In this lesson you’ll learn about two terms that describe species with very low population numbers: threatened and endangered. You’ll discover why species numbers decline and how we can keep the species that are threatened or endangered from going extinct.
What Is Extinction?
There are thousands, if not millions, of species of organisms on our planet. Many species that used to exist no longer do; these species are called extinct. The most common example of an extinct species are the dinosaurs. These large animals, which once roamed the Earth, can no longer be found today.
While the dinosaurs became extinct because of a meteor hitting the Earth, humans are the primary cause of species extinction today.
How Do Organisms Go Extinct?
Hunting, deforestation (or chopping down forest for land to build on), and overfishing are all human practices that contribute to the decline in species numbers. When the natural population numbers of a species get low, there are two terms that can be used to describe that species. These are threatened and endangered.
The International Union for Conservation of Nature (IUCN), also known as the World Conservation Union, was founded in 1948 and is primarily responsible for classifying species as threatened or endangered. The IUCN considers a species threatened if the population is vulnerable to endangerment in the near future. A species is considered endangered if the population faces a high risk of extinction. The IUCN has seven different categories in which they classify species. These are:
- Least Concern – There is no immediate threat to the survival of the species.
These are typically common species that have been hunted or can be hunted, but no harm is done to the population as a whole. Examples of these species are the Canadian goose and the American alligator.
- Near Threatened – These are species that could be considered threatened in the near future, and population numbers are monitored carefully. Examples of near-threatened species are the emperor penguin and the American bison.
- Vulnerable/Threatened – These are species that face a high risk of extinction, but not for many years. These species are typically hunted for pelts and trophies – for example, lions for pelts and African elephants for ivory – or have lost a significant amount of their habitat, such as Komodo dragons and Galapagos tortoises.
- Endangered – These organisms face a high risk of extinction in the near future. Examples include Asian elephants, green sea turtles, and blue whales. These populations are closely monitored, and there are considerable fines and jail time if someone is found hunting or harming a species that is considered endangered.
- Critically Endangered – A species in this category is likely to go extinct in the near future unless drastic measures are taken to ensure its survival. Many of these species were over-hunted or over-fished and continue to be hunted illegally, also known as poaching. Examples include the mountain gorilla, bluefin tuna, and the California condor.
- Extinct in the Wild – This means that while no living members of a certain species exist in their native habitat, there are individuals in captivity.
The best example of a species that is extinct in the wild is the northern white rhinoceros. The white rhino was over-hunted and killed for its horn, which is considered to be extremely valuable. In fact, park rangers are now cutting the horns off rhinoceros in the wild so they won’t be killed by poachers.
- Extinct – No living members of these species exist. Examples of organisms that have gone extinct include the previously mentioned dinosaurs, wooly mammoths, and dodo birds. Many of these species we only know existed from fossil records or by finding their bones buried in the ground. These are the animals that you typically see when you visit a natural history museum.
However, there are numerous species that have gone extinct purely from the actions of humans. Some examples include the western black rhinoceros (which was declared extinct in 2011), the Japanese river otter (which was declared extinct in 2012), and the Formosan clouded leopard, which was declared extinct in 2013.
How Are Species Protected?
Each country is responsible for the protection and conservation of their own threatened and endangered species. In the United States, we have the Endangered Species Act, which was put into effect in 1973. Under the ESA, two federal agencies, the United States Fish and Wildlife Service as well as the National Oceanic and Atmospheric Administration, are permitted to fine and arrest anyone who is harming and/or found killing an endangered or threatened animal or plant.
How Do You Keep a Species From Going Extinct?
In order to keep the species that are currently on our planet alive and thriving, scientists focus on conservation.
This includes maintaining the habitat in which these species live as well as the population numbers of the species itself. A number of zoos around the country participate in conservation programs, which try and breed threatened and endangered species in the zoo and then relocate the young to their native habitat later. The San Diego Zoo is well-known for their efforts in successfully breeding the endangered giant panda from China. However, legislation, such as the Endangered Species Act, is also vital in monitoring and listing species that have dwindling population numbers. There are currently 3,079 animals and 2,655 plants species classified as endangered worldwide.
Why Conservation Is Important
You may be asking yourself why keeping plants and animals from going extinct is important. A healthy ecosystem works like a balance; when the weight is equal on both sides, there aren’t any problems. However, if you add weight to one side or another, then the scales tip. In a balanced ecosystem there is enough plant life to sustain the herbivores, or plant-eaters (such as deer), and enough herbivores to sustain the carnivores, such as wolves.But what happens when the population numbers of the predators drastically drop due to hunting, or the weight on one side of the scale is taken away? Then the herbivore population numbers would dramatically increase, which would lead to overgrazing of the plants, which would in turn start to die off.
Then the herbivores wouldn’t have enough food, so their population numbers would start to decline, leaving the remaining predators with nothing to eat. So removing even a single species has the potential to have drastic effects on the ecosystem as a whole.
Species that used to exist and no longer do are labeled as extinct. Before a species goes extinct, it is labeled as being threatened (or is vulnerable to endangerment) or endangered (meaning the population faces the risk of extinction). Today, humans are directly responsible for almost all the threatened and endangered species due to practices such as hunting and overfishing as well as destroying natural habitats to make land for building. Threatened and endangered species are closely monitored by legislation, such as the Endangered Species Act, and those who choose to continue to hunt or harm these protected species face large fines and imprisonment as a consequence.
Protecting endangered and threatened species is extremely important to conservation.
After watching this lesson, you should be able to:
- Identify reasons why species numbers continue to decline
- Define threatened species, endangered species, and extinct
- Explain what the Endangered Species Act (ESA) does
- Discuss why conservation is important to ecosystems