Chapter 17 Flashcards
Population
Individuals of the same species in the same area
Gene pool
All genes found in one population
Alleles
Different forms of the same gene
Dimorphism
2 different forms of the same species
Poly morphism
The existence of 2 or more forms of individuals within the same animal species
Mutations
Are the source of new alleles that give rise to differences in details of shared traits
Lethal mutations
Usually result in death
Neutral mutations
Have no effect on survival or reproduction
Beneficial mutations
Coney an advantage
Allele frequencies
Relative abundance of alleles in a given gene in a population
Genetic equilibrium
A theoretical state which occurs when a population is not evolving
Micro evolution
Small scale changes in a populations allele frequencies
4 types of micro evolution
Mutations
Natural selection
Genetic drift
Gene flow
Stabilizing selection
Natural selection that favors an intermediate phenotype and elmininates extreme forms
Disruptive selection
Natural selection that favors extreme forms of a trait and eliminates the intermediate form
Sexual selection
Some version of a trait that gives an individual an advantage over others in attracting mates
Sexual dimorphism
Distinct male and female phenotypes
Balanced polymorphism
A state in which natural selection maintains 2 or more alleles at relatively high frequencies
Genetic drift
A random change in allele frequencies over time
Fixation
Has occurred when all individuals in a population are homozygous for one alleles
Bottleneck
A drastic reduction in population size brought about severe pressure like massive disease
Founder effect
Genetic drift is pronounced when a few individuals start a new population
Inbreeding
Breeding or mating between close relatives who share a large number of alleles
Gene flow
Physical movement of allele caused by individuals moving into and away from populations
Speciation
Evolutionary process by which new species form
Reproductive isolation
The end of gene exchange between populations
Temporal isolation
Genetic isolation due to temporal differences in breeding
Mechanical isolation
Incompatibility in structure of the male and female sex organs
Behavioral isolation
Potential mates meet but choose members of their own species
Ecological isolation
Breeding species separated by place
Gamete incompatibility
The male and female gametes unite but do not form viable offspring
Allopatric speciation
A physical barrier arises and ends gene flow between populations
Sympatric speciation
New species form within a home range of an existing species in the absence of a physical barrier
Polyploidy
A change in chromosome number
Parapatric speciation
Populations in contact along a common border evolve into distinct species
Macro evolution
Large scale patterns of evolutionary change
Convolution
2 species in close ecological contact act as agents of selection on each other
Stasis
A lineage exists for millions of years with little or no change
Exaptation
Some complexly traits in modern species held different adaptive value in ancestral lineages
Adaptive radiation
A burst of speciation that occurs when a lineage encounters a new set of niches
Key innovation
A structural or functional adaptation that allows individuals to exploit their habitat in a new way
