Mass Extinctions and Loss of Biodiversity
Despite being aware of biodiversity importance for quite a long time, human beings have been creating massive extinctions through various activities. Mass extinction involves a decline or death of certain species globally, and in large number, over duration of time. Some of the events that result in mass extinction are the cataclysms, which contributed largely in the mass extinction, where three-quarters of the planet’s life disappeared. Mass extinction led to the desertion of dinosaurs owing to the interference of their food chain. Increase in carbon dioxide within the atmosphere has also contributed in extinction of dinosaurs.
The core cause of the current mass extinction is human activities that include deforestation and burning of fossils. Such activities have resulted in change of climate due to massive release of carbon dioxide gas into the atmosphere, which threatened most animal and plant species. According to Biello, humans have contributed in the extinction of roughly 1,000 species for the last 200,000 years (par. 3). Even before civilization, humans had already contributed to the extinction of the wooly mammoths and giant kangaroos. The current extinction rate could be relatively high due to overlooking of certain species like beetles, which are not useful to humans.
Specifically, some of the human activities that have resulted in the reduction of the biodiversity within the planet include exploitation of land to build cities, clearing of land for settlement, and killing some animals for food. Such activities have contributed in mass extinction of animals and plant species. For several centuries, humans have been interfering with the ecosystem, leading to the disappearance of certain species, such as beetles and insects while the population of humans has continued to rise. Large animals, such as elephants and tigers are at a great risk of extinction due to overexploitation for food and habitat destruction.
Mass extinction can be prevented if humans take necessary precautions to save the biodiversity. Biello proposes gradual decline in fishing to save most species of fish and reforestation of tree species to save wildlife (par. 7). Reforestation has helped in the return of woodlands, which host coyotes, turkeys, deer, and other animals that survive in the forests. In extreme case, humans can engage in bringing back new animals to replace those that have gone extinct, such as relocating tortoise from Seychelles to Mauritius to restore the island ecosystem.
Part 2: Historical Mass Extinctions
Several mass extinctions events have taken place throughout the Earth’s history, but the most recognized event was the Cretaceous-Tertiary, which wiped out all dinosaurs in the planet. The impact events theory explains the causes of mass extinction by stating that a large meteor generated a huge shockwave that disrupted the climate through dust. Change in climate led to a massive extinction of some species globally, most of the flowering plant species also became extinct while others continued to decline gradually for millions of years. The drastic fall of the sea level was also blamed for the extinction.
The Late Devonian mass extermination led to three-quarters of the Earth’s species dying over a period of many years. Organisms that dwelled in the shallow seas became the culprits owing to lack of oxygen and fall in the sea levels. According to climate change theory, the Earth’s climate turned from ice age to a tropical heat, which could not support the life of numerous species. Later on, the tropical heat turned persisted into steamy jungles and eventually to searing deserts.
Biello, David “Fact or Fiction?: The Sixth Mass Extinction Can be Stopped” Scientific American, July 25, 2014. Web. 2 Sept. 2016 www.scientificamerican.com/article/fact-or-fiction-the-sixth-mass-extinction-can-be-stopped/