Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

At least in some cases, physical proportions affect the probability of survival of a species; specifically they are negatively correlated with the length of existence of a species (Raup 1994). However it is probable that the lower rate of reproduction of large species is important here.This dependence was quite apparent in the Late Pleistocene, although the causes were rather atypical.At that time, primarily large mammals and birds became extinct, specifically species weighing more than 44 kg (Gittleman & Gompper 2001).These species became extinct almost all around the planet over a very short period of time.Simultaneously, this extinction occurred at different times in the individual parts of the world.For example, in North America, this extinction event lasted approximately 200 years, in a period about 10,800 to 11,000 years ago, during which 72% of large animal species and only 10% of small animal species became extinct.This selective extinction was greatest in South and North America, Australia and Madagascar, while Africa and Asia were affected far less.The most probable cause of this extinction, which is also termed Blitzkrieg extinction, was hunting of large animals by humans.The time of disappearance of animals at the individual places correlated very well with the arrival of humans in this territory.The extinction was not so marked in places where settlement occurred gradually or where humans had lived from the very beginning, as the animals apparently had time to adapt to this dangerous predator; in contrast, the extinction was greater in territories that were settled rapidly.

            Greater sensitivity of large animals to extinction was also manifested at other times.It is highly probable that it could be connected with the relatively smaller sizes of the populations of larger organisms.The resistance to extinction is positively correlated with the size of the population and is thus negatively correlated with the size of the members of a particular species.