Animal extinctions can be caused by natural events such as climate warming or cooling or changes in sea levels. In recent times, however, human activity has been responsible . Habitat destruction as agricultural land is expanded and forests are cut down is the leading cause of modern extinctions, along with pollution, the introduction of alien species, and overfishing or hunting.
The extinction of an animal species occurs when the last individual member of that species dies. Although a species may be “extinct in the wild,” the species will not become extinct until each individual, regardless of location, captivity, or reproductive capacity, has died.
Most of the extinct species became extinct as a result of natural causes . But we have already seen that other animals, such as the homing pigeon, became extinct due to human-caused habitat loss and overhunting. Man-made environmental issues are also creating serious challenges for several endangered or endangered species.
The non-profit organization Endangered Species International estimates that 99.9% of the animals that once existed on Earth have become extinct due to catastrophic events that occurred while the Earth was evolving. When these events cause animals to die, it is called mass extinction. There have been multiple mass extinctions due to natural cataclysmic events.
While previous mass extinctions occurred long before recorded history, many scientists believe that we are immersed in one: the sixth mass extinction of flora and fauna. There have been no mass extinctions in the last 500 million years, but now that human activities are affecting Earth, extinctions are occurring at an alarming rate.
A normal rate of extinction, due to natural causes, is 1 to 5 species per year. However, with human activities such as the burning of fossil fuels and the destruction of habitats, we are losing species of plants, animals and insects at an alarmingly rapid rate. Scientists at the Center for Biological Diversity estimate that the rate is a thousand more, or even ten thousand more, than 1 to 5. They believe that dozens of animals are going extinct every day.
The largest species rapidly heading towards extinction are amphibians. When frogs and other amphibians begin to die in large numbers, other species fall into a domino effect. Save the Frogs, an organization dedicated to understanding the threat to frogs and other amphibians, estimates that a third of species are already on the threshold of extinction.
