PPT-Speciation The actual “origin of species”

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 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. 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. 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. 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. 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. . Temporal – crickets mature at different times. Prezygotic. isolation. Habitat – land vs. water garter snakes. Prezygotic. isolation. Behavioral – firefly mating. Prezygotic. isolation. Gametic. Sympatric Speciation. Sympatric Speciation occurs . without. geographic isolation, thus it occurs at a local level. . There is something within the environment that keeps a single species separated into two or more distinct groups.. 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 . 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. . After reading this module you should be able to. Explain . the processes of allopatric and sympatric speciation.. U. nderstand . the factors that affect the pace of . evolution.. Speciation can be allopatric or sympatric.