Ever since life started on earth, mass extinction has been occurring. The rapid disappearance of species was ranked as one of the planet's gravest environmental worries, surpassing pollution, global warming and the thinning of the ozone layer, according to the survey of 400 scientists commissioned by New York's American Museum of Natural History (Warrick, Washington post, 1998). The word extinction describes the situation in which something stops existing. And it can be anything, whether a species of animal or a particular kind of plant, or even a tribe. The following context can make us understand the concept well: the tigers in the Indian forest of 'Gir' are on the verge of extinction. Recently, a Caribbean monk seal was announced extinct which is very sad news. Smaller extinction events constantly occur without us knowing, but mass extinction impacts the earth on a whole and adds a very great risk of destruction.
Young people have no respect for authority nowaday...
Prehistory of West Virginia
Extinction eventAfter that even games have come out based on these movies. Mass extinctions, in particular, has been said to have occurred five times, which are classified as major ones, while some say seven. Moreover mass extinctions have usually been followed by mass speciations which indicate that evolution is related to extinction. Mass extinction means the reduction in the number of species in a relatively short period of time. The major extinction events which occurred were, The End Ordovician, Late Devonian, End Permian, End Triassic, and End Cretaceous. The others are the Holocene extinction, which is still occurring and the Permian and Vendian mass extinctions. Other smaller extinctions have also been recorded. (Col, 2008; Elredge, 1991)The Precambrian era was a period in earth history before the evolution of hard-bodied and complex organisms. Throughout the extent of both periods, dominant Precambrian and Vendian organisms were soft-bodied, simple, and entirely marine. Diversification of...