PHIL 1100 Lecture 4: Historical Evolution
21 Nov 2017
School
Department
Course
Professor
Document Summary
Each generation many more offspring are produced than can survive. Subset of individuals that survive are not random. Essentially: natural selection occurs when heritable variation leads to differential success. Adaptation - heritable trait that increases the fitness of an individual in a particular environment relative to individuals lacking the trait. Adaptations occur through inheritance of acquired characteristics: use and disuse - parts become stronger, inheritance of acquired characteristics. If beneficial mutations occur may increase in frequency from natural selection. Mutations don"t occur because they want to adapt. Acquired change is not passed to offspring. Populations evolve not individuals from change in allele. Species not static but change through time. Species show varying degrees of relatedness not independent. Pseudoextinction: species disappears, changed into one or more species. Characteristics in fossil between young and old. Structure and behaviour unused because reduced use. Observation: more similar species tend to be formed in same geographic regions.
