Download Free Medical Genetic Variation Within a Population PowerPoint Presentation

Genetic Variation Within a Population PowerPoint Presentation

DOWNLOAD MEDICAL POWERPOINT PRESENTATION

About This Presentation

Description : Check out this medical presentation on Genetic Diversity, which is titled "Genetic Variation Within a Population", to know about the genetic variation within a population.

Tags : Genetic Diversity, Population, genetic variation

Published on : Jul 12, 2021 | Views : 1303 | Downloads : 2

Shareable Url :

Embed Code :

Comment

Transcript

Slide 1-

KEY CONCEPT A population shares a common gene pool. 11.1 Genetic Variation Within a Population
Slide 2-

Genetic variation in a population increases the chance that some individuals will survive. Genetic variation leads to phenotypic variation. Phenotypic variation is necessary for natural selection. Genetic variation is stored in a population’s gene pool. made up of all alleles in a population allele combinations form when organisms have offspring 11.1 Genetic Variation Within a Population
Slide 3-

Allele frequencies measure genetic variation. measures how common allele is in population can be calculated for each allele in gene pool 11.1 Genetic Variation Within a Population
Slide 4-

Genetic variation comes from several sources. Mutation is a random change in the DNA of a gene. Recombination forms new combinations of alleles. can form new allele can be passed on to offspring if in reproductive cells usually occurs during meiosis parents’ alleles arranged in new ways in gametes 11.1 Genetic Variation Within a Population
Slide 5-

Genetic variation comes from several sources. Hybridization is the crossing of two different species. occurs when individuals can’t find mate of own species topic of current scientific research 11.1 Genetic Variation Within a Population
Slide 6-

KEY CONCEPT Populations, not individuals, evolve. 11.2 Natural Selection in Populations
Slide 7-

Natural selection acts on distributions of traits. A normal distribution graphs as a bell-shaped curve. Traits not undergoing natural selection have a normal distribution. highest frequency near mean value frequencies decrease toward each extreme value 11.2 Natural Selection in Populations
Slide 8-

Natural selection can change the distribution of a trait in one of three ways. Microevolution is evolution within a population. observable change in the allele frequencies can result from natural selection 11.2 Natural Selection in Populations
Slide 9-

Natural selection can take one of three paths. Directional selection favors phenotypes at one extreme. 11.2 Natural Selection in Populations
Slide 10-

Stabilizing selection favors the intermediate phenotype. Natural selection can take one of three paths. 11.2 Natural Selection in Populations
Slide 11-

Natural selection can take one of three paths. Disruptive selection favors both extreme phenotypes. 11.2 Natural Selection in Populations
Slide 12-

KEY CONCEPT Natural selection is not the only mechanism through which populations evolve. 11.3 Other Mechanisms of Evolution
Slide 13-

Gene flow is the movement of alleles between populations. Gene flow occurs when individuals join new populations and reproduce. Gene flow keeps neighboring populations similar. Low gene flow increases the chance that two populations will evolve into different species. bald eagle migration 11.3 Other Mechanisms of Evolution
Slide 14-

Genetic drift is a change in allele frequencies due to chance. Genetic drift causes a loss of genetic diversity. It is most common in small populations. A population bottleneck can lead to genetic drift. It occurs when an event drastically reduces population size. The bottleneck effect is genetic drift that occurs after a bottleneck event. 11.3 Other Mechanisms of Evolution
Slide 15-

The founding of a small population can lead to genetic drift. It occurs when a few individuals start a new population. The founder effect is genetic drift that occurs after start of new population. 11.3 Other Mechanisms of Evolution
Slide 16-

Genetic drift has negative effects on a population. less likely to have some individuals that can adapt harmful alleles can become more common due to chance 11.3 Other Mechanisms of Evolution
Slide 17-

Sexual selection occurs when certain traits increase mating success. Sexual selection occurs due to higher cost of reproduction for females. males produce many sperm continuously females are more limited in potential offspring each cycle 11.3 Other Mechanisms of Evolution
Slide 18-

There are two types of sexual selection. intrasexual selection: competition among males intersexual selection: males display certain traits to females 11.3 Other Mechanisms of Evolution
Slide 19-

KEY CONCEPT Hardy-Weinberg equilibrium provides a framework for understanding how populations evolve. 11.4 Hardy-Weinberg Equilibrium
Slide 20-

Hardy-Weinberg equilibrium describes populations that are not evolving. Biologists use models to study populations. Hardy-Weinberg equilibrium is a type of model. 11.4 Hardy-Weinberg Equilibrium
Slide 21-

Hardy-Weinberg equilibrium describes populations that are not evolving. Genotype frequencies stay the same if five conditions are met. very large population: no genetic drift no emigration or immigration: no gene flow no mutations: no new alleles added to gene pool random mating: no sexual selection no natural selection: all traits aid equally in survival 11.4 Hardy-Weinberg Equilibrium
Slide 22-

Hardy-Weinberg equilibrium describes populations that are not evolving. Real populations rarely meet all five conditions. Real population data is compared to a model. Models are used to studying how populations evolve. 11.4 Hardy-Weinberg Equilibrium
Slide 23-

The Hardy-Weinberg equation is used to predict genotype frequencies in a population. Predicted genotype frequencies are compared with actual frequencies. used for traits in simple dominant-recessive systems "The Hardy-Weinberg equation is based on Mendelian genetics. It is derived from a simple Punnett square in which p is the frequency of the dominant allele and q is the frequency of the recessive allele." must know frequency of recessive homozygotes p2 + 2pq + q2 = 1 11.4 Hardy-Weinberg Equilibrium
Slide 24-

There are five factors that can lead to evolution. Genetic drift changes allele frequencies due to chance alone. 11.4 Hardy-Weinberg Equilibrium
Slide 25-

Gene flow moves alleles from one population to another. 11.4 Hardy-Weinberg Equilibrium
Slide 26-

Mutations produce the genetic variation needed for evolution. 11.4 Hardy-Weinberg Equilibrium
Slide 27-

Sexual selection selects for traits that improve mating success. 11.4 Hardy-Weinberg Equilibrium
Slide 28-

Natural selection selects for traits advantageous for survival. 11.4 Hardy-Weinberg Equilibrium
Slide 29-

In nature, populations evolve. expected in all populations most of the time respond to changing environments 11.4 Hardy-Weinberg Equilibrium
Slide 30-

KEY CONCEPT New species can arise when populations are isolated. 11.5 Speciation Through Isolation
Slide 31-

The isolation of populations can lead to speciation. Populations become isolated when there is no gene flow. Isolated populations adapt to their own environments. Genetic differences can add up over generations. 11.5 Speciation Through Isolation
Slide 32-

Reproductive isolation can occur between isolated populations. members of different populations cannot mate successfully final step to becoming separate species Speciation is the rise of two or more species from one existing species. 11.5 Speciation Through Isolation
Slide 33-

Populations can become isolated in several ways. Behavioral barriers can cause isolation. called behavioral isolation includes differences in courtship or mating behaviors 11.5 Speciation Through Isolation
Slide 34-

Geographic barriers can cause isolation. called geographic isolation physical barriers divide population Temporal barriers can cause isolation. called temporal isolation timing of reproductive periods prevents mating 11.5 Speciation Through Isolation
Slide 35-

KEY CONCEPT Evolution occurs in patterns. 11.6 Patterns in Evolution
Slide 36-

Evolution through natural selection is not random. Natural selection can have direction. The effects of natural selection add up over time. 11.6 Patterns in Evolution
Slide 37-

Convergent evolution describes evolution toward similar traits in unrelated species. 11.6 Patterns in Evolution
Slide 38-

Divergent evolution describes evolution toward different traits in closely related species. 11.6 Patterns in Evolution
Slide 39-

Species can shape each other over time. Two or more species can evolve together through coevolution. evolutionary paths become connected species evolve in response to changes in each other 11.6 Patterns in Evolution
Slide 40-

Coevolution can occur in beneficial relationships. 11.6 Patterns in Evolution
Slide 41-

Coevolution can occur in competitive relationships, sometimes called evolutionary. 11.6 Patterns in Evolution
Slide 42-

Species can become extinct. Extinction is the elimination of a species from Earth. Background extinctions occur continuously at a very low rate. occur at roughly the same rate as speciation usually affects a few species in a small area caused by local changes in environment 11.6 Patterns in Evolution
Slide 43-

Mass extinctions are rare but much more intense. destroy many species at global level thought to be caused by catastrophic events at least five mass extinctions in last 600 million years 11.6 Patterns in Evolution
Slide 44-

Speciation often occurs in patterns. A pattern of punctuated equilibrium exists in the fossil record. theory proposed by Eldredge and Gould in 1972 episodes of speciation occur suddenly in geologic time followed by long periods of little evolutionary change revised Darwin’s idea that species arose through gradual transformations 11.6 Patterns in Evolution
Slide 45-

Many species evolve from one species during adaptive radiation. ancestral species diversifies into many descendent species descendent species usually adapted to wide range of environments 11.6 Patterns in Evolution