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9.9 Endangered Species

7 min readjanuary 15, 2023

Jenni MacLean

Jenni MacLean

Riya Patel

Riya Patel

Jenni MacLean

Jenni MacLean

Riya Patel

Riya Patel

Classification

Any organism including plants or animals can become endangered. Organisms are classified by the International Union for Conservation of Nature (IUCN) into the following categories. 

https://upload.wikimedia.org/wikipedia/commons/thumb/0/00/Schematic_of_categories_to_classify_ecosystems_according_to_the_IUCN_Red_List_of_Ecosystems_criteria.png/1280px-Schematic_of_categories_to_classify_ecosystems_according_to_the_IUCN_Red_List_of_Ecosystems_criteria.png

Image Courtesy of Wikimedia

Extinct (EX) – These species no longer exist and have become extinct.

Extinct in the wild (EW) – Survives only in captivity, cultivation and/or outside the native range, as presumed after exhaustive surveys.

Critically endangered (CR) – These species are at an extremely high risk of extinction in the wild and their population is declining at an alarming rate.

Endangered (EN) – These species are at a very high risk of extinction in the wild and their population is declining rapidly.

Vulnerable (VU) – Meets one of the 5 red list criteria and thus considered to be at high risk of unnatural (human-caused) extinction without further human intervention.

Near threatened (NT) – These species are at risk of becoming endangered in the near future.

Least concern (LC) – These species are considered to have a low risk of extinction and are not considered endangered.

Conservation Status Classification

IUCN uses five criteria to classify organisms and assess their . The of a species refers to its risk of extinction in the wild. These criteria are:

A) Reduction in population: The population size of the species has decreased significantly over a certain period of time.

B) Geographic range: The species has a restricted geographic range or habitat.

C) Population size: The species has a small population size, estimated to number fewer than 2,500 mature individuals, and is in decline.

D) Extremely small population size: The species has an extremely small population size, estimated to number fewer than 250 mature individuals.

E) : A quantitative analysis has shown that the probability of the species becoming extinct in the wild is at least 20% within 20 years or five generations.

These criteria are used to classify species into the different categories of the IUCN Red List, such as Least Concern, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, and Extinct. The criteria are intended to provide a consistent and objective way to assess the of a species, and to help prioritize conservation efforts.

Check out https://www.iucnredlist.org to look at the population status of thousands of plants and animals.

Risk Factors

Certain organisms are inherently more at risk for extinction than others due to their biology and ecology. The difference in reproductive rate, as well as the ability of an organism to adapt to environmental change, are two key factors that can influence the survival and extinction risk of a species.

, such as mice, have a high reproductive rate and can quickly rebound from population losses. These species are typically short-lived and have many offspring that have a low chance of survival.

, such as elephants, have a lower reproductive rate and take longer to recover from population losses. These species are typically long-lived and have fewer offspring that have a higher chance of survival.

, such as orangutans, have a very specific niche and are adapted to a particular set of conditions. They can be particularly vulnerable to environmental changes and pressures, such as habitat loss, as they may not be able to adapt to new conditions.

, such as pigeons, are able to adapt to a variety of different climates, food sources, and environmental challenges. They tend to be more resilient to environmental changes and pressures, but they can also compete with native species and alter the ecosystem.

Overharvesting

Hunting, fishing, and other forms of harvesting are the most direct human influences on wild populations of plants and animals. occurs when individuals are removed from a population at a rate faster than the population can replace them. This can lead to population declines and even extinction, as seen in the case of the dodo bird on Mauritius.

Historically, market hunting has led to the of many species, such as the American bison and passenger pigeon, causing dramatic declines in population numbers. However, with the implementation of regulations and legal protections, many species have been able to recover, such as the American bison.

Regulations such as hunting and fishing restrictions and limits on the number of animals that can be harvested have been implemented in many countries to prevent . However, in some regions of the world, harvest regulations are not enforced, and continues to threaten species with extinction.

Illegal harvesting of rare animals, such as tigers, rhinoceroses, and apes, and rare plants, birds, and coral reef dwellers for private collections has become an increasing problem, and it's threatened the persistence of these species.

Plant/Animal Trade

The trade in plants and animals can represent a serious threat to the persistence of some species. Laws such as the in the United States and the United Nations Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) were developed to control and regulate the trade of threatened and endangered plants and animals.

The , first passed in 1900, originally prohibited the transport of illegally harvested game animals across state lines. Today, the Act prohibits the interstate shipping of all illegally harvested plants and animals. CITES is an international agreement among 182 countries worldwide, which aims to control the international trade of threatened and endangered species.

Despite these laws and agreements, illegal trade in plants and animals continues to occur worldwide. Illegal trade in wildlife is estimated to be worth between 5 billion to 220 billion dollars annually. Illegal trade in wildlife and wildlife parts have been sent to United States ports over a 10-year period. The illegal trade in wildlife is driven by demand for fur, body parts thought to have medicinal value, and rare animals as pets.

Even legal trade in certain species can pose a potential long-term threat to species persistence. In the southwestern United States, for example, the growing movement to reduce water used by replacing grass lawns with desert landscapes has led to an increased demand for cacti and other desert plants collected from the wild, causing concern for these plant populations in the wild.

Conservation

Countries have implemented a variety of strategies to address the decline in species and protect endangered and threatened species. One of the most important strategies is the implementation of legislation to protect habitats. The Endangered Species Act of 1973 in the United States, for example, aims to protect endangered and threatened species by preserving habitats from development.

Endangered Species Act

The Endangered Species Act (ESA) of 1973 is a federal law in the United States that aims to protect and recover species that are in danger of extinction throughout all or a significant portion of their range. The Act is administered by the U.S. Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration (NOAA) and it is one of the strongest laws in the world for protecting endangered and threatened species.

The ESA provides for the listing of species as either "endangered" or "threatened" based on their risk of extinction. Once a species is listed, the Act requires the federal government to take actions to protect and recover it. This includes the designation of "critical habitat," which is defined as specific areas that are essential for the conservation of the species, as well as the prohibition of harming the listed species and their trade, including their fur or body parts.

The Act also implements the international CITES agreement, which regulates the trade of threatened and endangered species. To assist in the conservation of threatened and endangered species, the Act authorizes the government to purchase habitat that is critical to the conservation of the species and to develop recovery plans to increase the population of threatened and endangered species.

The ESA has been the center of much debate and controversy in recent years, as it can restrict certain human activities in areas where listed species live, including how landowners use their land. Despite this, the Act has had significant success in protecting and recovering endangered and threatened species, with several species being removed from the list as their populations have increased. However, efforts to weaken the ESA have been ongoing and it's important to continue to support and advocate for its protection.

Education

Another key strategy is education, raising public awareness about the potential extinction of species and the impact of human actions on biodiversity. Through education, people can learn about the importance of conservation and take steps to support it.

Breeding Programs

Captive breeding programs in zoos and aquariums can also play a role in species conservation. These institutions can serve as education centers, while at the same time using the animals in captive breeding programs to rebuild populations of critically endangered species. Programs like the Smithsonian National Zoo and the San Diego Zoo have been instrumental in establishing populations of species like the black-footed ferret, red panda, and clouded leopard.

Organizations

In addition, conservation organizations, non-governmental organizations, and research institutions have been working in collaboration with governments to address the decline in species, through research, monitoring, and conservation actions in the field, and also by creating , corridors, and reintroduction programs.

Key Terms to Review (17)

Conservation status

: The conservation status refers to the assessment of how threatened a species is with extinction. It takes into account factors such as population size, geographic range, and habitat quality.

Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

: CITES is an international agreement between governments aimed at ensuring that international trade does not threaten the survival of wild animals and plants. It regulates the trade of certain species by listing them under different appendices based on their level of protection.

Critically endangered (CR)

: Critically endangered is the highest risk category assigned to species that are facing an extremely high risk of extinction in the wild. These species have very small populations or are experiencing a rapid decline in their population size.

Endangered Species Act (ESA)

: The Endangered Species Act (ESA) is a law in the United States that aims to protect and recover endangered and threatened species and their habitats. It provides legal protection for these species, prohibits activities that harm them or their habitats, and promotes conservation efforts.

Extinct (EX)

: Extinct refers to a species that no longer exists anywhere on Earth. It means there are no living individuals left, and the species has completely disappeared from the planet.

Extinct in the wild (EW)

: Extinct in the wild refers to a species that no longer exists naturally in its native habitat but continues to survive only through captive breeding programs or reintroduction efforts.

Generalist species

: Generalist species are organisms that can adapt and thrive in a wide range of environmental conditions and can consume various types of food.

Illegal poaching

: Illegal poaching refers to the illegal hunting, capturing, or killing of wildlife, usually for commercial purposes. It involves the exploitation of protected species and can have severe ecological consequences.

International Union for Conservation of Nature (IUCN)

: The International Union for Conservation of Nature (IUCN) is an international organization that assesses the conservation status of species and ecosystems. It provides a framework for identifying and categorizing the level of threat faced by different species.

K-selected species

: K-selected species are organisms that have low reproductive rates, produce fewer offspring, and have longer lifespans. They typically inhabit stable environments where resources are consistently available.

Lacey Act

: The Lacey Act is a United States law that prohibits the trade of illegally sourced plants and wildlife. It makes it illegal to import, export, transport, sell, or purchase any plant or animal species taken in violation of U.S. or foreign laws.

Near threatened (NT)

: Near threatened is a category used by the International Union for Conservation of Nature (IUCN) to classify species that are at risk of becoming endangered in the near future. These species may have declining populations or face specific threats to their survival.

Overharvesting

: Overharvesting refers to the excessive removal or exploitation of natural resources beyond their sustainable limits, leading to depletion or extinction.

Probability of extinction

: The probability of extinction refers to the likelihood that a species will become extinct in a given time period due to various factors such as habitat loss, climate change, or competition.

Protected areas

: Protected areas are designated regions of land or water that are managed and conserved to preserve their natural, cultural, or historical significance. They serve as sanctuaries for biodiversity and provide habitats for various species.

r-selected species

: r-selected species are organisms that have a high reproductive rate and produce many offspring, but provide little parental care. They typically have short lifespans and reach sexual maturity quickly.

Specialist species

: Specialist species are organisms that have specific requirements and can only survive in a narrow range of environmental conditions or by consuming specific types of food.

9.9 Endangered Species

7 min readjanuary 15, 2023

Jenni MacLean

Jenni MacLean

Riya Patel

Riya Patel

Jenni MacLean

Jenni MacLean

Riya Patel

Riya Patel

Classification

Any organism including plants or animals can become endangered. Organisms are classified by the International Union for Conservation of Nature (IUCN) into the following categories. 

https://upload.wikimedia.org/wikipedia/commons/thumb/0/00/Schematic_of_categories_to_classify_ecosystems_according_to_the_IUCN_Red_List_of_Ecosystems_criteria.png/1280px-Schematic_of_categories_to_classify_ecosystems_according_to_the_IUCN_Red_List_of_Ecosystems_criteria.png

Image Courtesy of Wikimedia

Extinct (EX) – These species no longer exist and have become extinct.

Extinct in the wild (EW) – Survives only in captivity, cultivation and/or outside the native range, as presumed after exhaustive surveys.

Critically endangered (CR) – These species are at an extremely high risk of extinction in the wild and their population is declining at an alarming rate.

Endangered (EN) – These species are at a very high risk of extinction in the wild and their population is declining rapidly.

Vulnerable (VU) – Meets one of the 5 red list criteria and thus considered to be at high risk of unnatural (human-caused) extinction without further human intervention.

Near threatened (NT) – These species are at risk of becoming endangered in the near future.

Least concern (LC) – These species are considered to have a low risk of extinction and are not considered endangered.

Conservation Status Classification

IUCN uses five criteria to classify organisms and assess their . The of a species refers to its risk of extinction in the wild. These criteria are:

A) Reduction in population: The population size of the species has decreased significantly over a certain period of time.

B) Geographic range: The species has a restricted geographic range or habitat.

C) Population size: The species has a small population size, estimated to number fewer than 2,500 mature individuals, and is in decline.

D) Extremely small population size: The species has an extremely small population size, estimated to number fewer than 250 mature individuals.

E) : A quantitative analysis has shown that the probability of the species becoming extinct in the wild is at least 20% within 20 years or five generations.

These criteria are used to classify species into the different categories of the IUCN Red List, such as Least Concern, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, and Extinct. The criteria are intended to provide a consistent and objective way to assess the of a species, and to help prioritize conservation efforts.

Check out https://www.iucnredlist.org to look at the population status of thousands of plants and animals.

Risk Factors

Certain organisms are inherently more at risk for extinction than others due to their biology and ecology. The difference in reproductive rate, as well as the ability of an organism to adapt to environmental change, are two key factors that can influence the survival and extinction risk of a species.

, such as mice, have a high reproductive rate and can quickly rebound from population losses. These species are typically short-lived and have many offspring that have a low chance of survival.

, such as elephants, have a lower reproductive rate and take longer to recover from population losses. These species are typically long-lived and have fewer offspring that have a higher chance of survival.

, such as orangutans, have a very specific niche and are adapted to a particular set of conditions. They can be particularly vulnerable to environmental changes and pressures, such as habitat loss, as they may not be able to adapt to new conditions.

, such as pigeons, are able to adapt to a variety of different climates, food sources, and environmental challenges. They tend to be more resilient to environmental changes and pressures, but they can also compete with native species and alter the ecosystem.

Overharvesting

Hunting, fishing, and other forms of harvesting are the most direct human influences on wild populations of plants and animals. occurs when individuals are removed from a population at a rate faster than the population can replace them. This can lead to population declines and even extinction, as seen in the case of the dodo bird on Mauritius.

Historically, market hunting has led to the of many species, such as the American bison and passenger pigeon, causing dramatic declines in population numbers. However, with the implementation of regulations and legal protections, many species have been able to recover, such as the American bison.

Regulations such as hunting and fishing restrictions and limits on the number of animals that can be harvested have been implemented in many countries to prevent . However, in some regions of the world, harvest regulations are not enforced, and continues to threaten species with extinction.

Illegal harvesting of rare animals, such as tigers, rhinoceroses, and apes, and rare plants, birds, and coral reef dwellers for private collections has become an increasing problem, and it's threatened the persistence of these species.

Plant/Animal Trade

The trade in plants and animals can represent a serious threat to the persistence of some species. Laws such as the in the United States and the United Nations Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) were developed to control and regulate the trade of threatened and endangered plants and animals.

The , first passed in 1900, originally prohibited the transport of illegally harvested game animals across state lines. Today, the Act prohibits the interstate shipping of all illegally harvested plants and animals. CITES is an international agreement among 182 countries worldwide, which aims to control the international trade of threatened and endangered species.

Despite these laws and agreements, illegal trade in plants and animals continues to occur worldwide. Illegal trade in wildlife is estimated to be worth between 5 billion to 220 billion dollars annually. Illegal trade in wildlife and wildlife parts have been sent to United States ports over a 10-year period. The illegal trade in wildlife is driven by demand for fur, body parts thought to have medicinal value, and rare animals as pets.

Even legal trade in certain species can pose a potential long-term threat to species persistence. In the southwestern United States, for example, the growing movement to reduce water used by replacing grass lawns with desert landscapes has led to an increased demand for cacti and other desert plants collected from the wild, causing concern for these plant populations in the wild.

Conservation

Countries have implemented a variety of strategies to address the decline in species and protect endangered and threatened species. One of the most important strategies is the implementation of legislation to protect habitats. The Endangered Species Act of 1973 in the United States, for example, aims to protect endangered and threatened species by preserving habitats from development.

Endangered Species Act

The Endangered Species Act (ESA) of 1973 is a federal law in the United States that aims to protect and recover species that are in danger of extinction throughout all or a significant portion of their range. The Act is administered by the U.S. Fish and Wildlife Service (FWS) and the National Oceanic and Atmospheric Administration (NOAA) and it is one of the strongest laws in the world for protecting endangered and threatened species.

The ESA provides for the listing of species as either "endangered" or "threatened" based on their risk of extinction. Once a species is listed, the Act requires the federal government to take actions to protect and recover it. This includes the designation of "critical habitat," which is defined as specific areas that are essential for the conservation of the species, as well as the prohibition of harming the listed species and their trade, including their fur or body parts.

The Act also implements the international CITES agreement, which regulates the trade of threatened and endangered species. To assist in the conservation of threatened and endangered species, the Act authorizes the government to purchase habitat that is critical to the conservation of the species and to develop recovery plans to increase the population of threatened and endangered species.

The ESA has been the center of much debate and controversy in recent years, as it can restrict certain human activities in areas where listed species live, including how landowners use their land. Despite this, the Act has had significant success in protecting and recovering endangered and threatened species, with several species being removed from the list as their populations have increased. However, efforts to weaken the ESA have been ongoing and it's important to continue to support and advocate for its protection.

Education

Another key strategy is education, raising public awareness about the potential extinction of species and the impact of human actions on biodiversity. Through education, people can learn about the importance of conservation and take steps to support it.

Breeding Programs

Captive breeding programs in zoos and aquariums can also play a role in species conservation. These institutions can serve as education centers, while at the same time using the animals in captive breeding programs to rebuild populations of critically endangered species. Programs like the Smithsonian National Zoo and the San Diego Zoo have been instrumental in establishing populations of species like the black-footed ferret, red panda, and clouded leopard.

Organizations

In addition, conservation organizations, non-governmental organizations, and research institutions have been working in collaboration with governments to address the decline in species, through research, monitoring, and conservation actions in the field, and also by creating , corridors, and reintroduction programs.

Key Terms to Review (17)

Conservation status

: The conservation status refers to the assessment of how threatened a species is with extinction. It takes into account factors such as population size, geographic range, and habitat quality.

Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

: CITES is an international agreement between governments aimed at ensuring that international trade does not threaten the survival of wild animals and plants. It regulates the trade of certain species by listing them under different appendices based on their level of protection.

Critically endangered (CR)

: Critically endangered is the highest risk category assigned to species that are facing an extremely high risk of extinction in the wild. These species have very small populations or are experiencing a rapid decline in their population size.

Endangered Species Act (ESA)

: The Endangered Species Act (ESA) is a law in the United States that aims to protect and recover endangered and threatened species and their habitats. It provides legal protection for these species, prohibits activities that harm them or their habitats, and promotes conservation efforts.

Extinct (EX)

: Extinct refers to a species that no longer exists anywhere on Earth. It means there are no living individuals left, and the species has completely disappeared from the planet.

Extinct in the wild (EW)

: Extinct in the wild refers to a species that no longer exists naturally in its native habitat but continues to survive only through captive breeding programs or reintroduction efforts.

Generalist species

: Generalist species are organisms that can adapt and thrive in a wide range of environmental conditions and can consume various types of food.

Illegal poaching

: Illegal poaching refers to the illegal hunting, capturing, or killing of wildlife, usually for commercial purposes. It involves the exploitation of protected species and can have severe ecological consequences.

International Union for Conservation of Nature (IUCN)

: The International Union for Conservation of Nature (IUCN) is an international organization that assesses the conservation status of species and ecosystems. It provides a framework for identifying and categorizing the level of threat faced by different species.

K-selected species

: K-selected species are organisms that have low reproductive rates, produce fewer offspring, and have longer lifespans. They typically inhabit stable environments where resources are consistently available.

Lacey Act

: The Lacey Act is a United States law that prohibits the trade of illegally sourced plants and wildlife. It makes it illegal to import, export, transport, sell, or purchase any plant or animal species taken in violation of U.S. or foreign laws.

Near threatened (NT)

: Near threatened is a category used by the International Union for Conservation of Nature (IUCN) to classify species that are at risk of becoming endangered in the near future. These species may have declining populations or face specific threats to their survival.

Overharvesting

: Overharvesting refers to the excessive removal or exploitation of natural resources beyond their sustainable limits, leading to depletion or extinction.

Probability of extinction

: The probability of extinction refers to the likelihood that a species will become extinct in a given time period due to various factors such as habitat loss, climate change, or competition.

Protected areas

: Protected areas are designated regions of land or water that are managed and conserved to preserve their natural, cultural, or historical significance. They serve as sanctuaries for biodiversity and provide habitats for various species.

r-selected species

: r-selected species are organisms that have a high reproductive rate and produce many offspring, but provide little parental care. They typically have short lifespans and reach sexual maturity quickly.

Specialist species

: Specialist species are organisms that have specific requirements and can only survive in a narrow range of environmental conditions or by consuming specific types of food.


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AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.


© 2024 Fiveable Inc. All rights reserved.

AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.