PPT-D.2 Species and 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. Speciation. – formation of a new species . 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. Evolution. Results of evolution. New species (speciation). Causes of evolution. Barriers between same species (gene pools). Geographical isolation -> leads to . allopatric. speciation. Temporal isolation -> leads to sympatric speciation. Evolution. Speciation Basics. Individuals of different species cannot . interbreed. under natural conditions . Described as being . reproductively isolated . from one another. Populations of different species do . 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. Concept 22.2: Speciation can take place with or without geographic separation. Speciation can occur in two ways. Allopatric speciation. Sympatric speciation. Allopatric (. “. Other Country. ”. ) Speciation. Species. == “kind” or “type” in Latin. Typological . (morphological) species. . == a group of organisms that share certain characteristics which are different than other groups—usually differences in anatomy. . 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. 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. What defines a species?. Species: a group of organisms that can . interbreed. and produce . fertile. offspring. “Biological Species Concept” . Human species?. Homo sapiens – “wise man” (large brains!). 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. Populations must become isolated. Reproductive isolation is key!. Once isolated, populations will evolve independently (different factors affecting each). Two types of speciation. allopatric. geographic separation. In evolutionary terms a . species . is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with 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. .