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CHAPTER 23
CHAPTER 23

learning objectives
learning objectives

... 11. Explain why meiosis and random fertilization alone will not alter the frequency of alleles or genotypes in a population. 12. List the five conditions that must be met for a population to remain in HardyWeinberg equilibrium. 13. Write the Hardy-Weinberg equation. Use the equation to calculate all ...
Genetics and evolution
Genetics and evolution

... Genetics and evolution Populations evolve, NOT individuals! Evolution = Helpful definitions Gene pool = A collection of all of the possible genes in a population Allelic frequency = The % of an allele in a gene pool. Genetic equilibrium = Occurs when allele frequency does not change (NO EVOLUTION) ( ...
Evolution - Biology Junction
Evolution - Biology Junction

... 5. Changes in the allele frequency in a small population that is due to random chance & don't follow the laws of probability 6. English economist that reasoned that if the human population kept growing unchecked that there would not be enough food and space 7. Type of selection in which individuals ...
Lecture 10
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... the species are native. • High genetic diversity • In invasions, usually the product of repeated introductions • Higher diversity within populations than between them. This contrast to native range where individual populations are genetically distinct and most variation is between population ...
Allele Frequencies: Changing
Allele Frequencies: Changing

... • More extreme effects: – Smaller number of founders – New population more isolated ...
Allele Frequencies: Changing
Allele Frequencies: Changing

... • More extreme effects: – Smaller number of founders – New population more isolated ...
Chapter 16
Chapter 16

... • Gene flow (gene migration) is the movement of alleles among populations by migration of breeding individuals • Gene flow can increase variation within a population by introducing novel alleles produced by mutation in another population • Continued gene flow decreases diversity among populations, c ...
Evolution II Task Review Answers
Evolution II Task Review Answers

... Variation: differences in alleles/traits in a population Three causes: mutation, recombination, random pairing of gametes When graphed shows a bell curve or normal distribution shape If there was no variation, the species might not be able to adapt to changes in the environment and die out ...
Hardy-Weinberg Equation Notes
Hardy-Weinberg Equation Notes

Genetic Variation is the Key to Natural Selection
Genetic Variation is the Key to Natural Selection

... Genetic Variation is the Key to Natural Selection • Variation is common among populations. • Only genetic variation has evolutionary consequences. ...
Evolution - charlestonbiology
Evolution - charlestonbiology

... only a few individuals gametes forming the next generation.  The two causes of genetic drift are:  Founder effect – a few individuals are dispersed and form an isolated population. They have limited genetic material, rare alleles will have a higher frequency than in the original population.  Bott ...
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lecture26_Polymorphi..

... Edwards AW. 2003. Human genetic diversity: Lewontin's fallacy. Bioessays 25: 798-801 even if the probability of misclassifying an individual’s race based on a single locus is as high as 30%, the misclassification probability based on 10 loci can drop to a few percent ...
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evolution
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A a A A A A A a a a a a a a a A a A A A A A A AA A A a a
A a A A A A A a a a a a a a a A a A A A A A A AA A A a a

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Biology 4974/5974 Evolution
Biology 4974/5974 Evolution

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Changes Over Time - Effingham County Schools

... be less effective, and the frequency of resistant insects in the population ...
III. A. Mechanisms of Evolution 1. Evolution occurs at the population
III. A. Mechanisms of Evolution 1. Evolution occurs at the population

Biology-n15pn.
Biology-n15pn.

... b. Discovered that evolution will NOT occur in a population unless allelic frequencies are acted upon that cause change. ~ex. A change in the number of alleles for red in flowers in a population over the number of recessive white alleles in a population. c. ~when allelic frequencies remain constant, ...
Unit 4 Evolution Study Guide There are five driving forces of
Unit 4 Evolution Study Guide There are five driving forces of

... Homologous character: traits that are similar between different species that signify a common ancestor; example – the bones in bat wings are more similar in arrangement to the bones in a human hand than they are to the bones in a bird wing. This suggests, among other things, a closer common ancesto ...
Ch. 23- Evolution of Populations
Ch. 23- Evolution of Populations

... d) Fossil evidence of horse size increasing over time ...
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Genetic drift



Genetic drift (or allelic drift) is the change in the frequency of a gene variant (allele) in a population due to random sampling of organisms.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces. A population's allele frequency is the fraction of the copies of one gene that share a particular form. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation.When there are few copies of an allele, the effect of genetic drift is larger, and when there are many copies the effect is smaller. In the early twentieth century vigorous debates occurred over the relative importance of natural selection versus neutral processes, including genetic drift. Ronald Fisher, who explained natural selection using Mendelian genetics, held the view that genetic drift plays at the most a minor role in evolution, and this remained the dominant view for several decades. In 1968, Motoo Kimura rekindled the debate with his neutral theory of molecular evolution, which claims that most instances where a genetic change spreads across a population (although not necessarily changes in phenotypes) are caused by genetic drift. There is currently a scientific debate about how much of evolution has been caused by natural selection, and how much by genetic drift.
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