What are the main causes of species extinction?

The main causes of species extinction are habitat destruction, overexploitation, pollution, climate change, and invasive species.

Habitat destruction is one of the leading causes of species extinction. This can occur through deforestation, urbanisation, or other forms of land-use change. When a species' habitat is destroyed or significantly altered, they may not be able to adapt to the new conditions and could die out. For example, many species of orangutans are critically endangered due to the destruction of their rainforest habitats for palm oil production.

Overexploitation is another significant cause of extinction. This refers to the unsustainable use of species for economic or recreational purposes. Overfishing, for instance, has led to the decline of many fish species worldwide. Similarly, illegal wildlife trade can lead to the extinction of species that are hunted for their body parts, such as elephants for their ivory or rhinos for their horns.

Pollution is a further cause of species extinction. This can include air, water, and soil pollution. Chemicals and waste materials released into the environment can harm species directly, or disrupt their habitats and food sources. For example, pesticides used in agriculture can contaminate water sources, affecting aquatic species and those that rely on them for food.

Climate change is increasingly recognised as a major driver of species extinction. Changes in temperature, precipitation patterns, and sea levels can alter habitats and disrupt ecosystems. Species that are unable to adapt to these changes may face extinction. For example, polar bears are threatened by the loss of sea ice due to global warming.

Lastly, invasive species can cause extinction by outcompeting native species for resources or by preying on them. Invasive species often have no natural predators in their new environments, allowing their populations to grow unchecked. For example, the introduction of the brown tree snake to Guam led to the extinction of several bird species on the island.

In conclusion, species extinction is a complex issue with multiple causes. It is often the result of human activities, highlighting the need for sustainable practices to protect biodiversity.