In the kelp forest, sea otters are secondary consumers that hunt sea urchins as prey. Tertiary consumer s eat the secondary consumers. They are at the fourth trophic level. In the desert ecosystem, an owl or eagle may prey on the snake. There may be more levels of consumers before a chain finally reaches its top predator. Top predators, also called apex predator s, eat other consumers. They may be at the fourth or fifth trophic level. They have no natural enemies except people.
- Chaos: A Very Short Introduction;
- Browse more videos!
- Insect Symbiosis.
Lions are apex predators in the grassland ecosystem. In the ocean, fish such as the great white shark are apex predators. In the desert, bobcats and mountain lions are top predators. Consumers can be carnivore s animals that eat other animals or omnivore s animals that eat both plants and animals.
Omnivores, like people, consume many types of foods. People eat plants, such as vegetable s and fruits. We also eat animals and animal products, such as meat, milk, and eggs. We eat fungi , such as mushrooms. We also eat algae, in edible seaweeds like nori used to wrap sushi rolls and sea lettuce used in salads. Bears are omnivores, too. They eat berries and mushrooms, as well as animals such as salmon and deer. Detritivores and Decomposers Detritivore s and decomposers make up the last part of food chains. Detritivores are organisms that eat nonliving plant and animal remains.
(PDF Download) A Cloud Forest Food Chain: A Who-eats-what Adventure in Africa (Follow That
For example, scavenger s such as vultures eat dead animals. Dung beetles eat animal feces. Decomposers, like fungi and bacteria, complete the food chain. Decomposers turn organic waste s, such as decay ing plants, into inorganic materials, such as nutrient-rich soil. They complete the cycle of life, returning nutrients to the soil or oceans for use by autotrophs. This starts a whole new series of food chains. Food Chains Food webs connect many different food chains, and many different trophic levels.
Food webs can support food chains that are long and complicated, or very short. For example, grass in a forest clearing produces its own food through photosynthesis. A rabbit eats the grass.
A fox eats the rabbit. When the fox dies, decomposers such as worms and mushrooms break down its body, returning it to the soil where it provides nutrients for plants like grass. This short food chain is one part of the forests food web. Another food chain in the same ecosystem might involve completely different organisms.
A caterpillar may eat the leaves of a tree in the forest.
A bird such as a sparrow may eat the caterpillar. A snake may then prey on the sparrow.presunvaha.cf
A coral reef food chain : a who-eats-what adventure in the Caribbean Sea - Hooksett Public Library
An eagle, an apex predator, may prey on the snake. A hawk, another apex predator, may prey on the eagle. Yet another bird, a vulture, consumes the body of the dead hawk. Finally, bacteria in the soil decompose the remains. In a desert ecosystem, an autotroph such as a cactus produces fruit.
Herbivorous insects, such as flies, consume the cactus fruit. Birds such as the roadrunner consume these insects. Detritivores such as termites eat the roadrunner after it dies. Bacteria and fungi help decompose the remaining bones of the roadrunner. The carbon in the bones enriches the desert soil, helping plants like cactuses develop.
Algae and plankton are the main producers in marine ecosystems. Tiny shrimp called krill eat the microscopic plankton. The largest animal on Earth, the blue whale, preys on thousands of tons of krill every day. Apex predators such as orcas prey on blue whales. As the bodies of large animals such as whales sink to the seafloor, detritivores such as worms break down the material. The nutrients released by the decaying flesh provide chemicals for algae and plankton to start a new series of food chains.
Biomass Food webs are defined by their biomass. Biomass is the energy in living organisms. Autotrophs, the producers in a food web, convert the suns energy into biomass. Biomass decreases with each trophic level. There is always more biomass in lower trophic levels than in higher ones. Because biomass decreases with each trophic level, there are always more autotrophs than herbivores in a healthy food web.
There are more herbivores than carnivores. An ecosystem cannot support a large number of omnivores without supporting an even larger number of herbivores, and an even larger number of autotrophs. A healthy food web has an abundance of autotrophs, many herbivores, and few carnivores and omnivores. This balance helps the ecosystem maintain and recycle biomass. In addition, smaller animals are more numerous than larger ones. Tigers and ants are both consumers in a tropical food web. However, it takes much more biomass to support a tiger population than a colony of ants.
Tigers consume more food and take up a much larger space. There are many more ants than tigers in the food web of a tropical ecosystem. Every link in a food web is connected to at least two others. The biomass of an ecosystem depends on how balanced and connected its food web is. When one link in the food web is threatened, some or all of the links are weakened or stress ed.
The ecosystems biomass decline s. The loss of plant life usually leads to a decline in the herbivore population, for instance. Plant life can decline due to drought , disease, or human activity. Forests are cut down to provide lumber for construction.