BIOL108 Lecture Notes - Lecture 5: Chromosome, Directional Selection, Disruptive Selection

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Heather Proctor

Document Summary

Fossils in deeper layers of rock (older) are different than fossils in less deep layers (earlier: cuvier explained this by catastrophism events in the past occurred suddenly/different mechanisms. For example, a flood destroying many species: hutton suggests that valleys were formed by corrosion of rivers; lyell proposes uniformitarianism, stating the mechanisms of change are constant over time, lamarck proposes use and disuse; inheritance of acquired characteristics. For example, a giraffe will stretch its neck to adapt to eat food, and pass on this adaptation to its offspring: lamarck"s theory is wrong. A population evolves over time: natural selection can only occur if individuals in a population are not genetically identical. Example of natural selection: soapberry bugs have beak lengths adapted to the depth of the seeds in the trees, penicillin-resistant bacteria are much more common today. Evolution of populations: microevolution, evolution in its smallest scale, is defined as change in allele frequencies over generations, genetic variation allows evolution.