Biodiversity

Earth is full of many living things.

This variety is called biodiversity. Some places have more life than others. Warm lands near the middle of Earth have many kinds of life.

Tropical forests have many species. But some life is being lost today. People use land for farms. This takes homes away from animals.

We must learn how to help them.

Biodiversity is the variety of life on Earth.

It includes many different parts. We can look at genes. We can look at species. We can also look at ecosystems. An ecosystem is a group of living things in one area.

Life is not spread out the same way everywhere. There is more life in the tropics. These are warm areas near the equator. Tropical forests cover a small part of Earth. Yet, they hold about half of all species.

Long ago, Earth had mass extinctions. These were times when many species died out fast. Today, we see a new loss of life. This is often called the sixth mass extinction. Human activities cause this loss. People destroy habitats to make room for farms. Climate change also helps cause this loss. Some studies say up to 30% of species will be gone by 2050.

We must understand these changes to help our planet.

Biodiversity is the wonderful variety of life found on our planet.

It is not just a list of different animals. Scientists look at it on many different levels. They study genetic variability, which is the variety within a single group. They also look at species diversity and ecosystem diversity. Some even study phylogenetic diversity, which looks at the different branches of the tree of life.

This variety is what makes our world so complex and interesting. It helps nature stay strong and adapt to changes.

Life is not spread out evenly across the globe.

You will find much more variety in the tropics. These are the warm areas near the equator. In these regions, high primary productivity helps many things grow. Tropical forest ecosystems cover less than one-fifth of the land. Yet, they hold about 50% of all the world's species.

This means a tiny part of the Earth holds half of its life. Other areas, like the polar regions, have much less variety.

Earth has a long history of changing life.

The last 540 million years are called the Phanerozoic aeon. During the Cambrian explosion, many different types of life appeared quickly. However, there were also six major mass extinctions. These were times when many species died out very suddenly. One huge event happened 251 million years ago. It was the Permian–Triassic extinction event. It was the worst one ever recorded. It took 30 million years for animals to recover.

Today, we are seeing a new kind of loss.

Some call this the Holocene extinction or the sixth mass extinction. This is happening because of human activities. People often destroy habitats to make room for farming.

Climate change is also a big reason for this loss. Some estimates say up to 30% of all species could be extinct by 2050. The rate of loss today is much faster than in the past.

We can see how this affects everything we know.

Biodiversity provides many things that humans need to live. It helps provide fresh water and different food choices. It even helps give us fuel sources. When we lose variety, we lose the natural tools that keep the planet healthy. Studying these patterns helps us understand our own place in nature. Protecting these many different living things is a very important job.

Biodiversity refers to the total variety of life found on Earth.

It is a complex concept that scientists study at several different levels. Biologists often define it as the totality of genes, species, and ecosystems within a specific region. This definition allows for a unified view of biological variety. It includes taxonomic diversity, which is usually measured by looking at different species. It also includes ecological diversity, which focuses on different ecosystems. Furthermore, morphological diversity stems from genetic and molecular diversity. Finally, functional diversity measures the number of species with different roles, such as different feeding mechanisms or movement styles.

Life is not spread out evenly across our planet.

Instead, there are clear latitudinal gradients in species diversity for both land and sea creatures. Diversity is generally much higher in the tropics due to the warm climate. High primary productivity in regions near the equator also supports more life. While tropical forest ecosystems cover less than one-fifth of Earth's land area, they contain about 50% of the world's species.

Other areas, such as the polar regions, show much lower levels of diversity. The study of how these organisms are distributed is called biogeography.

Estimating the exact number of species on Earth is a massive challenge.

Some researchers estimate there are about 8.7 million terrestrial species and 2.2 million oceanic species. These numbers are considered strong estimates for eukaryotic organisms. Other estimates provide different figures for specific groups. For example, there may be 10 to 30 million insects, but we only know of about 0.9 million today. Estimates for fungi range from 1.5 to 3 million species. The number of microbial species is not yet reliably known, but the Global Ocean Sampling Expedition found many new genes in marine plankton. This discovery may change how scientists define species in the future.

Earth's history is marked by both rapid growth and sudden loss.

The Phanerozoic aeon covers the last 540 million years of life. This period saw a rapid increase in biodiversity during the Cambrian explosion. During this time, most multicellular phyla first appeared. However, the next 400 million years included repeated, massive biodiversity losses known as mass extinction events. One major event occurred during the Carboniferous when a rainforest collapse may have caused huge losses. The worst event was the Permian–Triassic extinction 251 million years ago. It took 30 million years for vertebrate life to recover from that disaster.

Today, the planet is experiencing a new period of rapid loss.

This is often called the Holocene extinction or the sixth mass extinction. Human activities are the primary drivers of this ongoing decline. Habitat destruction for farming is a key reason why biodiversity is decreasing. Climate change also plays a significant role by impacting various biomes. Some studies suggest human-driven extinction may have even started near the end of the Pleistocene. This was linked to the overhunting of megafauna at the end of the last ice age.

Recent data shows how quickly wildlife populations are changing.

The World Wildlife Fund reported that wildlife populations declined by an average of 73% since 1970. In terms of absolute numbers, the planet has lost 58% of its biodiversity since that same year. In 2007, researchers estimated that up to 30% of all species could be extinct by 2050. Some studies suggest that 25% of all mammal species could be extinct within 20 years. In Germany, the biomass of insect life fell by three-quarters in just 25 years. These rates are hundreds of times higher than the natural background extinction rates seen in the fossil record.

This loss of variety has serious consequences for the entire planet. Biodiversity provides essential natural capital that supplies ecosystem goods and services. It affects the availability of fresh water, food choices, and fuel sources for humans. The decline also destroys the resilience and adaptability of life on Earth. When ecosystems lose species, they lose their ability to handle changes. This decline is considered a critical part of the Anthropocene, the current era of human impact. Protecting the variety of life is necessary to maintain the systems that support human civilization.