Lab 8 Intro Genetics and Evolution

Evolution Gradual changes in a species over time What’s the evidence?

Fossils Fossils show us gradual changes –Horse example looked at hoof development –p 203

Comparative Anatomy Homologous Structures- –Similar bone structure, different functions –pp

Evidence: Embryological Development (p ) Embryos look similar in closely related organisms Demonstrate links between taxa –Echinoderm larvae are bilaterally symmetrical –Mollusca trochopore larvae are similar to Annelidia

Evolution via Natural Selection 1.Overproduction 2.Variability 3.Differential Survivorship –Those with better adapt traits survive longer and reproduce more 4.Gradual Change –Selection pressures lead to change –Competition, predation, climate, amount of water

Genetics & Variation Genes vs Alleles Genes –are instructions on how to make proteins or traits Alleles –Different version of the same gene

Genetics Variation Dominant vs Recessive Dominant Alleles- –An allele that is always expressed when present Recessive Allele- –Is not expressed when there is a dominant allele –Needs two copies of the recessive allele to be expressed R= Round r= Wrinkled

Genetics & Variation Each organism has 2 copies of every gene –Exceptions are found in plants and fungi One copy comes from each parent

Genetics & Variation Wife’s Mother Wife

Genetics & Variation Bowman’s Brother

Variation and Evolution Multiple alleles = multiple phenotypes. Creates variation within population or species

Allele frequency graph Change in the frequency alleles over time No ChangeChanging

Hardy-Weinberg Principle Allele Frequencies remain stable over long- term unless: 1.Mutation 2.Gene Flow (Immigration or Emigration) 3.Genetic DriftGenetic Drift 4.Nonrandom Mating (sexual selection, unequal sex ratio, etc…) 5.Natural Selection

Genetic Drift Random loss of alleles Go To Simulation: Run the simulation with different population sizes (10 times for each population size).

Make sure you read Read –p (Intro and Darwin) – (Evidence for Evolution to end) Do Activities –p208 Genetic Drift (click here)Genetic Drift (click here) –p209 Pepper Moth (click here)Pepper Moth (click here) –p210 Florida Panther (click here)Florida Panther (click here) –p212 Fuchsia (click here)Fuchsia (click here) Turn in Postlab 8 (given to you last week)