20 Facts on Species Extinction: What I Should Know

(Photo: NHNZ)

Firstly, scientists don’t know and probably will never know how many species of animals, fungi, bacteria, and plants are there on Earth. Or even how many are there have already extinct.

How could extinction happen? Extinctions happen when a species dies out from many causes such as evolutionary problems, cataclysmic events, environmental factors, or human interference. But to some extent, extinction is natural. And now, human civilization has harmed most living things.

So, how can we talk about how much we’re losing and what causes it? Scientists do have lots of facts, figures, and scientific analyses to indicate it. Here are some facts on species extinction especially on animal extinction that we should know.

Where are we?

1. We are amidst the largest period of species extinction in the last 60 million years

Normally, one to five species will go extinct each year. But scientists have estimated that now we are losing species at a much higher rate than the normal rate. It is 1,000 to 10,000 times than the normal rate.

2. It’s widely believed that the sixth mass extinction is underway

The sixth mass extinction is an ongoing species extinction event during the present Anthropocene or Holocene epoch that resulted from human activity. It’s the sixth in roughly 540 million years. And there is no single mass extinction events of geological history for which a single species (humans) appears to be highly responsible.

Although scientists agree that now Earth is suffering the sixth mass extinction, they disagree about its consequences. This misunderstanding ignores some critical issue.

The current period isn’t an inevitable consequence of the evolution process. Rather, it’s the result of the quick change in the environment that many organisms couldn’t evolve and adapt fast enough to it. Extinctions occur. But not suddenly and nearly universal as is happening right now.

How many are there?

3. There are around 2 to 100 million different species on our planet

There are between 1.4 and 1.8 million species have already been scientifically identified. It includes around 50,000 vertebrate species (of which some are 4,000 mammals and 10,000 birds), 4 to 8 million insects, and 300,000 plant species.

Some also believed 100 million different species are co-existing with us on this planet. Moreover, researchers from the University of Arizona estimated that there are around 2 billion living species on Earth. One thing scientists generally agree that there are way more species exist than are formally described.

How many are we losing?

4. 10,000 to 100,000 species go extinct every year

It’s impossible to know exactly how many species go extinct every year. According to scientific analysis, the current extinction rate is between 1,000 to 10,000 times higher than the normal rate. And between 0.01 and 0.1% of species will go extinct each year.

Using the low estimation, there are around 200 to 2,000 extinctions occur every year. Using the upper estimation, there are around 10,000 to 100,000 species that go extinct annually.

Some scientists predict that by 2100, all living species could be gone by 50% from pollution, land clearing, and overfishing.

5. In the last 500 years, 869 species have been forced to extinction

Human activity or extinction in the wild is known to have forced the extinction of 869 species in the last 500 years. While 290 more species are considered critically endangered and possibly extinct.

But only 2.7% of the approximately 1.8 million described species have been analyzed by the IUCN. Even though this number is a gross underestimate, it does provide a useful snapshot of what is happening.

How fast is it?

6. The current extinction rate is up to 10,000 times higher than the normal rate

Humans are almost wholly responsible for the increase in species extinction rates. The current rate maybe 10,000 times the background extinction rate according to one scientist estimation. Although most scientists predict lower extinction rates as low as 1,000.

Background extinction rate is what experts called the natural extinction rate. The rate of occurred species extinctions if humans were not around.

What species?

7. Within the next 15 to 40 years, it’s likely animals such as tiger, elephant, polar bear and many more will become extinct

Animals such as tiger, elephant, polar bear, giant panda, chimpanzee, orangutan, mountain gorilla, snow leopard, rhino, and the koala bear will likely become extinct within the next 15 to 40 years.

8. 25% of mammals are now threatened with extinction

It is best estimated that 1 in 4 or about 25% of the world’s mammals are now considered as threatened by The IUCN Red List of Threatened Species. In 2019, there are 5,801 species of mammals assessed and 1,220 of them are threatened.

9. 60% of primates are now threatened with extinction

Almost 90% of the world’s primate population lives in the tropical forest, which is disappearing fast. Around 60% of the known 504 primates are threatened with extinction because of unsustainable human activities. And 75% of primate species populations are declining globally.

Primates are one of the most species-rich groups of mammals, surpassed only by Chiroptera and Rodentia. They are present naturally in 90 countries across the world, but two-thirds of all species present in just four countries: Brazil, Madagascar, Indonesia, and the Democratic Republic of the Congo.

10. 14% of birds are now threatened with extinction

Birds may act as a significant indicator for monitoring biosphere changes. It is because they are usually the most visible and familiar wildlife to humans. They also present in almost all habitats on Earth.

It is best estimated that 1 in 8 or about 14% of the world’s birds are now considered as threatened by the IUCN Red List. In 2019, there are 11,126 species of birds assessed and 1,492 of them are threatened.

The biggest threats bird population facing are habitat degradation and loss, collectors activities, and invasive species.

11. 40% of amphibians are now threatened with extinction

It is best estimated that 1 in 3 or about 40% of the world’s amphibians are now considered as threatened by the IUCN Red List. In 2019, there are 6,771 species of amphibians assessed and 2,157 of them are threatened.

The threats are coming from animal agriculture, habitat loss, global warming, air and water pollution, disease, the introduction of exotic species, and UV light exposure. Amphibians is overly sensitive to environmental change.

12. One-fifth of reptiles are now threatened with extinction

Around 1 in 5 of all known reptile species in the world are now considered endangered or close to being extinct. So far, there are at least 28 island reptiles that have disappeared.

The main crisis that faced by reptile species are habitat loss, the competition of resources or feed with non-native species, and human intervention. Continental habitats fragmentation is caused by human intervention. It resulting in the isolation of species among each other.

13. One-fifth of fishes are now threatened with extinction

Around one-fifth of all known fish species are now considered to be at risk of extinction. About 1 in 5 of the world’s sharks are being threatened with extinction.

The threats that faced by aquatic ecosystems are fishing, water pollution, rising water demand, invasive species, and river dams.

14. One-third of the known invertebrates are now threatened with extinction

It estimated that 97% of all animal species on Earth are invertebrates, from mollusks to butterflies to earthworms to corals. And one-third of them are now threatened with extinction.

The threats come in many forms, such as pollution, water projects, and groundwater withdrawal that threaten freshwater, also animal agriculture and deforestation.

15. 75% of insect populations in Germany have decreased over 27 years of study

A 2017 peer-reviewed study has analyzed that flying insect biomass in Germany has a seasonal decline of 76% and a mid-summer decline of 82% over the 27 years of study from 1989 to 2016.

It’s bad because there are 87.5% of flowering plants species that rely on pollination from insects like bees. Furthermore, there are 60% of recognized 8,600 bird species that rely on insects for food.

16. A lot of the IUCN Red List species threatened percentage can not be estimated yet because of insufficient coverage

Vertebrates such as reptiles and fishes, and invertebrates such as insects, mollusks, crustaceans, and others still not having enough number of evaluated and assessed species from the estimated number of the species.

The result, the IUCN Red List can not give the best estimate of how much species are threatened by each category. To take an example, there are estimated to be 34,200 species of fishes in the world and yet we’ve only evaluated 54% of it.

What causes it?

17. Human activities also cause species loss

According to WWF, the main causes of species loss are habitat loss, unsustainable trade, bycatch, climate change, invasive species, pollution, and human-animal conflict. Even more, are hunting and the rapid growth of the human population.

Climate change, habitat destruction, and exploitation are driving the loss of half of the world’s wild animal population. The food we eat, the things we buy, the land we use, the waste we produce, and much more activities all contribute to this.

18. 99% of currently threatened species are at risk from human activities

It said that human beings could be the greatest threat to biodiversity by the early 21st century. Around 99% of threatened species are now at risk because of human activities. Primarily, caused by habitat loss, the introduction of exotic species, and global warming.

19. Primates are now threatened with extinction because of unsustainable human activities

The main threats to primate species according to the IUCN are loss of habitat due to agriculture (76% of species), logging and wood harvesting (60%), and livestock farming and ranching (31%). Other threats, such as hunting and trapping (60%) and road construction, mineral drilling, and mining (2 to 13%). There are also emerging threats from pollution and climate change.

Is it getting worse?

20. The loss of biodiversity is projected to continue and even accelerate

Human activity and climate change are believed to be the cause, for example through the destruction of coral reefs and forests.

Last updated on December 29, 2019

References:
• Earth Day Network. 2018. “Fact Sheet: Global Species Decline.” May 18. →
• National Geographic. 2019. “Extinct Species, Facts and Information.” February 5. →
• The International Union for Conservation of Nature (IUCN). 2007. “Species Extinction – The Facts.” The IUCN Red List of Threatened Species™. →
• World Animal Foundation. “Extinction Facts by World Animal Foundation.” →