As well as Darwin, the Reverend J.T. Gulick also found Wagner's theories overstated., but in a later paper Gulick says that "Moritz Wagner, in his "Law of the Migration of Organisms", was the first to insist on the importance of geographical isolation as a factor in evolution, but when he asserted that, without geographical isolation, natural selection could have no effect in producing new species, he went beyond what could be sustained by facts".
Ernst Mayr's formulation cleared up the issues which Wagner had left unresoved: "A new species develops if a population which has become isolated from its parental species acquires during this period of isolation characters which promote or guarantee isolation when the external barriers break down". The zoological taxonomist Bernhard Rensch was also significant in keeping geographical speciation on the evolutionary menu. He identified geographical separation as the most frequent initial step towards "kladogenesis" (species splitting).
The importance of Wagner's insight is undeniable today. It was obscured for many years by his other, mistaken, ideas, but it was a genuine natural history insight gained by observation of insects in their natural habitats.
Africanized bee
Africanized honeybees are an artificial man-made hybrid of the European honeybee and African bees. They are more dangerous and defensive than regular honeybees. Because of this, some people call them 'killer bees'.
Africanized honeybees are much more protective of their beehive and more likely to sting. When one of them is surprised or scared, they all attack together and sting the same animal or person with hundreds of stings. Actually, their sting is the same as a regular honeybee's, but because they sting all together, they are much more dangerous. They usually chase their target much farther than regular honeybees, and they stay angry and ready to fight for a longer time. They have many more "guard" bees than regular honeybees.
In 1956, scientists brought African and European bees to Brazil, to see if they could mate them. They wanted to do this to make a bee that would make more honey in a hotter place. Scientists called these new bees ""Africanized honeybees"". These bees, however, were very different from regular honeybees. They would suddenly leave the colony and build a hive somewhere else. Scientists found out that the queen would decide to leave after a few months, usually taking half the colony with her. They could even take over European hives by killing the European queen bee and making their own queen bee the "queen".
Because of the queen's strange behavior of leaving the hive and starting new colonies, Africanized honeybees spread out quickly from Brazil. They have moved towards the north so that they have spread through most of South America, Mexico, and the south parts of Texas, New Mexico, Arizona, and California. Scientists are not sure how far they will spread. Some think they cannot go much more towards the north, because they do not survive well in really cold winters or extremely dry summers.
Those Africanized bees which have travelled southwards have become much tamer and are well suitable for beekeeping and making honey. The re-domesticated Africanized honeybee is usually the choice of South American beekeepers because it will produce much more honey than the ordinary honeybees. The honey production from a single hive of Africanized honey bees can be 100 kg annually and far exceeds the much smaller 3–5 kg of the various "Melipona" stingless bee species. Thus economic pressures are forcing beekeepers to switch from the traditional stingless bees of their ancestors to the new reality of the Africanized honey bee.
Ipatinga
Ipatinga is a Brazilian city in the Vale do Aço metropolitan area, state of Minas Gerais. Its population in 2009 was 244.508 inhabitants. Its area is 165.509 km². The city was founded in April 29, 1964.
It's limited with Caratinga, Coronel Fabriciano, Mesquita, Santana do Paraíso and Timóteo.
Timóteo
Timóteo is a city in Brazil. It is in the Vale do Aço metropolitan area in the state of Minas Gerais. In 2009, 79,813 people lived there. The city has an area of . The city was founded in April 29, 1964.
Timóteo is ArcelorMittal Timóteo headquarters, a company of the group ArcelorMittal.
It is limited with the municipal districts of Ipatinga, Coronel Fabriciano, Antônio Dias, Jaguaraçu, Marliéria, Caratinga e Bom Jesus do Galho.
Mammal-like reptile
Mammal-like reptile is an old term for the therapsids: those synapsids which gave rise to the true mammals.
The term is both outmoded and a mistake, because mammals did not descend from reptiles. Both groups descended from early amniotes (egg-laying tetrapods), probably in the Lower or Middle Carboniferous. The precursors of reptiles are called sauropsids, and the precursors of mammals are called synapsids. The immediate ancestors of the mammals came from a group of therapsids called the cynodonts.
There are a number of characteristics which cannot be seen on fossils, but which are of great importance.
Mammals are distinguished from reptiles by fundamental differences in the development of the blood system. These differences are such that it would be almost impossible for mammals to be derived from reptiles.
This supports the division of amniotes into sauropsida and synapsida.
Cleidoic egg
The cleidoic egg (from Greek kleistos = closed) is the type of egg which reptiles and birds lay. Mammalian reproduction has evolved from laying cleidoic eggs to live birth. The cleidoic egg is sometimes called the amniotic egg, because it is characteristic of amniotes.
These eggs have a protective shell, and are laid out of water. The shell is porous to air, and may be flexible or calcareous (hard).The calcareous shell prevents the egg from desiccation. The eggs contain all the food the embryo needs to develop into a hatchling. As a result, the amphibian's larval stage, the tadpole, is not needed by reptiles or birds. The special membranes that support these eggs are typical traits of all amniotes, including mammals.
The significance of the cleidoic egg is that it enables reproduction out of, and often away from, water. The cleidoic egg has been called "a private little pond", from the way it gives water and nutrition to the embryo. Cleidoic eggs must have evolved in the early or middle Carboniferous, "after" the early tetrapods evolved, but "before" the amniotes split into sauropsids (reptile ancestors) and synapsids (mammal ancestors).
The basic reproduction strategy of amphibia (frogs, for example), is to lay a huge number of eggs, which are left to their own fate. The strategy of amniotes is to invest more in the production of eggs, lay fewer eggs and take some care of them.
Because the eggs are laid on land, internal fertilisation is needed. Thus, from the initial step of a cleidoic egg comes a number of changes in behaviour. With the changes in behaviour comes better and more flexible brains. Some reptiles, for example, crocodiles and birds, look after and protect their young. Mammals are an extreme case: they carry the protection and nursing of the young much further. All mammals provide milk for their young, and many smaller mammals raise their young in burrows, providing a meaasure of security. Humans go even further still, with the long period of learning before their young are independent. Also, in human evolution, there is a reduction in instinctive behaviour, which is inherited. Instead, there is a great increase in learned behaviours and social life. These later adaptations were made possible by the earlier evolution of the cleidoic egg.