Type of Species ?

individuals of these groups rarely interbreed, and all their male offspring are sterile.

Aristotle knew it. So did Theophrastus, his student, sometimes called the father of botany. It is not, as they say, rocket surgery.

Natural selection separates incipient species into sibling species, which do not mate at all but which in morphology, or structure and form, are nearly indistinguishable. Sibling species then evolve into morphologically (and taxonomically) different species.

After long and considerable investigation, no surer criterion for determining species has occurred to me than the distinguishing features that perpetuate themselves in propagation from seed.

Because it is often difficult to distinguish between subspecies and stable species, another criterion has been developed that involves a historical, or phylogenetic, dimension.

no matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as to distinguish a species

In this form, a species is separated from another when there is a parental pattern of ancestry and descent.

This was the first recorded biological definition of "species", although the logical term had been used in biological contexts for a long time prior to that. But his was not the traditional view. Following a suggestion of Aristotle that new species were formed by hybridization at water holes in Africa, St Augustine, among others (including one of the translators of the King James Bible), happily accepted that new species could be formed out of old ones.

Speciation may occur in many ways. A population may become geographically separated from the rest of its species and never be rejoined. Through the process of adaptive radiation,

Linnaeus himself, who is sometimes regarded as the originator of species fixism, observed hybridization between two plant species in his own garden, and late in life revised his view that species were as the "Infinite Being" had first created them. Certainly there was no tradition in Christian theological circles that species had to be unchanging before then.

this population might evolve independently into a new species, changing to fit particular ecological niches in the new environment ..

During the Middle Ages, little natural history — or biology as we would now call it — was being done. But there was an exception: the Holy Roman Emperor Frederick II of Hohenstaufen (1194–1250) was a keen falconer, and wrote, literally, the book on it, finding that Aristotle was sometimes a bit too credulous, and worse that he failed to discuss hawks, falcons, and hunting birds.

Never requiring natural selection to complete its reproductive isolation from the parent species. Within the new environment, populations of the new species might then radiate into species themselves.

Frederick had the resources and the time to do a proper study, and he found that bird species were not simple things at all. He settled on interbreeding as a standard. Albert the Great, who had access both to Frederick's falconers and writings, followed this idea.

A famous example of adaptive radiation is that of the Galapagos finches.

Frederick sent envoys to Sweden looking for evidence for or against the idea that the barnacle goose arose out of worms (which is how it got its name). He found no evidence and concluded that the idea was based on ignorance. Albert did breeding experiments and managed to show that the geese laid eggs in the usual manner.

almost as soon as the idea of species-fixism caught on, it was challenged. Linnaeus made the idea popular in his Systema Naturae, the first edition of which was in 1735. In 1745, physicist Pierre Maupertuis argued in his Physical Venus that species did evolve, that they did so through a crude version of natural selection, and that inherited characteristics were passed on in a 3:1 ratio through both mother and father.

In the 18th century, naturalist Carl Linnaeus invented a system for classifying all living species and defining their relationship to one another. In this system, each species belongs to a “genus”, a “family”, an “order”, a “class” a “branch” and a “kingdom”. Even though it has gone through several modifications, the Linnaean system is still used by most scientists today.

Very closely related group that can reproduce among themselves. The domestic cat (Felis domestica) is a species of the genus Felis.

All living things with the same distant ancestor. The cat belongs to the branch of vertebrates, which are animals that have a spinal column.

This level is the broadest category for classifying living things. The cat belongs to the animal kingdom. Biologists identify five kindoms: fungi, monerans (like bacteria), plants, animals and protists, which are single-celled organisms.

This level is the broadest category for classifying living things. The cat belongs to the animal kingdom. Biologists identify five kindoms: fungi, monerans (like bacteria), plants, animals and protists, which are single-celled organisms.

Every living thing has been given a Latin name made up of two words. The first word designates the genus to which the organism belongs; the second specifies the species. The genus and the species are written in italics and the genus is written with a capital letter.

Species, in biology, classification comprising related organisms that share common characteristics and are capable of interbreeding. This biological species concept is widely used in biology and related fields of study. There are more than 20 other different species concepts

biological species concept, the genetic species concept considers which individuals are capable of interbreeding, as well as the amount of genetic difference between populations of that species, but it may also be used to estimate when the species originated.