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Natural selection

Explore the mechanisms of evolution including natural selection, genetic drift, and speciation. Dive into evidence from direct observation, the fossil record, homology, and biogeography to support the theory of evolution.

patrickrodriguez
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Natural selection

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  1. Natural selection • The process by which traits become more or less common in a population through differential survival and reproduction

  2. Adaptive radiation • A form of divergent evolution in which there is rapid speciation of one ancestral species to fill many different ecological niches

  3. Evolution is not perfect • Selection can act only on existing variations • Evolution is limited by historical constraints • Adaptations are often compromises • Chance, natural selection, and the environment interact

  4. 1. Direct observation2. The fossil record3. Homology4. biogeography • Identify the 4 major types of evidence to support the theory of evolution.

  5. .49.59.41 A population of rabbits may be brown (the dominant phenotype) or white (the recessive phenotype). Brown rabbits have the genotype BB or Bb. White rabbits have the genotype bb. The frequency of the BB genotype is .35. • What is the frequency of heterozygous rabbits? • What is the frequency of the B allele? • What is the frequency of the b allele?

  6. Founder effect • Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original position

  7. Sexual dimorphism • Marked differences between the two sexes in secondary sexual characteristics, which are not directly associated with reproduction or survival

  8. Speciation in which the populations are physically separated. A term for physically separated populations. Allopatric

  9. species • Group or population of individuals that can interbreed to produce viable offspring

  10. Homeotic gene • Any of the master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate of groups of cells

  11. Reduced hybrid viability • The genes of different parent species may interact in ways that impair the hybrid’s development or survival in it’s environment

  12. Convergent evolution • The evolution of two or more lineages towards similar morphologies or adaptations so that the lineages appear similar despite their different ancestry

  13. homology • Similarity between species that results from common ancestry

  14. Vestigial structures • Structures that have apparently lost all or most of their original function in a species through evolution

  15. speciation • The division of one species, during evolution, into two or more separate species

  16. Punctuated equilibrium • Periods in the fossil record of apparent stasis punctuated by sudden change

  17. Phylogenetic species concept • A species is the smallest group of individuals that share a common ancestor, forming oine branch on the tree of life

  18. Gene flow • Genetic exchange between populations tends to reduce differences between populations over time.

  19. Identify 5 conditions to maintain Hardy Weinberg Equilibrium • No mutations • Random mating • No natural selection • Extremely large population • No gene flow

  20. Bottleneck effect • Genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions. Typically, the surviving population is no longer genetically representative of the original population

  21. Temporal isolation • Species that breed during different times of the day, different seasons, or different years cannot mix their gametes

  22. Morphological species concept • A species is characterized by structural features • Can be applied to sexual and asexual organisms

  23. evolution • Changes in gene pools over time

  24. mutation • the ultimate source of new alleles

  25. Hybrid breakdown • Some first generation hybrids are viable and fertile, but when they mate with one another or with either parent species, offspring of the next generation are feeble or sterile

  26. Jean-Baptiste de Lamarck • Use and disuse • Inheritance of acquired characteristics

  27. Intersexual selection • Selection whereby individuals of one sex are choosy in selecting their mates from individuals of the other sex • Also called “mate choice”

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