Lecture 04 Outline Chapter 23

Lecture 04 Outline - Chapter 23 The Evolution of Populations Lecture 4 SLIDE 1 Microevolution changes in the genetic makeup of a population from

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Chapter 23: The Evolution of Populations Lecture 4. SLIDE 1 Microevolution: changes in the genetic makeup of a population from generation to generation – leading to phenotypic changes Macroevolution: speciation & evolution that occurs above the species level SLIDE 2 Gregor Mendel‟s experiments showed the PARTICULATE nature of heredity Parents pass on DISCRETE HERITABLE UNITS (GENES) 1. Genes are paired variants (alleles ) that are segregate when gametes are formed and rejoin at fertilization 2. Segregation of one set of alleles has no influence on the segregation of others (independent assortment) ************** Review Chapter 13-14 in Campbell on genetics terms. Make sure you know what the following are! Genotype Phenotype Mitosis Meiosis Genes Loci (locus) Somatic cells Homologous pairs Sex cells Zygote Allele Mutation ************* SLIDE 3 THE PRINCIPLES OF HEREDITY: In a nutshell: GENES are located at specific places (LOCI) on chromosomes: each gene has a LOCUS. SOMATIC CELLS (body cells) are DIPLOID: 2 copies of each chromosome (HOMOLOGOUS PAIRS). Somatic cells produced via MITOSIS. e.g. Human somatic cells: 2 copies of 23 chromosomes (2n = 46)
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GERM CELLS (sperm and eggs) are HAPLOID: 1 copy of each chromosome – They are manufactured by MEIOSIS e.g human egg. n = 23, sperm n = 23. FERTILIZATION forms zygote 2n = 46. cell division by mitosis preserves diploid number SLIDE 4 ALLELES are alternative versions of a gene at a given locus (2 or more in heterozygotes) on each pair of HOMOLOGOUS CHROMOSOMES. New ALLELES arise from MUTATION of other alleles, and are initially rare SLIDE 5 Microevolution: Microevolution –change in allele frequencies in a population over time Natural selection acts on individuals. . Impacts survival/reproductive success of individuals … But: Populations evolve, individuals do not POPULATION – a localized group of interbreeding individuals GENE POOL – total aggregate of ALLELES in a population GENOTYPE – the particular ALLELES in an individual
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This note was uploaded on 11/08/2011 for the course BSC 2011C taught by Professor Klowden/crampton during the Fall '11 term at University of Central Florida.

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Lecture 04 Outline - Chapter 23 The Evolution of Populations Lecture 4 SLIDE 1 Microevolution changes in the genetic makeup of a population from

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