Post on 16-Jul-2015
Adaptive Radiation
adaptive radiation is the evolution of ecological and phenotypic diversity within a rapidly multiplying lineage.
Allometric Growth
the variation in the relative rates of growth of various parts of the body, which helps shape the organism
Allopatric Specification
a mode of speciation induced when an ancestral population becomes segregated by a geographic barrier or is itself divided into two or more geographically isolated subpopulations
Allopolyploid
a common type of polyploidy species resulting from two different species interbreeding and combining their chromosomes
Artificial selection
the selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits
Bottleneck Effect
genetic drift resulting from the reduction of a population such that the surviving population is no longer genetically representative of the original population
Cline
clines consist of ecotypes or forms of species that exhibit gradual phenotypic and/or genetic differences over a geographical area
Convergent Evolution
species evolve to have structures with similar functions due to similar environments
Diversifying Selection
Disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values.
Founder Effect
genetic drift that occurs when a few individuals become isolated from a larger population with the result that the new population's gene pool is not reflective of the original population
Frequency-dependent Selection
a decline in the reproductive success of a morph resulting from the morph's phenotype becoming too common in a population; a cause of balanced polymorphism in populations
Gametic Isolation
If the gametes of two species meet, fertilization may not occur because of gametic isolation, in which the egg and sperm of different species are incompatible.
In coral reefs, gamete incompatibility prevents the formation of numerous inter-species hybrids.
Genetic Drift
unpredictable fluctuations in allele frequencies from one generation to the next because of a population's finite size
Gradualism
gradualism is a theory which holds that profound change is the cumulative product of slow but continuous processes
Heterozygote Advantage
greater reproductive success of heterozygous individuals compared to homozygotes; tends to preserve variation in gene pools
Homeotic
any of the genes that control the overall body plan of animals and plants by controlling the developmental fate of groups of cells
Hybrid Breakdown
In plants more than in animals, hybrids between closely related species are sometimes partially fertile. Gene exchange may nevertheless be inhibited because the offspring are poorly viable or sterile.
Natural Selection
is the nonrandom process by which biologic traits become more or less common in a population as a function of differential reproduction of their bearers
In a lighter environment natural selection favors lighter moths leading to an increase in populations of white moths and a decrease in black moths
Neutral Variation
hypothesis that much evolutionary change in genes and proteins has no effect on fitness and therefore is not influenced by Darwinian natural selection
you don't live or die or reproduce more or less according to your eye color.
Paedomorphosis
retention in an adult organism of the juvenile features of its evolutionary ancestors
Polymorphism
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species-Dark-morph or melanistic Jaguar (about 6% of the South American population)-Light-morph Jaguar (typical)
Postzygotic Barriers
the inability of the fetus or the zygote to survive once the eggs have been fertilized
Reduced Hybrid Viability
The hybrid is very fragile. The genes of the different parents will interact and impair the hybrids development.
A specific subspecies of salamander live in areas where they occasionally meet and breed. Often times the offspring do not develop fully and those that do are not very fit.
Reduced Hybrid Fertility
The hybrids will survive and live a full life but they are unable to produce offspring
Ligers are infertile
Relative Fitness
describes the ability to both survive and reproduce, and is equal to the average contribution to the gene pool of the next generation that is made by an average individual of the specified genotype or phenotype
The Snowshoe hare is more fit than an animal that lives in the same environment but is less camouflaged
Sexual Dimorphism
polymorphism based on distinction between the secondary sex characteristics of males and females
Sympatric Speciation
speciation occurring as a result of a radical change in the genome of a subpopulation, reproductively isolating the subpopulation from the parent population
Uniformitarianism
Lyell's idea that geologic processes have not changed throughout Earth's history
A photograph shows the current scene (2003), below John Clerk of Eldin's illustration of 1787.