BIOL 101 1nd Edition Lecture 22Outline of Last Lecture I. Population GeneticsII. Hardy Weinberg PrincipleOutline of Current Lecture I. Biological Species ConceptII. Reproductive Barriersa. Pre-zygotic Barriersb. Post-zygotic BarriersCurrent LectureThe Origin of Species Class DiscussionI. Concepts of SpeciesA. Ernst Mayr’s Biological Species Concept: a group of populations whose Individuals have the potential to mate and produce viable (fertile) offspring.B. Alternative definitions are needed. Why?Ecological, morphological, we cant always tell if species interbreed and produce fertile offspring. For organisms that are extinct and for organisms that reproduce asexually. C. Reproductive Barriers – why can’t related species mate? 1. Five pre-zygotic Barriers and examples:a. Mechanical isolation – differences in physical structures prevent successful matingb. Habitat Isolation – live in same area but different habitats so don’t encounter each otherc. Temporal isolation – species breed at different times of the day or different seasonsd. Behavioral isolation – different courtship rituals or other behaviors prevent mate recognition between speciesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.e. Gametic isolation – male and female gametes of different species fail to unite, fertilization did not occur2. Three post-zygotic Barriers and examples:a. Reduced Hybrid Viability – the development or survival of hybrids is impairedb. Reduced Hybrid Fertility – hybrids fail to produce functional gametesc. Hybrid Breakdown – offspring of hybrids are feeble or
View Full Document
Unlocking...