EBIO 1220 1st Edition Lecture 3 Outline of Last Lecture I. Where Does Evolution Come From?II. Mechanisms of Evolutionary Changea. Natural Selectionb. Genetic DrifIII. Evolution in the Wilda. Pocket MiceIV. The Epigenetics Revolutiona. Horizontal Gene Transferb. HumansV. Sexual Selection and Natural Selection Outline of Current Lecture II. Speciationa. What is a Species?III. Species Conceptsa. Biological Species Conceptb. Morphological Species Conceptc. Ecological Species Conceptd. Phylogenetic Species ConceptIV. Barriers to Gene Exchangea. Reproductive Isolationb. Barriers to Gene Flowc. Results of Reproductive IsolationCurrent LectureII. Speciationa. What is a Species?i. Speciation: process by which one population splits into 2+ speciesii. Species: in Latin, “kind” or “appearance”1. Defined using lots of dataa. Morphology- color, body shape, size, etc.b. Physiologyc. Biochemistryd. DNA SequencesIII. Species ConceptsThese 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.a. Biological Species Concepti. States that a species is a group of populations whose members have the potential to interbreed in nature and create viable, fertile offspringii. Most widely usediii. Limitations: hybrids (ligers), organisms that asexually reproduceb. Morphological Species Concepti. States that a species is defined through morphology1. Mopho (shape) and ology (study of)ii. Anything related to appearanceiii. Limitations: males and females ofen look very different within a species, sometimes two different species look very similar1. Can be misleading in many waysc. Ecological Species Concepti. Views a species in terms of its environmentii. Features of ecology1. Two frogs living in very different environmentsiii. Host-parasite relationshipsiv. Insects on plants 1. Apple maggot fly on native species now very different than flies oncultivated speciesd. Phylogenetic Species Concepti. Defines a species as the smallest group of individuals on a phylogenetic treeii. Clustering by similaritiesiii. Genetic and morphological (sometimes) dataiv. Like a family treev. Genetic relatedness to classify speciesIV. Barriers to Gene Exchangea. Reproductive Isolationi. Existence of biological factors/barriers that impede two groups from producing viable, fertile offspring1. Hybrids: offspring of cross b/w two species2. Pre-Zygotic: factors that impede reproduction before fertilization3. Post-Zygotic: factors that impede reproduction afer fertilizationb. Barriers to Gene Flowi. Gene Flow: genetic info from one population exchanged w/ anotherii. Barriers to gene flow1. Human structures2. Changes in geology3. Natural disastersc. Results of Reproductive Isolationi. Isolated populations divergeii. Differences in two populations due to different adaptationsiii. Barriers to gene exchange can disappeariv. Results of disappearing barrier1. New hybrid population could evolve (stability)2. Differences could collapse and two populations could become oneagain (fusion)3. The two populations can no longer breed and gene flow declines between the two distinct populations