PPT-Population Genetics, Speciation, and Classification

Population Genetics Definition study of evolution from a genetic point of view Microevolution Change in the collective genetic material of a population Within a population individuals may vary in observable traits Scientists use a . The rise and fall of biodiversity. Four major . mass extinctions . of marine organisms:. End of Silurian Devonian, Permian, and Cretaceous). Rise in diversity during Cambrian, Silurian, Cretaceous, and Paleogene. Evolution. Results of evolution. New species (speciation). Causes of evolution. Barriers between same species (gene pools). Geographical isolation -> leads to . allopatric. speciation. Temporal isolation -> leads to sympatric speciation. Evolution. Speciation Basics. Individuals of different species cannot . interbreed. under natural conditions . Described as being . reproductively isolated . from one another. Populations of different species do . The rise and fall of biodiversity. Four major mass extinctions of marine organisms:. End of Silurian Devonian, Permian, and Cretaceous). Rise in diversity during Cambrian, Silurian, Cretaceous, and Paleogene. KEY CONCEPTS. • Although many species persist for long periods of time both genotypic and phenotypic changes occur over time.. • Even if change is occurring, individuals that interbreed within a population(s) maintain the status of the population(s) as a species.. Objectives. Identify. traits that vary in populations and that may be studied.. Explain. the importance of the bell curve to population genetics.. Compare . three causes of genetic variation in a population.. Section 1 Vocabulary Pretest. Population Genetics. Microevolution. Gene Pool. Allele Frequency. Phenotype Frequency. Total genetic information in a population. Portion of gene copies of a given allele. Sympatric Speciation. Sympatric Speciation occurs . without. geographic isolation, thus it occurs at a local level. . There is something within the environment that keeps a single species separated into two or more distinct groups.. Species. Part B. How do species occur?. Concept . 24.2: Speciation can take place with or without geographic separation. Speciation can occur in two ways:. Allopatric. speciation. Sympatric . speciation. Gene Pool. All the alleles present in the reproducing members of a population at a given time.. The gene pool is constantly changing. Mutations add new alleles to the population. Immigration also adds new alleles; changes the allele frequency. is concerned with the question of whether a particular allele or genotype will become more common or less common over time in a population, and Why.. Example: . Given that the CCR5-. D. 32 allele confers immunity to HIV, will it become more frequent in the human population over time?. Part 2. Condition 5: . No. Natural Selection. Balanced polymorphism . occurs when natural selection favors heterozygous individuals in a population.. Heterozygotes are selected for by the environment.. . . . Species. . A. . group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. .. Speciation. . It.  is the . evolutionary.  process by which populations evolve to become distinct . Avneet. Singh, Steven . Ancheta. , Giovanni . Corralhejo. , Katie . Laackmann. Definition. Origin of new species in evolution. There are two general modes of speciation. Allopatric. speciation. Sympatric speciation.