BI301 Lecture Notes - Lecture 11: Ring Species, Paleozoic, Lake Kivu
Document Summary
Natural selection: implications for global ecology & biogeography. Natural selection: basic principals: evolution by the mechanism of natural selection: Individuals vary, and at least some of that variation is inherited. Organisms produce many more offspring than are needed for replacements yet populations generally remain fairly constant. A consistent relationship between the trait and survivorship or reproduction. Inheritance of the trait (a consistent relationship between parents and their offspring) Role of reproduction: origin of sexual reproduction, life cycle variations, asexual reproduction (in good times versus sexual reproduction in. Bad times : replication of dna- mutations can arise, production of gametes -both mutation and recombination can occur, sexual reproduction: life cycles. Important concepts embedded in the three basic life cycle plans: Alternation of generations (flip from haploid to diploid) Meiosis produces gametes; gametes are the only haploid stage. Fertilization produces a diploid zygote (a short-lived stage) Haploid cells undergo growth (via mitosis!) to elaborate spore-producing structures.
