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BIO 320 Final #umobile
Covers lecture notes from Chapters 5 and 8. Bio 320, University of Mobile
72
Biology
Undergraduate 3
05/04/2013

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Term
2 Conditions of Natural Selection
Definition
Variation occurs among individuals

Variations result in differences
Term
Fitness
Definition
Measured by the proportional contribution to a future generation
under a given set of environmental conditions, individual traits are selected for or against
Term
Evolution
Definition
the change in the properties of population (species) over the course of generations
Term
The Origin of Species
Definition
Darwin presents the theory of natural selection designed to enable them to survive and reproduce (fit over unfit)
Term
Adaptation
Definition
genetically determined characteristic that improves an organisms ability to survive and reproduce under prevailing environmental conditions
Term
Genes
Definition
unit of inheritance
Term
phenotype
Definition
observable expression
Term
phenotypic variation
Definition
occurs because most traits have more than one gene affecting them
Term
most traits are affected by
Definition
the environment
Term
species are usually composed of
Definition
interbreeding subpopulations linked by movement of individuals
Term
gene pool
Definition
the total genetic variation of alleles within a population
Term
allele frequency
Definition
the most common measure of genetic variation (genotype frequency)
Term
Phenotypic evolution
Definition
a change in the mean or variance of a phenotypic trait across generations due to changes in allele frequencies
Term
natural selection acts on the phenotype by
Definition
altering both genotype and allele frequencies within a population
Term
3 general types of natural selection
Definition
directional selection
stabilizing section
disruption
Term
directional selection
Definition
favors individuals at one extreme of phenotype
Term
stabilizing selection
Definition
favors middle
Term
disruption
Definition
favors 2 extremes of phenotypes in a population which have greater fitness that the intermediate
Term
target of selection
Definition
the phenotypic trait that natural selection acts upon
Term
selective agent
Definition
the environmental cause of fitness differences among individuals in a population
Term
do all phenotypic traits represent adaptations?
Definition
no
Term
mutations
Definition
heritable traits in a gene or chromosome
Term
migration (as related to genes)
Definition
results in transfer of genes between local populations (gene flow)
Term
genetic drift
Definition
change in allele frequencies due to random chance
Term
each generation represents
Definition
a subset or sample of the previous generations gene pool
Term
Hardy-Weinberg principal
Definition
genotypic ratios remain unchanged generation to generation provided that 1)natural selection doesn't occur 2) genetic drift is insignificant 3) mutations are absent 4) mating is random
Term
Hardy-Weinberg principal functions as
Definition
a null model; deviations give inside into evolutionary forces
Term
Assortative mating
Definition
individuals choose mates non randomly with respect to genotype; mates selected based on some phenotypic trait
Term
positive assortative mating
Definition
males are more phenotypically similar to each other than expected by chance
does not change frequency of individual alleles, but increases proportion of homogeneous individuals
Term
negative assortative mating
Definition
mates are less phenotypically similar to each other than expected by chance
results in an increase of the frequency of the heterozygous individuals
Term
inbreeding
Definition
nonrandom mating of individuals that are more closely related that expected by random chance
Term
inbreeding can by detrimental by:
Definition
offspring more likely to inherit rare, recessive deleteroius genes.
Term
inbreeding depression
Definition
effects of inbreeding
Term
species with broad geographic distribution often experience
Definition
a broad range of environmental conditions
Term
the greater the distance between populations
Definition
the greater the differences
Term
cline
Definition
measurable gradual change in a geographic region in the averages of some phenotype
Term
ecotype
Definition
populations that shoe adaptive responses to breaks along a cline
Term
Example: Yarrow Ecotypes
Definition
differences in hight based on environment of local populations
Term
Geographic isolation
Definition
free slow of genes among subpopulations is prevented in great part by some sort of barrier
Term
Geographically isolated subpopulations become
Definition
subspecies
Term
adaptive radiation
Definition
evolution from a common ancestor; often rapid
Term
fitness of any phenotype is a function of the
Definition
prevailing environment
Term
characteristics that enable an individual to maximize fines under one set of conditions
Definition
generally limits its ability to do so under a different set of conditions
Term
phenotypic plasticity
Definition
ability of a genotype to give rise to a range of phenotypic expression under different environmental conditions
Term
norm of reaction
Definition
Range of phenotypes produced by a particular genotype in different environmental conditions.
Term
developmental plasticity
Definition
occurs during growth and development of an individual and represents an irreversible characteristic
Term
example of developmental plasticity
Definition
small size and slow metabolism can facilitate survival in adverse conditions
Term
acclimation
Definition
reversible phenotypic changes in an individual organism in response to environmental changes
Term
Most important property of population
Definition
abundance
Term
abundance
Definition
determined by distribution and density
Term
distribution
Definition
spatial location, area over which a species occupies
Term
geographic range
Definition
area that encompasses the entire population of species
Term
direct climatic limitation
Definition
temperature, precipitation
Term
indirect climatic limitation
Definition
food production, water supply, habitat, parasites/competitors, geographic barriers
Term
Example: Climate limitation
Definition
Red maples limited to north by temp; carolina wrens limited to the east by moisture
Term
Abundance equation
Definition
Abundance=(distribution area)(population density)
Term
3 distribution patters
Definition
1)Random
2)Uniform
3)Clumped
Term
Random Distribution
Definition
caused by natural interactions between individuals in a local environment.
Only occurs in uniform habitats, and is therefore rare
Term
Regular distribution
Definition
species evenly spaced; antagonistic intraspecific competition
Term
Clumped distribution
Definition
generated by habitat differences; most common type
Term
age structures
Definition
the number of proportion of individuals in different age groups
Term
Why is age distribution often skewed in plant populations?
Definition
older trees outcompete newer organisms
Term
Sex Ratios
Definition
populations of sexually reproducing organisms tend toward a 1:1 ratio
Term
Human sex ratios
Definition
more males at birth
males have shorted lifespans, partially due to activities requiring increased risk
females need to survive childbirth
Term
dispersal
Definition
movements of individuals in space
Term
passive dispersal
Definition
gravity, wind/water, animal, seeds of plants, small animals, fish, shrimp
Term
active dispersal
Definition
animal movement
Term
emigration
Definition
individual moves out of a subpopulation
Term
immigration
Definition
individual moves from another area to a new one
Term
migration
Definition
a round trip, perhaps involving mating
Term
Population density
Definition
number of individuals per unit area
Term
ecological density
Definition
the habitat space actually inhabited or utilized by a species
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