SB

Chapter 13

Key Concepts in Evolution

  • Introduction to Evolution

    • WHO's 1960s malaria campaign used DDT.

    • Mosquito populations evolved resistance to DDT.

    • Chloroquine resistance in malaria parasites mirrors this pattern.

    • Evolution provides foundational knowledge across biology.

  • Darwin's Theory of Evolution

    • Charles Darwin's work, "On the Origin of Species," introduced natural selection.

    • Evolution involves descent with modification, connecting species through common ancestry.

    • Darwin's theory generates hypotheses supported by significant evidence.

  • Evidence from Fossils

    • Fossils document life forms, showing evolution and extinction patterns.

    • Transitional fossils demonstrate links between extinct and modern species.

  • Homologies in Evolution

    • Homologies showcase structural similarities indicating common ancestry.

    • Vestigial structures exemplify remnants of past functions.

    • Evolutionary trees visualize descent patterns among species.

  • Natural Selection

    • A key mechanism driving evolution.

    • Influenced by artificial selection – breeding traits within species.

    • Focuses on heritable traits and populations rather than individual organisms.

    • Natural selection impacts phenotype distribution (stabilizing, directional, disruptive).

  • Microevolution Factors

    • Influenced by mutation, genetic drift, and gene flow.

    • Genetic drift effects: bottleneck and founder effects.

    • Natural selection leads to adaptive evolution while maintaining genetic diversity through mechanisms like heterozygote advantage.

  • Challenges of Evolution

    • Evolution doesn't produce perfection. It acts on existing variations and historical constraints.

    • Examples include adaptations often being compromises rather than ideal functions.