1 / 40

Understanding Evolution: Process, Genetics, and Speciation

Explore the fascinating process of evolution in a genetic context, from microevolution and Hardy-Weinberg to natural selection, speciation, and maintenance of variations. Learn about key vocabulary and concepts like gene flow, genetic drift, and different types of selection. Understand the Hardy-Weinberg model and its equilibrium principles. Discover how mutations, gene flow, nonrandom mating, and genetic drift contribute to microevolution. Dive into the mechanisms of speciation, including allopatric and sympatric speciation, and adaptive radiation.

pmarsha
Download Presentation

Understanding Evolution: Process, Genetics, and Speciation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

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

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

  4. The Hardy-Weinberg Model p2 + 2pq + q2 And p+q=1

  5. What Does it Mean? • p=Frequency of Dominant allele • q=Frequency of recessive allele • p2=frequency of Homozygous dominant individuals • q2=frequency of homozygous recessive indviduals • 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, p2 + 2pq + q2, won’t change as long as certain conditions are met. What are these conditions?

  7. Example: Industrial Melanism

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

  9. MUTATIONS • Gene mutations -- -- the only source of new alleles • 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 • Bottleneck Effect • Founder Effect

  18. Bottleneck Effect

  19. Founder Effect

  20. Founder Effect 2

  21. Natural Selection

  22. Types of Selection • Directional Selection • Stabilizing Selection • Disruptive Selection

  23. Directional Selection

  24. Stabilizing Selection

  25. Disruptive Selection

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

  27. Sickle Cell Distribution

  28. Speciation • Species Definition • Morphological • Biological • Reproductive Isolation • Phylogenetic

  29. 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.

  30. Reproductive Isolating Mechanisms Prezygotic Isolating Mechanisms Postzygotic Isolating Mechanisms

  31. Modes of Speciation • Allopatric Speciation-spatial separation • Sympatric Speciation- no spatial separation

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

  33. Adaptive Radiation

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

More Related