Biodiversity

Biodiversity is the variety of life on Earth. It means the many different kinds of plants, animals, fungi, and other living things. It also includes how they live together in groups called ecosystems. We can see this variety in genes, in the number of different species, and in the kinds of ecosystems.

The world is not the same everywhere for living things. Places near the equator, called the tropics, have the most variety. This is because they are warm and have lots of food for living things to grow. Tropical forests cover a small part of the land but hold about half of all the world's species.

Life on Earth has changed over time. There have been times when many species suddenly disappeared. These are called mass extinctions. One big change happened during the Cambrian explosion, when many new kinds of animals first appeared. Later, there were big losses too, like the Permian–Triassic extinction.

Today, human actions are causing many plants and animals to disappear. This is called the sixth mass extinction. Cutting down forests for farms and changes in the climate are big reasons why species are being lost. Scientists worry that many species could disappear by the year 2050 if these problems continue.

Definitions

Biologists usually describe biodiversity as all the different genes, species, and ecosystems in a place. This helps us see the many kinds of life together. Biodiversity can mean the variety of species, the different ecosystems, or the many ways living things can look and act.

People sometimes use "biodiversity" instead of simpler words like "species diversity" or "species richness." But there isn’t just one way to define it. Different groups may describe it a little differently, but they all talk about the many forms of life on Earth.

Number of species

Main article: Global biodiversity

Scientists think there are about 8.7 million species on land and 2.2 million in the ocean. These numbers are just guesses, especially for very small organisms. Other guesses include:

• 220,000 vascular plants
• 0.7–1 million marine species
• 10–30 million insects
• 5–10 million bacteria
• 1.5-3 million fungi
• 1 million mites

We do not really know how many tiny organisms, like microbes, exist. But studies of ocean water have found many new genes.

Birds and mammals are the most studied animals, while fish and arthropods are studied less.

Current biodiversity loss

We have seen a big drop in the variety of life on Earth over the past century. Many animals and plants are at risk.

The loss of different kinds of animals and plants is happening faster than ever before. This loss is caused mainly by human actions, like destroying places where animals and plants live.

Biodiversity helps keep our planet healthy. Scientists say that if we continue to lose it, it could threaten our own future as well.

Distribution

Biodiversity is not spread evenly around the world. It changes a lot depending on where you are, like the temperature, rain, height above sea level, and the types of soil. The places where there is the most life are usually warm and rainy, especially near the equator. For example, rain forests such as Yasuní National Park in Ecuador have lots of different plants and animals.

Biodiversity is very important for our daily lives. It helps us have clean water, different foods, and materials for energy. Forests are especially important because they are home to most of the world’s land animals and plants. However, problems like pollution, using too many resources, and changes in climate can harm biodiversity around the world.

Latitudinal gradients

Main article: Latitudinal gradients in species diversity

Generally, there are more types of plants and animals near the equator than near the poles. This pattern is called the latitudinal gradient in species diversity. Scientists think this happens because it is warmer near the equator, which helps more species to live there.

Biodiversity Hotspots

A biodiversity hotspot is a place with many special plants and animals that are found only there, but which are also in danger because their homes are being destroyed. These hotspots are often forests, and many are located in warm areas near the equator. Countries like Brazil, Madagascar, India, and Colombia have many hotspots. These special places need protection to save the unique life they support.

Evolution over geologic timeframes

Main article: Evolution

Biodiversity has grown over 3.5 billion years through evolution. Early life was simple, with tiny organisms like bacteria. Around 540 million years ago, many new animals appeared quickly in a time called the Cambrian explosion.

Even with these bursts of growth, there have been times when many species disappeared suddenly. One famous example is when the dinosaurs went extinct about 66 million years ago. Despite these losses, life kept growing and changing. Today, scientists think Earth may have up to one trillion species, but we’ve only found a small part of them. Most living things are found in tropical forests, and land usually has more species than the oceans.

Role and benefits of biodiversity

Ecosystem services

Further information: Ecosystem services and Ecological effects of biodiversity

Biodiversity helps the environment in many important ways. It gives us food, wood, and clean water. It also helps control the climate and protect us from pests and diseases.

There are three main types of these services:

1. Providing services like food, wood, and water.
2. Regulating services that help control the environment, such as managing the climate and stopping pests.
3. Cultural services that give us beauty, heritage, and places to enjoy the outdoors.

Experiments show that it is hard for humans to create ecosystems that work as well as natural ones. For example, machines cannot replace insects that pollinate plants, which is very important for growing food. The work of pollination alone is worth a lot of money each year.

Provisioning services

Having more kinds of plants can help us get more food and wood. Different types of plants can increase how much food we grow and how much wood we produce.

Regulating services

Biodiversity helps keep ecosystems strong and able to deal with changes. Different plants and animals can work together to help each other, which keeps the environment balanced. This can help protect against diseases and climate changes.

Agriculture

Main article: Agricultural biodiversity

Farming can include many different kinds of plants and animals. Some are planned, like the crops farmers grow, while others come naturally, like helpful insects that pollinate plants or pests that can cause problems.

Even though most of our food comes from just a few types of plants, many more species are used in different ways. Biodiversity gives us many options for food and other products.

Human health

Biodiversity is important for our health. It affects what we eat, helps prevent diseases, and provides materials for medicines. Many medicines come from plants, animals, and tiny organisms. Different kinds of ecosystems, like wetlands, also help protect communities from flooding and other natural events.

Business and industry

Further information: Economics of biodiversity

Biodiversity helps the economy by providing resources worth a lot of money each year. It supports businesses by keeping ecosystems healthy, which helps with things like clean water and stable climates.

Cultural and aesthetic value

Biodiversity also has value because it is beautiful and important to many cultures. It gives us places to learn, grow, and find meaning.

Measuring biodiversity

Most animals and plants have not been studied much. Many tiny organisms on Earth are very diverse and live in many places. Scientists often study larger animals and plants, but there is even more variety in the tiny creatures we don’t always see. Some animals, like insects, are at risk of disappearing, which worries scientists who study life on our planet.

Biodiversity changes (other than losses)

Natural seasonal variations

Biodiversity naturally changes with the seasons. In spring, many animals have babies and plants grow, which adds to diversity. In winter, some insects die and animals move away, which can lower diversity for a short time.

Introduced and invasive species

Main articles: Introduced species and Invasive species

Barriers like rivers, seas, oceans, mountains, and deserts help create diversity by letting species develop separately on each side. Sometimes, species cross these barriers and become invasive. These species can take over areas meant for native species.

Humans often move species from one place to another, either on purpose or by accident. This can lead to invasive species taking over new areas. Invasive species often reduce the variety of native species.

Hybridization and genetic pollution

Endemic species can be threatened when they mix with other species through uncontrolled hybridization. This mixing can weaken rare species by blending their genes with more common species, making it hard for the rare species to survive.

Conservation

Main article: Conservation biology

Conservation biology began in the middle of the 1900s when scientists started studying ways to help protect plants and animals.

The idea of conservation is to take care of nature’s resources. This helps keep different plants and animals, their homes, and how they change safe for both nature and people.

Conservation plans now work to protect all forms of life. They try to help people, their communities, and nature at local, regional, and global levels. These plans show people how to live well while using nature carefully. In some places, zoos help protect animals by doing research and special breeding programs.

Protected areas

Further information: Protected areas

Protected areas, like forest reserves and special nature areas, help keep wild animals and plants safe. These areas are set up all around the world to protect nature. Some scientists suggest protecting 30% of Earth by 2030 and 50% by 2050 to help save many plants and animals. In 2022, almost 200 countries agreed to protect 30% of Earth by 2030.

Protected areas help nature and also support people, especially in local communities. There are over 238,000 protected areas covering about 15% of Earth’s land. These areas give many benefits, like clean water, medicines, and places for people to enjoy nature.

National parks and wildlife sanctuaries

Main articles: National park and Wildlife sanctuaries

A national park is a big natural area where governments or groups work to protect plants, animals, and natural processes. These parks also aim to teach people about nature and give chances for visitors to enjoy the outdoors. Wildlife sanctuaries are special places that help animals which cannot live on their own, or give animals a safe place to get healthier.

Both national parks and wildlife sanctuaries help keep biodiversity safe. They work to keep ecosystems healthy and teach the public about wildlife.

Forest protected areas

Forest protected areas are parts of forests set aside to keep them safe. About 18% of the world’s forests are inside protected areas like national parks. Forests are home to many plants and animals, including some that live only in certain places.

In forest reserves, people living near forests may be allowed to do some activities, like hunting or grazing, which help them live. In Europe, about 24% of forest land is protected to help nature and the landscape.

Role of society

In 2019, a big report about nature was shared with leaders. It said nature is changing quickly, and we need to help protect it. This means better farming, using fewer things, and working together to manage water.

People can help scientists learn more about nature by sharing what they see. Many people help collect information about plants and animals. Websites like iNaturalist and eBird make it easy for everyone to share their observations.

Legal status

Global agreements help protect plants, animals, and natural areas. These agreements ask countries to care for their natural resources, share benefits fairly, and work together to protect the environment. In 2022, almost every country agreed to protect 30% of land and oceans by 2030, along with other goals to stop the loss of nature.

The European Union has its own plan to protect nature by 2030. This includes protecting parts of the sea and land, planting billions of trees, and reducing harmful chemicals used in farming. Many jobs and money in Europe depend on healthy nature.

History of the term

The idea of biodiversity began in the early 1900s. In 1916, a scientist named J. Arthur Harris talked about "biological diversity" in Scientific American. Later, in 1967, Raymond F. Dasmann used the same term in a book about nature protection.

More scientists started using the term. By 1980, Thomas Lovejoy helped make "biological diversity" well-known in science. In 1986, the shorter word "biodiversity" was created. Since 1988, the United Nations has worked to protect biodiversity with meetings around the world. The most recent meeting was in Cali, Colombia, in 2024.