BIOL108 Lecture Notes - Lecture 5: Mutation, Mendelian Inheritance, Meiosis

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Lien Luong

Document Summary

Trees that show the relationship between past and present organisms are called phylogenetic trees, phylogeny, and cladograms. Descent with modi cation explains how species change and diversify over time. The process of natural selection gives rise to adaptations. As individuals adapt to di erent environments, new species may arise over time ( over many generations). Natural selection is context-dependent ( no innate tendency towards perfection). Types of heritable variation are form, function, and behaviour. Phenotypic means that it is a trait that can be seen or measured. For natural selection to act on variation, it must be seen by the environment: expressed in the phenotype and heritable by the genotype. Varitation is random, but natural selection is not. Recombination can lead to variation, ex: crossing over. During meiosis, there is an independent assortment of chromosomes, which creates variation. Selective agent is the component of the natural environment that is consistently causing di erential survival and/or reproduction.