the process of evolution how it works and how we see it

The Process of The Process of EvolutionEvolution

How it Works and How How it Works and How we See Itwe See It

Topic OutlineTopic Outline

Evolution in a Genetic ContextEvolution in a Genetic Context - Microevolution- Microevolution

Hardy-WeinbergHardy-Weinberg Causes of MicroevolutionCauses of Microevolution Natural SelectionNatural Selection

Types of SelectionTypes of Selection Maintenance of VariationsMaintenance of Variations SpeciationSpeciation

Modes of SpeciationModes of Speciation

Background VocabularyBackground Vocabulary GeneGene AlleleAllele Phenotype vs GenotypePhenotype vs Genotype HomozygousHomozygous HeterozygousHeterozygous Gene poolGene pool MicroevolutionMicroevolution Polygenic (Quantitative) vs Monogenic Polygenic (Quantitative) vs Monogenic

TraitsTraits

The Hardy-Weinberg ModelThe Hardy-Weinberg Model

pp22 + + 2pq2pq + + qq22

And And

pp++q=1q=1

What Does it Mean?What Does it Mean?

p=Frequency of Dominant allelep=Frequency of Dominant allele q=Frequency of recessive alleleq=Frequency of recessive allele pp22=frequency of Homozygous =frequency of Homozygous

dominant individualsdominant individuals qq22=frequency of homozygous =frequency of homozygous

recessive indvidualsrecessive indviduals 2pq=frequency of heterozygotes2pq=frequency of heterozygotes

So What?So What?

The Hardy-Weinberg principle states The Hardy-Weinberg principle states an equilibrium of allele frequencies in an equilibrium of allele frequencies in a gene pool of a sexually reproducing a gene pool of a sexually reproducing population, population, pp22 + + 2pq2pq + + qq22, won’t , won’t change as long as certain conditions change as long as certain conditions are met. What are these conditions?are met. What are these conditions?

Example: Industrial Example: Industrial MelanismMelanism

Causes of MicroevolutionCauses of Microevolution

Genetic Mutations Genetic Mutations Gene FlowGene Flow Nonrandom MatingNonrandom Mating Genetic DriftGenetic Drift Natural SelectionNatural Selection

MUTATIONSMUTATIONS

Gene mutations -- -- the only source Gene mutations -- -- the only source of new allelesof new alleles

Chromosomal mutations -- -- Chromosomal mutations -- -- alterations in the number, alterations in the number, composition, or the arrangement of composition, or the arrangement of gene’s on a chromosomegene’s on a chromosome

Chromosomal mutationsChromosomal mutations

DeletionDeletion

TranslocationTranslocation

DuplicationDuplication

InversionInversion

Gene FlowGene FlowPhysical Movement of AllelesPhysical Movement of Alleles

Nonrandom MatingNonrandom Mating

Assortative mating Assortative mating

Sexual selectionSexual selection

Genetic DriftGenetic Drift

Bottleneck EffectBottleneck Effect

Founder EffectFounder Effect

Bottleneck EffectBottleneck Effect

Founder EffectFounder Effect

Founder Effect 2Founder Effect 2

Natural SelectionNatural Selection

Types of SelectionTypes of Selection

Directional SelectionDirectional Selection

Stabilizing SelectionStabilizing Selection

Disruptive SelectionDisruptive Selection

Directional Directional SelectionSelection

Stabilizing Stabilizing SelectionSelection

Disruptive Disruptive SelectionSelection

Maintenance of VariationsMaintenance of Variations

Are there any advantages to variation Are there any advantages to variation in a population?in a population?

Sickle Cell DistributionSickle Cell Distribution

SpeciationSpeciation

Species DefinitionSpecies DefinitionMorphologicalMorphologicalBiologicalBiological

Reproductive IsolationReproductive IsolationPhylogeneticPhylogenetic

SpeciesSpecies A group of interbreeding A group of interbreeding

populations that share a gene populations that share a gene pool and are pool and are reproductively reproductively isolatedisolated from other species. from other species.

Subpopulations can exchange Subpopulations can exchange genes. Different species can’t.genes. Different species can’t.

Reproductive Isolating Reproductive Isolating MechanismsMechanisms

Prezygotic Isolating Prezygotic Isolating MechanismsMechanisms

Postzygotic Isolating Postzygotic Isolating MechanismsMechanisms

Modes of SpeciationModes of Speciation

Allopatric Speciation-Allopatric Speciation-spatial separationspatial separation

Sympatric Speciation- no Sympatric Speciation- no spatial separationspatial separation

SYMPATRIC SPECIATION --EXSYMPATRIC SPECIATION --EX

SPECIES A: 2N=14,SPECIES A: 2N=14,

N = 7N = 7

DUPLICATIONDUPLICATION

SPECIES A’: 2N=28SPECIES A’: 2N=28

N = 14N = 14

SPECIES A X SPECIES B 2N=21SPECIES A X SPECIES B 2N=21

N=?N=?

Adaptive RadiationAdaptive Radiation

ReviewReview Evolution in a Genetic ContextEvolution in a Genetic Context

- Microevolution- Microevolution Hardy-WeinbergHardy-Weinberg Causes of MicroevolutionCauses of Microevolution Natural SelectionNatural Selection

Types of SelectionTypes of Selection Maintenance of VariationsMaintenance of Variations SpeciationSpeciation

Modes of SpeciationModes of Speciation