Galaxy, universe and the planet Earth, as well as the others planet, are in constant process of change. Every living part has some kind of energy. Energy is a fundamental entity of nature that is transferred between parts of a system in the production of physical change within the system and usually regarded as the capacity for doing work. It means that energy is meant to be non-permanent. Change is natural process, in which nothing is permanent, constant. If we think of the Earth and the ecosystem as something which is in constant change, than we can understand that extinction is a natural part of life on Earth. Over the history of the Planet, most of the species that ever existed, evolved and than gradually went extinct. For example 70% of the North American large mammal genera went extinct at the end of the last ice age. So what is the reason for today species extinction?
Human activity. Even though some species are predetermine to extinct, but they are not to extinct so fast. And there are many species that would without human activity for another hundreds of years joining worlds ecosystem. Today species are going extinct at accelerated and dangerous rate, because of non-natural environmental changes caused by human activities. Some of the activities have direct effects on species and ecosystem: habitat loss, overexploitation (overfishing), spread of non-native species/diseases, some indirect but wide-reaching effect on biodiversity: climate change and pollution. All of these threats have put a serious strain on the biodiversity of species on Earth. According to the International Union for Conservation of Nature (IUCN), globally about one third of all known species are threatened with extinction. That includes 29% of all amphibians, 21% of all mammals and 12% of all birds. If we do not stop the threats to biodiversity, we could be facing some another mass extinction with terrible consequences to the environment.
But thinking about this issue, we have to consider as well natural shifts in environment that take place over long periods of time, such as ice ages. Now the planet Earth is in the interglacial period, so we have to allow that some species had to go extinct, and now is turn of some others.
Paleontologist estimate that most species “last” from 1 to 10 million years. So if we assume there are 10 million species, 1 to 10 species goes to extinct each year (0,00001% – 0,0001% per year). This rate might be considered as normal, natural rate according to which we can measure today’s mass extinctions. Global biodiversity has reached an all time high in present geological period about 30 000 years ago. Since than the biodiversity declined mostly because of the human activity.
Cultural evolution allow the rapid spread of new technologies and over few centuries humans became super-predator capable of hunting, mining and the most dangerous thing for our planet – overexploiting almost everything, any prey. And species are not able to respond via biological evolution when extinct. Extinction rate is now documented to be about 2 species per year.
Evidence from the fossil record suggest that there have been at least 5 mass extinctions during the Earth’s history. Assuming that less well known taxa has similar rates, we are experiencing the sixth mass extinction of life on Earth.
So why should we be concerned about modern extinctions, if it is a natural process?
- The extinction rate today is at much higher level that the expected natural rate. At this level, the ecosystem is not capable to recover or the species are not allowed to adapt.
- The primary cause of extinction is human impact, corresponding today’s lifestyle.
Throughout the centuries, we can see increasing human activity and decreasing capability of ecosystem to work and act natural. Many years of pollution have result in huge impact on ecosystem and biodiversity. It’s slowly and unstoppable ruining nature and it will never be the same. Some scientist say, that all the things we have done to our Earth can’t be reverse, we can just slow down and postpone completely damage of ecosystem. Climate change as effect of pollution, overexploitation, deforestation, urbanization, etc. has terrible and huge impact of every aspect on Earth. For example the agriculture is becoming unsustainable due to the climate change, urbanization and irresponsible way of farming.
There is no single factor responsible of extinction. Some species may gradually reduce in number over thousands of years as they are crowded out and competed by another species. Others may become extinct very suddenly due to an unprecedented event, such as a large-scale fires or natural disasters. Internationally, habitat loss and degradation is considered the most significant factor. Other factors include over-exploitation, pollution, disease and climate change. Some species may be affected by a combination of factors. Species that have a very limited habitat or small population size are particularly vulnerable to extinction.
Conclusion : Species extinction at natural rate is consequence of natural process, but mass extinction in today’s world is caused by human activity. It’s necessary to slow down the process of mass species extinction and to precede biodiversity loss.
 A grouping of organisms given a formal taxonomic name, such as species, genus, family, etc.