Animals walk, crawl, and slither over most of Earth, and plants thrive in places ranging from prairies to the bottoms of ponds. This abundance of life is possible because of many abiotic factors, which are the nonliving physical and chemical aspects of an ecosystem.

Abiotic factors are a bit like the Little Bear's porridge in the Goldilocks' story—they have to be just right in order for life to flourish. Many animals also require a particular set of abiotic factors to thrive. Imagine a snake living in the Arizona desert. It is right at home in that dry landscape because it is able to move through loose soil and sand by twisting its body. It can also avoid the heat by hiding under rocks. Some snakes are also nocturnal—that is, they hunt and move around mostly during the night when the sun is not shining. Now imagine that someone picks up one of these desert-adapted snakes and places it on a snowy peak in the Himalayas. The Himalayas lack the abiotic factors—like an arid climate and loose soil—that the snake is adapted to, and the snake likely will not be able to survive.

Humans, like other animals, also require certain abiotic factors to survive and live comfortably. For starters, we need oxygen to breathe—respiration powers our cells. We live on a planet that is shielded from the ultraviolet radiation of the sun; the cells in our bodies are susceptible to damage from ultraviolet light. Ultraviolet radiation can cause genetic damage and even trigger cancer. Earth’s thick atmosphere acts as a shield against ultraviolet radiation.

As ecosystems change over time, abiotic factors can also vary. For instance, the pH of water is changing in some parts of the ocean as carbon dioxide dissolves in the water, making it more acidic. There has been a 30 percent increase in the acidity of some regions of the ocean since the Industrial Revolution. Some creatures, such as corals, are unable to adapt to this increased acidity, and coral reefs suffer as a result. Other animals, such as marine snails, are also hurt by acidic waters—their protective shells literally dissolve.

Humans have also learned how to intentionally alter the abiotic factors of the environment. For instance, every time you turn on the air conditioning or sprinkle salt on a road to help snow melt, you are changing abiotic factors.