying how slight genetic changes become magnified into major morphological differences between species
evo devo
the evolutionary history of a species or group of species
phylogeny
a discipline of biology that focuses on classifying the organisms and determining their evolutionary relationships
systematics
use of molecular genetics to study the evolution of relationships among individuals and species
molecular systematics
taxonomic rank
class
group of closely related species
genus
species from a lineage that is known to have diverged before the lineage that inclueds the species we are studying
outgroup
the adoption of the simplest explaination for observed phenomena
parsimony
a method that estimates the time required for a given amount of evolutionary change
molecular clock
a group of individuals of a single species that occupy the same general area
population
concerned with changes in a population size and the factors that regulate populations over time
population ecology
number of individuals of a species per unit area or volume
population density
clumped dispersion pattern
individuals grouped into patches, most common in nature
uniform dispersion pattern
even dispersion, form from interactions between individuals of a population
random dispersion
individuals in a population are spaced in a unpredictable way without a pattern
plot survivorship as the proportion of individuals from an initial population that are alive at each age
survivorship curve
