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. 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. 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. 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. Part C. Allopatric. and Sympatric Speciation: . A Review. In . allopatric. speciation, geographic isolation restricts gene flow between populations. Reproductive isolation may then arise by natural selection, genetic drift, or sexual selection in the isolated populations. Part C. Allopatric. and Sympatric Speciation: . A Review. In . allopatric. speciation, geographic isolation restricts gene flow between populations. Reproductive isolation may then arise by natural selection, genetic drift, or sexual selection in the isolated populations. KEY CONCEPTS. • Although many species persist for long periods of time both genotypic and phenotypic changes occur over time.. • Even if change is occurring, individuals that interbreed within a population(s) maintain the status of the population(s) as a species.. Cartoon – gentleman and ape. 2. Key Concepts:. Species concepts. Development of reproductive isolation. Patterns of speciation. Macroevolution. Human evolution. Evolution continues…... 3. specie. Macroevolution. describes the origination of new taxonomic groups (vs . microevolution. , which deals with change in allele frequency, and frequencies of genotype and phenotype). What is a species?. Species. Part B. How do species occur?. Concept . 24.2: Speciation can take place with or without geographic separation. Speciation can occur in two ways:. Allopatric. speciation. Sympatric . speciation. 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 .