Understanding Ecosystems: Habitats, Keystone Species, and Invasive Threats
Habitat
A habitat is the natural environment in which a living organism lives.
Keystone Species
A keystone species plays an important role in an ecosystem, maintaining biodiversity. Without keystone species, the ecosystem would be drastically different or cease to exist altogether.
Ecosystem
An ecosystem includes all organisms living in a certain area and the environment surrounding that area.
Types of Keystone Species
- Keystone Predators: Predators help control the populations of prey species, which in turn affects the quantity of plants and animals further along the food web.
- Keystone Modifiers/Ecosystem Engineers: An ecosystem engineer is any organism that creates, significantly modifies, maintains, or destroys a habitat. This allows new, healthier trees to grow in abundance.
- Keystone Mutualists: When two or more species in an ecosystem interact for each other’s benefit, they are called mutualists.
- Keystone Host: Plants and other producers.
Ecological Interactions
- Competition: The Double Negative. Competition exists when multiple organisms vie for the same limiting resource. Because the use of a limited resource by one species decreases availability to the other, competition lowers the fitness of both.
- Mutualism: Everyone Wins.
- Commensalism: A Positive/Zero Interaction.
- Parasitism: Good and Harm. One species benefits by obtaining resources from and to the detriment of the other.
Food Web
Food webs are big, tangled systems that include every plant and animal in a habitat. A food web shows different paths as an animal finds food.
10% Law
Primary consumers get 10% of the energy produced by autotrophs, secondary consumers get 1%, and tertiary consumers get 0.1%.
Energy Pyramids
A wide bottom and a drastic reduction as it goes up indicates a healthy ecosystem.
Biomass Pyramids
In a terrestrial ecosystem, a wide bottom means it is healthy, but in a marine ecosystem, a small bottom might also be healthy.
Number Pyramids
They can be upright, lumpy, or inverted depending on the system. They show the number of individual organisms.
Invasive Species
An invasive species can be any kind of living organism that is not native to an ecosystem and causes harm. They can harm the environment, the economy, or even human health. These species grow and reproduce quickly and spread aggressively, occupying unnatural niches. Invasive species are primarily spread by human activities, often unintentionally. People, and the goods we use, travel around the world very quickly, and they often carry uninvited species with them. Since an invasive species may not have any natural predators or controls, it can breed and spread quickly, taking over an area.
The direct threats of invasive species include:
- Preying on native species
- Outcompeting native species for food or other resources
- Causing or carrying disease
- Preventing native species from reproducing or killing a native species’ young
Endemic Species
Endemic species are plants and animals that exist only in one geographical region. Species can be endemic to large or small areas of the world. Some may be endemic to a particular continent, some to a part of a continent, and others to a single island. Endemic species are important because they are restricted to a particular area due to climate change, urban development, or other occurrences. Endemic species are often endangered, so it’s important to protect them.