The Great Oxygenation Event was a major increase in atmospheric oxygen levels that occurred approximately 2.4 billion years ago. It is not considered an extinction event as it did not lead to a significant loss of biodiversity.

Living fossils are organisms that have survived largely unchanged for millions of years. Examples of living fossils include the tuatara, a reptile that has been around for over 200 million years, the coelacanth, a fish that was thought to be extinct until it was rediscovered in 1938, and Ginkgo biloba, a tree that has been around for over 200 million years.

Evolution is the process by which species adapt to their environment over time. It occurs through natural selection, which is the process by which organisms with traits that are better suited to their environment are more likely to survive and reproduce.

Keystone species are species that have a disproportionately large impact on their ecosystem relative to their abundance. Examples of keystone species include the sea otter, which helps to control populations of sea urchins and kelp forests, the African elephant, which helps to maintain savanna ecosystems, and the monarch butterfly, which plays a vital role in pollination.

Overexploitation is the process by which humans have caused a significant reduction in the population size of a species. This can occur through hunting, fishing, or other forms of resource extraction.

The California condor, the black-footed ferret, and the giant panda are all examples of conservation success stories. These species were all once on the brink of extinction, but thanks to conservation efforts, their populations have rebounded.

Rewilding, restoration ecology, and ecological restoration are all terms used to describe the process by which humans restore degraded ecosystems to their natural state. This can involve planting native trees and shrubs, removing invasive species, and reintroducing native wildlife.

Protected areas are areas of land or sea that are designated for conservation purposes. This can include national parks, wildlife sanctuaries, and marine protected areas.

Sustainability is the process by which humans reduce their impact on the environment. This can involve using renewable energy sources, reducing consumption, and recycling and composting.

Sustainable practices are those that reduce our impact on the environment. Examples of sustainable practices include using renewable energy sources, reducing consumption, and recycling and composting.

Environmental education, conservation education, and sustainability education are all terms used to describe the process by which humans educate themselves and others about environmental issues.

Environmental education programs are those that teach people about environmental issues. Examples of environmental education programs include school field trips to natural areas, nature documentaries, and environmental science classes.

Environmental activism, conservation activism, and sustainability activism are all terms used to describe the process by which humans take action to protect the environment.

Environmental activists are people who take action to protect the environment. Examples of environmental activists include Greta Thunberg, David Attenborough, and Wangari Maathai.

Sustainable development is the process by which humans create a more sustainable future. This can involve using renewable energy sources, reducing consumption, and recycling and composting.