By Meg Deak
A puddle in your backyard, the amazon rainforest and the ground under a rock might seem like they have nothing in common. However, there is at least one similarity between these environments, they can all be classified as an ecosystem; areas where a community of organisms lives with their physical environment. Earth is made up of a series of connected ecosystems.
What’s in an Ecosystem?
Ecosystems encompass biotic (living), and abiotic (nonliving) components. Biotic components include organisms such as plants, animals, bacteria and fungi. Abiotic components include factors such as rock, temperature and humidity. They are organized generally based on the plants and animals that live in them.
Every factor in an ecosystem is interdependent. For example, a change in temperature can affect what plants can grow in that ecosystem. Animals which depend on specific plants for food will have to either adopt, move or perish when the types of plants in an ecosystem change.
Ecosystems also vary in size and can be marine, aquatic or terrestrial. Ocean ecosystems are Earth’s most common ecosystem, which makes sense considering oceans cover 75% of the planet’s surface. Freshwater ecosystems by contrast are the rarest ecosystem, covering 1.8% of Earth’s surface. Land (terrestrial) ecosystems cover the remaining area.
In an ecosystem a defining factor is that energy and matter are conserved. While energy flows through the ecosystem, from light to heat, matter is recycled.
Imagine you travel from the rainforest to the desert, then to a temperate forest or savannah. These ecosystems all encompass a large stretch of land, that will have characteristically different environments. This makes further categorization helpful.
Large stretches of land, sea, or atmosphere are categorized into biomes. Rain forests, coral reefs, savannas, deserts, deciduous forests, and tundra are all examples of Biomes. Biomes are different largely because of differences in location and climate.
More Than One Ecosystem
The idea that biomes are made up of one ecosystem alone is a common misconception. Biomes are complex and made up of multiple ecosystems.
For example, the Sahara Desert is a biome made up of oasis and dune ecosystems and a marine environment. Oasis ecosystems are characterized by date palm trees, freshwater, and crocodiles. In contrast, dune ecosystems have a sandy dune landscape which changes based on the wind. Classic organisms in these ecosystems include snakes and scorpions. These are both also very different from a marine environment.
Two biomes can also contain different ecosystems even though they sound similar. For example, the Sahara Desert is different than the Gobi desert in Mongolia China, which is a cold desert.
What Makes a Biome a Biome?
Since Biomes can have more than one ecosystem you may be asking yourself how you know when a biome ends and another one starts. The answer isn’t straightforward. Biomes have no distinct boundaries.
There are transitional zone ecosystems, called ecotones. Ecotones might contain plants and animals from two biomes.
Further, scientists disagree on what makes a biome a biome. However, one commonality across definitions is that biomes are distinct based on the organisms living there, with specific adaptations for the environment, and based on the climate.
Should humans be included in biome definitions? This is a question scientist are exploring. While some disagree, others point out our influence on biomes might make it essential.