Chapter 23 Notes (Evolution of Populations)
Chapter 23 Notes (Evolution of Populations) BIOL 111 102
Popular in Introduction to Modern Biology
Popular in Science
This 3 page Class Notes was uploaded by Melissa Romano on Wednesday April 27, 2016. The Class Notes belongs to BIOL 111 102 at Camden County College taught by Jill Carroll in Winter 2016. Since its upload, it has received 6 views. For similar materials see Introduction to Modern Biology in Science at Camden County College.
Reviews for Chapter 23 Notes (Evolution of Populations)
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 04/27/16
Chapter 23: Evolution of Populations Microevolution - Changes of allele frequencies within a single population Hardy-Weinberg Principle - Within a population, genotype frequency would remain constant if the following conditions are met: Population size is large Random mating occurs No mutation takes place No new individuals enter the population/no immigration No selection occurs Hardy-Weinberg Equilibrium - O2e gene with 22alleles - P + 2pq + q = 1 - p + q = 1 - p = homozygous dominant parent - 2pq = heterozygous dominant - q = homozygous recessive - 1 = 100% - Determines how often you find an allele within the population Factors that Alter Equilibrium - Mutation Adding new allele Alters gene frequency - Gene Flow Removing/Adding alleles Reduces genetic variety Changes ratio Migration - Random Mating Sexual Selection o Sexual Dimorphism: males/females look different from one another Intrasexual: usually males fighting other males for territory, food, & women Intersexual: usually female picks male mate Genetic Drift (Founder Effect) - What occurs when a population is small - Founder Effect One individual leaves original population to start (found) a new population Can’t represent diversity/variety of the individual’s original population - Bottleneck Effect Population significantly diminishes in size, leaving few survivors Occurs randomly Reason behind many endangered animal species Selection - Directional One phenotype extreme is favored against survival due to environment - Stable Both phenotype extremes favored against survival Median of extremes favored to survive - Disruptive Median phenotype favored against survival Phenotype extremes survive Macroevolution - Speciation: the formation of new and distinct species in the course of evolution - Biological Species Concept: interbreeding that produces fertile offspring Reproductive Barriers - Prevents species from mating - 2 Types: Prezygotic Barriers: zygote never forms/fertilization never occurs Postzygotic Mechanisms: fertilization occurs, problems with zygote after birth Prezygotic Barriers - Habitat - Temporal Isolation Mating season (animals) Plants only reproduce when flowers are bloomed - Behavioral Mating rituals Only applies to animals Ex: Blue Footed Boobie shows off blue feet to attract females - Mechanical Sex/gamete exchange occurs Gamete exchange not always able to occur when desired - Gametic Sperm of one species can’t fertilize eggs of another species Postzygotic Mechanisms - Hybrid Inviability: zygote doesn’t develop - Hybrid Sterility Zygote develops but can’t reproduce Ex: Female Horse + Male Donkey = Sterile Mule Chromosomes too different to pair up and reproduce - Hybrid Breakdown Offspring reproduce but F2 Generation is sterile Ex: Tiger + Lion = Liger (fertile with sterile offspring) Geography of Speciation - Allopathic: physical separation - Sympatric: same area separation (plants) Polyploidy - Only occurs with plants - Triploid Plants Sterile (usually seedless) Ex: seedless watermelon - Tetriploid Plants = fertile Pace of Evolution - Gradualism Darwin Slow, steady changes over time Big changes after long span of time - Punctuated Equilibrium Big changes over short period of time
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'