Paleontologists know that in the history of the Earth there are important moments when the rate of extinction increase. For example, scientists have identified five major mass extinctions: five events over the last half a billion years old when more than three quarters of the planet was extinct in a short time. Unfortunately, today we are witnessing another mass extinction because the rate of extinction increased dramatically over the last century.
Death is the inevitable end of life, says a paleontologist at the University of Kansas Luke Strotz. And this is true for all types. According to various estimates, 99.99% of all ever existing are now extinct. All species that exist today — including humans — will also inevitably die out in one the most beautiful moment.
But what factors make a particular species more or less vulnerable to extinction? The rate of extinction vary between the different animal groups and over time, so not all species are equally susceptible to this. Scientists have done a great job documenting extinction, but to determine the processes that lead to extinction, were much more difficult.
By studying modern examples, we find some obvious kinks in the story that had led to the extinction of species. One of these factors is the reduction in the number of species. To the extent that it reduces the number of individuals of a species, reduced genetic diversity and the species becomes more susceptible to random catastrophic events. If the remaining population of the species is small, one forest fire, or even random variation in the sex ratio could eventually lead to extinction.
Why endangered species?
The extinction that occurred in the past, are getting more attention — all are sad Dodo, thylacine or a wandering dove. But the vast majority of extinctions occurred long before humans. Thus, the fossilized annals are the main source of data on extinction.
When paleontologists examine fossils in the context of what we know about the past state of the world, emerges a clearer picture of the early, which leads to the disappearance of species. To date, the probability of extinction of a species is related to several factors.
We certainly know that one important element is temperature. Almost every major rise or fall in global temperatures in the history of the Earth led to the extinction of various organisms.
The size of the geographical area occupied by the species, is also important. Species that are widely distributed will not be less likely than those that occupy a small area or habitat which is separate.
There are also random phenomena that lead to extinction. The meteorite, which led to wymiany 75% life at the end of the Cretaceous period, including the flightless dinosaurs, the best example of this. This random aspect in the extinction leads to the fact that it is often survival of the lucky not the fittest to live.
Not so long ago paleobiology found physiological component of extinction. It turned out that the typical metabolic rate for both fossil and living species of mollusks strongly predicts the likelihood of extinction. The metabolic rate is defined as the mean rate of absorption and distribution of energy in individuals. Clams with higher levels of metabolism are more prone to extinction than those with lower.
Returning to the metaphor of “survival of the fittest/luckiest”, it can be assumed that sometimes survives and the lazy. Higher levels of metabolism correlate with higher mortality as in mammals and fruit flies, so the metabolism can provide important control of mortality at different biological levels. Because metabolic rate is associated with a number of characteristics, including growth rate, maturation time, maximum life span and maximum size of the population, it seems likely that the nature of any or all of these traits plays a role in how vulnerable a species to extinction.
And no matter how much scientists knew about the propulsion of extinction, there are also many unknown. For example, some species dying out, regardless of any serious environmental or biological shocks. It’s called the background rate of extinction. Because paleontologists pay more attention to mass extinction, background extinction rates determined bad. How strong or weak varies this figure, known not very well. And, in General, most extinctions probably falls into this category.
Another problem is to determine how important changes in biological interactions in the explanation of extinction. For example, the extinction of species can occur when increased competition or predator will thrive or disappear when critical prey species. The fossil record, however, rarely captures this information.
Even the number of extinct species can be a mystery. We know very little about current or past biological diversity of microorganisms, such as bacteria or archaea, not to mention any of the facts of the disappearance of these groups.
The biggest mistake we could make, appreciating and explaining the extinction can be related to the approach that tries to bring everything under one framework. The vulnerability of one particular species to extinction is changing with time, and different biological groups respond differently to changes in the environment. While major changes in global climate led to the extinction of some biological groups, the same events eventually led to the emergence of many new species.
So whether the vulnerability of one particular type a result of human activities or climatic changes, this remains an open question.
It is clear that current rates of extinction far exceed all that can be called the background level, and we are on the verge of the sixth mass extinction. Therefore, the question of the vulnerability of any particular species — including our own — need to respond quickly if we want to preserve future biodiversity.
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All existing species, including human, will one day disappear
Ilya Hel