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The Process of Evolution How it Works and How we See It.

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Presentation on theme: "The Process of Evolution How it Works and How we See It."— Presentation transcript:

1 The Process of Evolution How it Works and How we See It

2 Topic Outline Evolution in a Genetic Context Evolution in a Genetic Context - Microevolution - Microevolution Hardy-Weinberg Hardy-Weinberg Causes of Microevolution Causes of Microevolution Natural Selection Natural Selection Types of Selection Types of Selection Maintenance of Variations Maintenance of Variations Speciation Speciation Modes of Speciation Modes of Speciation

3 Background Vocabulary Gene Gene Allele Allele Phenotype vs Genotype Phenotype vs Genotype Homozygous Homozygous Heterozygous Heterozygous Gene pool Gene pool Microevolution Microevolution Polygenic (Quantitative) vs Monogenic Traits Polygenic (Quantitative) vs Monogenic Traits

4 The Hardy-Weinberg Model p 2 + 2pq + q 2 And p+q=1

5 What Does it Mean? p=Frequency of Dominant allele p=Frequency of Dominant allele q=Frequency of recessive allele q=Frequency of recessive allele p 2 =frequency of Homozygous dominant individuals p 2 =frequency of Homozygous dominant individuals q 2 =frequency of homozygous recessive indviduals q 2 =frequency of homozygous recessive indviduals 2pq=frequency of heterozygotes 2pq=frequency of heterozygotes

6 So What? The Hardy-Weinberg principle states an equilibrium of allele frequencies in a gene pool of a sexually reproducing population, p 2 + 2pq + q 2, won’t change as long as certain conditions are met. What are these conditions? The Hardy-Weinberg principle states an equilibrium of allele frequencies in a gene pool of a sexually reproducing population, p 2 + 2pq + q 2, won’t change as long as certain conditions are met. What are these conditions?

7 Example: Industrial Melanism

8 Causes of Microevolution Genetic Mutations Genetic Mutations Gene Flow Gene Flow Nonrandom Mating Nonrandom Mating Genetic Drift Genetic Drift Natural Selection Natural Selection

9 MUTATIONS Gene mutations -- -- the only source of new alleles Gene mutations -- -- the only source of new alleles Chromosomal mutations -- -- alterations in the number, composition, or the arrangement of gene’s on a chromosome Chromosomal mutations -- -- alterations in the number, composition, or the arrangement of gene’s on a chromosome

10 Chromosomal mutations

11 Deletion

12 Translocation

13 Duplication

14 Inversion

15 Gene Flow Physical Movement of Alleles

16 Nonrandom Mating Assortative mating Sexual selection

17 Genetic Drift Genetic Drift Bottleneck Effect Bottleneck Effect Founder Effect Founder Effect

18 Bottleneck Effect

19 Founder Effect

20 Founder Effect 2

21 Natural Selection

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24 Types of Selection Directional Selection Directional Selection Stabilizing Selection Stabilizing Selection Disruptive Selection Disruptive Selection

25 Directional Selection

26 Stabilizing Selection

27 Disruptive Selection

28 Maintenance of Variations Are there any advantages to variation in a population?

29 Sickle Cell Distribution

30 Speciation Species Definition Species Definition Morphological Morphological Biological Biological Reproductive Isolation Reproductive Isolation Phylogenetic Phylogenetic

31 Species A group of interbreeding populations that share a gene pool and are reproductively isolated from other species. A group of interbreeding populations that share a gene pool and are reproductively isolated from other species. Subpopulations can exchange genes. Different species can’t. Subpopulations can exchange genes. Different species can’t.

32 Reproductive Isolating Mechanisms Prezygotic Isolating Mechanisms Postzygotic Isolating Mechanisms

33 Modes of Speciation Allopatric Speciation-spatial separation Allopatric Speciation-spatial separation Sympatric Speciation- no spatial separation Sympatric Speciation- no spatial separation

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36 SYMPATRIC SPECIATION --EX SPECIES A: 2N=14,  N = 7 DUPLICATION SPECIES A’: 2N=28  N = 14 SPECIES A X SPECIES B 2N=21  N=?

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38 Adaptive Radiation

39 Review Evolution in a Genetic Context Evolution in a Genetic Context - Microevolution - Microevolution Hardy-Weinberg Hardy-Weinberg Causes of Microevolution Causes of Microevolution Natural Selection Natural Selection Types of Selection Types of Selection Maintenance of Variations Maintenance of Variations Speciation Speciation Modes of Speciation Modes of Speciation

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