EESA01H3 Lecture Notes - Lecture 8: Allopatric Speciation, Binomial Nomenclature, Ecosystem Diversity
11 Nov 2016
School
Department
Course
Professor
Document Summary
Eesa01h3 f: lecture 8 - biodiversity and conservation. Evolution: results from random genetic changes across generations, which may proceed randomly or be influenced by natural selection. Natural selection: is the process by which traits that enhance survival and reproduction are passed on more frequently to future generations, altering the genetic makeup of populations of organisms over time. This is based on an organism"s ability to adapt, due to their mutations being either selected for or selected against. Directional selection: is when the extreme phenotypes are favored over other phenotypes. This causes the allele frequency to shift frequently over time in the direction of that extreme phenotype. Thick snail shells are favored over thin shells. Stabilizing selection: is a form of natural selection where genetic diversity decreases and the population mean stabilizes on a particular trait value. Shells that are too thin break and those that are too thick are heavy.
