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Diversity Of Life: 2

A deck of flashcards for Undergraduate Study of Biology. Source: Wikipedia

QuestionAnswer
Population Genetics Study of how populations change genetically over-time.
Population A group of interbreeding individuals in the same area.
Phenotype Morphology, physiological and biochemical makeup (genes/genotype and environment).
What factors cause variation? Phenotype and genotype.
Phenotype variation The range of differences in the phenotype of individuals in the population.
Genotype variation The range of differences in the genotype (genetic makeup) of individuals in the population.
Genes It is the specific region of DNA molecules, usually in the form of alleles.
Gene Pool It is the sum of all genes present in the gene pool.
Allele frequency It is the frequency of allele expression in a population
Do individuals evolve? No, only populations evolve.
When does Evolution occur? Evolution occurs when allele frequency changes in a population over-time.
What 2 process results in change? Mutation and sexual recombination.
Mutation It is the change in DNA nucleotide sequence which causes a change in alleles.
Sexual recombination It is the shuffling of alleles during meiosis.
What is the rate of mutation? It has a low rate of 1/10000 genes per generation.
What type of mutation is inherited? Mutation at the gametes are inherited, not mutations in somatic cells.
What are the effects of mutation Mutations may be disadvantageous, neutral or beneficial.
How may mutation be disadvantageous? It may be disadvantageous when it makes an individual less adapted to its environment.
How may mutation be neutral? It may be neutral when there is no effect in reproductive succession/adaptation/natural selection.
How may mutation be beneficial? It may be beneficial when it makes an individual more adapted to its environment. This occurrence is very rare.
Why is sexual recombination an important source of variation? It is important because phenotypic variations are based on genetic differences result from recombinational shuffling of existing alleles in the gene pool.
Genetic equilibrium It is when there is no changes in alleles. Since there is no genetic variation, no evolution will occur.
The Hardy-Weinberg principle A 5 condition principle made by Godfrey Hardy (mathematician) and Wilhelm Weinberg (physician) on the criteria for evolution to occur.
What are the conditions included under the Hardy-Weinberg principle? For evolution not to occur there must be no mutation, the population must be infinitely large, no immigration from other pother populations (no introduction of new alleles), random mating (no preference) and equal survival of all individuals.
Natural Selection It is defined as the increased reproduction of individuals that have phenotypes that are better adapted too survive and reproduce in a particular environment. It is the primary mechanism of evolution.
What is meant by the differential success in reproduction? It means that the variations that are better adapted tend to produce more offspring.
Environment It is the external factors that effects an organism which is both physical (temperature, humidity and etc) and the biotic (predators, food sources, competition and etc)
What are the two types of fitness? Darwinian fitness and relative fitness.
Darwinian fitness It is the genetic contribution of an individual to the next generation's gene pool relative to the average for the population, usually measured by the number of offspring or close kin that survive to reproductive age.
Relative fitness It is the survival and/or reproductive rate of a genotype (or phenotype) relative to the maximum survival and/or reproductive rate of other genotypes in the population.
What are the modes of natural selection? Directional selection, disruptive selection and stabilizing selection
Directional selection This is common during environmental change/where the bell curve shifts to one direction.
Disruptive selection This is when extreme phenotypes are favored rather than intermediate phenotypes.
Stabilizing selection This is when intermediate phenotypes are favored rather than extreme phenotypes.
Gene flow Gene flow causes a gain or loss of alleles in a population. Intermingling causes minimize differences in populations due to a smaller gene flow.
Genetic drift Genetic drift is the random change in the frequency of alleles over time through generations. Often occurs by chance.
What can the genetic drift cause? It causes the increased likelihood of the bottleneck effect and the founder effect.
The bottleneck effect This is the sudden change in environments which cause a drastic reduction of a population (i.e. through a bottleneck). The alleles present in surviving populations are by chance.
The founder effect This is the migration of a small population to a new area previously inhabited by a species. If no immigration from the same population, it would cause a rapid evolution of the new population with a smaller gene pool/allele frequency than the original.
Non-random mating Mating is often non-random and competitive. Individuals with higher chances of mating would leave more offspring. This suggest preference of phenotypes/sexual selection according to mate's choice.
Sexual dimorphism Caused by sexual selection. It results in phenotypic differences in characteristics.
Does natural selection only eliminate unfavorable alleles? No, they may also maintain it, particularly heterozygote advantages where heterozygotes are better than homozygotes.
Balanced polymorphism The maintenance of two or more alleles through many generations.
Created by: theecloud