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Speciation is the evolutionary process by which populations evolve to become distinct species.The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within lineages.
Controversy exists as to whether Charles Darwin recognized a true geographical-based model of speciation in his publication On the Origin of Species. [5] In chapter 11, "Geographical Distribution", Darwin discusses geographic barriers to migration, stating for example that "barriers of any kind, or obstacles to free migration, are related in a close and important manner to the differences ...
Scientists now have a good understanding of the origin of new species and have observed the speciation process in the laboratory and in the wild. Evolution is the principal scientific theory that biologists use to understand life and is used in many disciplines, including medicine , psychology , conservation biology , anthropology , forensics ...
Many proponents of animal rights hold that if animals and humans are of the same nature, then rights cannot be distinct to humans. Charles Darwin, in fact, considered "sympathy" to be one of the most important moral virtues — and that it was, indeed, a product of natural selection and a trait beneficial to social animals (including humans ...
Generally, sympatric speciation in animals requires the evolution of both genetic differences and nonrandom mating, to allow reproductive isolation to evolve. [218] One type of sympatric speciation involves crossbreeding of two related species to produce a new hybrid species. This is not common in animals as animal hybrids are usually sterile.
[134] [135] Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book The Origin of Species. [136] Speciation depends on a measure of reproductive isolation, a reduced gene flow. This occurs most easily in allopatric speciation, where populations are separated geographically and can diverge gradually ...
Sociobiology is a field of biology that aims to explain social behavior in terms of evolution.It draws from disciplines including psychology, ethology, anthropology, evolution, zoology, archaeology, and population genetics.
Reticulate evolution can happen between lineages separated only for a short time, for example through hybrid speciation in a species complex. Nevertheless, it also takes place over larger evolutionary distances, as exemplified by the presence of organelles of bacterial origin in eukaryotic cells. [2]