PPT-15.2 Species and Speciation Overview

Evolution Results of evolution New species speciation Causes of evolution Barriers between same species gene pools Geographical isolation gt leads to allopatric speciation Temporal isolation gt leads to sympatric speciation. What is a Species?. Speciation. – the origin of new species. The . biological species concept. defines a species as a population or group of populations whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring, but who cannot produce viable, fertile offspring with members of other species. The rise and fall of biodiversity. Four major . mass extinctions . of marine organisms:. End of Silurian Devonian, Permian, and Cretaceous). Rise in diversity during Cambrian, Silurian, Cretaceous, and Paleogene. Macroevolution is essentially the formation of new species (speciation) and accompanying events. . Reproductive isolation can occur in a variety of ways. Reproductive isolation is the key to cladogenic speciation. I. Species Definitions. Species represent the boundary for the spread of alleles . and define the unit in which the modes of evolution operate. Biological Species Concept. Individuals belong to the same species if they can interbreed with each other. Phenetic. species concept. : A species is a set of organisms that look similar to each other and distinct from other sets (Sokal and Crovello 1970)..  . Species definitions. Phenetic. species concept. Species. – group of organisms that interbreed and produce fertile offspring. Subspecies. – groups that are on the way to being separate species; have started being genetically different. Individuals in the same species share a common gene pool. Temporal – crickets mature at different times. Prezygotic. isolation. Habitat – land vs. water garter snakes. Prezygotic. isolation. Behavioral – firefly mating. Prezygotic. isolation. Gametic. Learning Goal: . To explore the factors leading to the evolution of a new species. . Success Criteria:. I know I am succeeding when I can… . define the concept of speciation. identify the modes of speciation. Gene Pool. All the alleles present in the reproducing members of a population at a given time.. The gene pool is constantly changing. Mutations add new alleles to the population. Immigration also adds new alleles; changes the allele frequency. Reduction in . gene . flow, genetic and phenotypic change in populations. The study of speciation requires that species be real. Speciation. Speciation is the antidote to sex. Keeps together adaptive groups of traits. I. Species Definitions. Species represent the boundary for the spread of alleles . and define the unit in which the modes of evolution operate. Biological Species Concept. Individuals belong to the same species if they can interbreed with each other. (Unit 10, species concept. Sympatric speciation . Sympatric speciation, (from the Greek ‘same place’) involves the splitting of an ancestral species into two or more reproductively isolated groups without geographical isolation of those groups.. Science. Lesson 8: challenge answer. Investigate and make note of other species that have evolved due to parapatric speciation. . Typically seen in species of fish.. Learning intention. To know what sympatric speciation is and how it occurs. . Microevolution to Macroevolution. Biological Species . Reproductive Isolation. A group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring. The existence of biological factors (barriers) that impede members of two species from producing viable, fertile, offspring.