Ecosystem

The term “forest” is extremely broad. In its broadest definition, a forest is an area primarily covered in trees and undergrowth. There are many different types of forests categorized by the surrounding climate: tropical, temperate, and alpine.

Further categorization includes describing the dominant type of trees, for example, dry evergreen, pine forest, and moist deciduous. 

This forest is classified as an American Northeast deciduous forest. Deciduous forests will usually contain different fauna and undergrowth flora than those that are found in evergreen forests. 

The nonliving parts of an ecosystem are called abiotic components. In this ecosystem it includes the river, the specific types of rocks and minerals which make up the soil, the amount of rainfall, the climate, and even the air composition.

The rocks and minerals which form the soil will help determine what species of plants will grow there. This in turn determines what species of animals will inhabit the ecosystem.

The amount of rainfall, the balance of salt water vs. fresh water, whether frost or snow occurs, and the water table height also play a large role in determining what species of plants and animals will occupy the ecosystem.

The living components directly interact with the abiotic components in an ecosystem. A long–term change in any of the abiotic components will directly affect the living components. 

Critical to the broader natural environment, water covers the soil or is near the soil’s surface in wetlands areas almost all year–round.

These important ecosystems play a large role in filtering water pollution, protecting shorelines from wave action, reducing the impact of floods, and providing an important nursery site and habitat for many animals. 

In all ecosystems, the producers are the “base” level of life. Producers are living organisms capable of converting energy from sunlight into sugars used for growth and reproduction. 

Plants, algae, and photosynthetic bacteria are producers, making food for the consumers such as fish, birds, and amphibians. By weight, producers make up the bulk of the ecosystem.

Producers act as an interface with the ecosystem’s abiotic components. Plants draw nutrients from the soil and energy from the sun to create food sources. They also remove carbon dioxide from the atmosphere.

Found in the Earth’s far Northern Hemisphere, one of the major features of the tundra ecosystem is its permanently frozen ground. It’s also mostly treeless. Despite these harsh and difficult conditions, a wide variety of life inhabits this type of ecosystem.

Consumers are living organisms who obtain their energy by eating producers and/or other consumers. Primary consumers eat producers like plants and then secondary consumers eat the primary consumers.

We classify consumers into 3 types. Herbivores are animals that only eat plant material. They have evolved a wide range of specialized features to help them break down tough plant cells.

Carnivores only eat other animals. These animals have evolved a different set of features that allow them to tear flesh and digest meat. Some carnivores, like cats, cannot digest plants correctly.

Omnivores are animals that consume both plant matter and other animals. These types of animals have evolved both herbivore features and carnivore features. Did you know that ants may be the smallest omnivores of all?

When considering the flow of nutrients within an ecosystem we see that the ultimate energy producer is our sun. Producers receive their energy from the sun, and then pass on this energy to consumers. 

Marine ecosystems, the largest ecosystems on Earth, cover about 70% of the planet’s surface. They can be classified into categories such as estuaries, deep sea, tropical, sea floor, and coral reefs. The common link between them all is the presence of salt water. 

Although often small and rarely seen, decomposers are critical within ecosystems. These organisms break down waste material created by producers and consumers, as well as dead organisms. 

Organisms such as sea stars, sea slugs, and some types of bacteria are responsible for breaking down organic matter within the marine ecosystem. Some of these decomposers, such as sea urchins, are also consumers.

Decomposers return nutrients to abiotic components, particularly within the soil. Producers can then use those nutrients in the soil and create food for consumers, and continue the ecosystem’s food chain. 

Ecosystems aren’t static. Over time factors such as climate change, invasive species, human interaction, and a change in atmospheric carbon levels can transform an ecosystem completely.

The speed at which these factors occur determines whether a new ecosystem will develop, or whether the area essentially loses life entirely. 

Many types of plants and animals have evolved to survive desert conditions. The key to a species survival in any ecosystem is slow, gradual change over millions of years.

Parts of the Sonoran desert in the U.S. were formed during volcanic activity which created the mountains surrounding the area. These mountains captured the rain, leaving the basin dry. Over a very long time the area became a desert. 

The Sonoran desert has a huge range of species that have adapted to the harsh conditions. This includes more than 60 species of mammals, 350 species of birds, and 100 species of reptiles.

Although the Sahara desert, the largest desert in the world, hosts a large array of desert–adapted species, it is also the site of a recent mass extinction. 

The Sahara expanded rapidly 12,000 years ago. Previously it contained grasslands and large forests with numerous freshwater lakes. When rapid desertification occurred, species living in the region had no time to evolve adaptations and disappeared.

Before 10,000 years ago, humans left little impact on the Earth’s ecosystems (although this theory is challenged when megafauna extinctions are studied).

The introduction of agriculture rapidly changed ecosystems around the world both with the development of monocultures (large areas of only one species like corn) and the advent of permanent settlements. Some animal and plant species have benefited greatly with these changes leading to the urban ecosystem.

Even human–built areas have the 4 components of ecosystems. Abiotic components, producers, consumers, and decomposers are all present within these areas. Urban ecosystems exist on all the continents.

Urban ecosystems have the same abiotic components as natural ecosystems: rainfall, climate, and soil profiles. Water is also present in stormwater and sewage systems, and tall buildings can create their own wind profiles.

Producers tend to be controlled by humans within an urban ecosystem. However, “weeds” are wild plant species that have decided to make the urban ecosystem their home (even if they were originally introduced to the region by humans).

Consumers within an urban ecosystem include birds, mammals, reptiles, and even fish. Consumers like the house sparrow have benefited enormously with human urbanization. This once unassuming species is now found throughout the world.

Although not as readily seen, the urban ecosystem contains a wide variety of decomposers. Snails, insects, worms, and bacteria all help break down natural material and return nutrients to the soil.

It’s easy to see ecosystems on a large scale. All around us, however, are microecosystems, entire biomes existing as ecosystems at a very small scale.

These microecosystems contain the same 4 components as large–scale ecosystems, and they play a role in the larger ecosystem as well.

This is a single drop of seawater magnified 25 times. However, note that in the ocean you wouldn’t find these organisms so close together.

Very small changes in abiotic components can greatly affect a microecosystem. A small change in temperature, pH levels, or amount of sunlight can have large consequences for tiny living organisms.

Phytoplankton form the basis of this ecosystem. These tiny organisms transform sunlight into sugars via photosynthesis. Phytoplankton play an important role in the larger marine ecosystem too, primarily as food for larger animals such as whales and fish. 

Consumers in this microecosystem include zooplankton. These tiny organisms eat phytoplankton, crab larvae, fish fry, and miniature shrimp. Larger consumers will then eat the zooplankton.

Many different types of bacteria act as decomposers at this level. They’re often the first decomposers to begin working on turning waste matter or dead material into nutrients for producers.