Whatever the case, experts believe that today's extinction rate is hundreds, if not thousands, of times more than the natural baseline rate. According to the fossil record, the baseline extinction rate is one species per million species each year. But during the past few million years, several studies have shown that this rate increased by at least an order of magnitude, with some researchers estimating that it may have been as high as 10,000 times the background rate.
There are many factors that can increase the extinction rate beyond what is normal for a given period and location. Humans have played a role in many recent extinctions, but they also have been responsible for saving many others. Climate change can lead to long-term changes in habitat availability and quality, which will be important for species that depend on certain conditions for survival. Overhunting can cause populations to collapse, leaving only the most adaptable species with no genetic diversity. All of these factors can work together to drive out vulnerable species.
Extinction is typically divided into three main categories: natural extinctions, human-induced extinctions, and conservation extinctions. Natural extinctions happen when a species dies out due to changing environmental conditions or because it is unable to compete with other species for food, water, or shelter. Overhunting is a major factor in driving out many species of fish, bird, and mammal.
The present rate of extinction is up to 10,000 times greater than the historical norm. We, the humans, are virtually entirely to blame for this growth. In fact, if current trends continue, then within a few hundred years we will have wiped out humanity itself.
The main driver of extinction rates is the impact of humans on species via hunting and habitat loss. For example, 85% of all male lions in South Africa were killed between 1950 and 1980. Extinction rates can also be increased by invasive species, pollution, and war. Invasive species are organisms that are introduced into an environment where they aren't naturally found, such as cats being introduced into islands to control rodent populations. They can have negative effects on native species due to competition for food, space, or predators. Pollution refers to the harmful effect of chemicals released into the air, water, or soil. These chemicals can enter animals through their mouth or skin, or even through food chains. War has been implicated in the extinction of numerous species. For example, there has been significant controversy over whether conflict with humans is responsible for the extinction of some tribal groups.
The best way to avoid extinctions is not to go beyond the planet's ability to support human life.
According to these researchers, between 0.01 and 0.1 percent of all species will die extinct each year. If the low estimate of the number of species is correct—that there are around 2 million distinct species on our planet**—then between 200 and 2,000 extinctions occur each year. This does not include species that become extinct due to human activity.
** The number of species on Earth has been estimated to be around 7 million. Of these, it is believed about 1 million have been described by scientists so far. A third of those are insects.
Extinction rates vary across the tree of life. For example, mammals are likely to go extinct more rapidly than plants because they use up critical resources that other organisms can exploit. Also, parasites and predators tend to have higher extinction rates because they are typically beaten out by faster evolving competitors or killed off entirely when their prey or predator species go extinct. Organisms with large populations and slow reproduction rates, such as elephants and gingko trees, are likely to survive longer than small-population species with fast reproduction rates, like dandelions. But overall, species are going extinct at a rate of about one per year, which is similar to the rate over most of history.
Half of all species may become extinct by the end of the century. The pace of species extinction is up to 10,000 times faster than it was in the past. More than one in every five species on Earth is on the verge of extinction, and this figure is expected to climb to 50 percent by the end of the century unless immediate action is taken.
Scientists have estimated that there are more than 5 million species on Earth. Of these, about 1 million are described as "vulnerable" and another 300,000 are considered "near threatened." That's about 8% of all living organisms, or one in 12 creatures on Earth. And among those, it's been estimated that half a million species are at risk of extinction within the next 100 years.
The main cause of species extinction is thought to be human activity. Humans are causing climate change, which is leading to environmental changes that can potentially harm species evolutionarily close to them (i.e., cousins). In addition, humans are also killing off species through hunting and deforestation, with the aim of replacing them with domesticated plants and animals. This is called "domestication."
Another factor contributing to species extinction is disease. Some diseases are caused by parasites that infect animals or plants, while others are caused by bacteria that infect both animals and plants. Disease can kill millions of people each year and cause widespread devastation of crops, livestock, and forest land.
However, if the highest estimate of species counts is correct—that there are 100 million distinct species coexisting with humans on our planet—then 10,000 to 100,000 species become extinct each year. That's a lot! Scientists think that most species go extinct because they lose their habitats due to human activity. Humans also take advantage of the most vulnerable species - those who can't be easily replaced like endangered animals and plants - putting them at risk of extinction.
On top of that, scientists have estimated that between 50,000 and 70,000 species become extinct every year. This is called "the biggest extinction event in human history" or "the sixth mass extinction". The five previous events caused by humans happened before we started making an impact on climate change. So, this one is mainly due to us!
Of these hundreds of thousands of species, about half have been identified by scientists as being close to extinction. The others will be lost forever unless we do something about it. The good news is that most species don't need to be saved; only a few are important for people to survive. In fact, some scientists believe that all life forms on Earth would suffer if all species were to disappear.
We know how many species there are on Earth today thanks to scientists who have conducted surveys across the world's ecosystems.
Every 24 hours, 150-200 species of plants, insects, birds, and animals go extinct, according to scientists. This is roughly 1,000 times the "normal" or "background" rate and, according to many biologists, is bigger than anything the earth has seen since the dinosaurs were extinct 65 million years ago.
This number comes from research conducted by Carl Buell at the University of California, Berkeley, who estimates that there are about 5 million species on earth today and that they disappear from the planet at a rate of 1% per year. He calculates that if this rate remains constant, then between 50-200 species will go extinct each day.
However, this estimate is based on studies done on living organisms, which means it cannot be applied to those species that have gone extinct. So, for example, if we know that the woolly mammoth died out around 12,000 years ago, then how can we say with any certainty that another mammal won't become extinct tomorrow? The fact is that we don't know what happened to most of the species that have gone extinct over time, so we can't make any predictions about what will happen to future ones.
Furthermore, not all species are equal. Some are more vulnerable to extinction than others. For example, insect species tend to go extinct faster than other types of animal due to their small population sizes and lack of evolutionary resistance.