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What is a tertiary consumer?
A tertiary consumer in ecology is any organism that gets its nutrition from eating primary and secondary consumers. i.e. they feed on both members of the primary and secondary consumers in a food chain. They feeding on both secondary and primary consumers means that they can either be carnivores or omnivores.
Tertiary consumers are also referred to as apex predators and are usually at the very top of any ecological food chain. Energy is typically transferred through the food chain or food web by the organisms present in an ecosystem. Each organism in a food chain is assigned a trophic level, which is also known as its position.
There are several trophic levels in a food chain, and these trophic levels distinguish between different types of organisms. After producers, primary consumers, and secondary consumers, tertiary consumers are in the fourth trophic level. Their diet can consist entirely of meat or include both meat and plants. A hawk, for example, can feed on both primary and secondary consumers, such as birds and snakes.
Tertiary consumer definition in biology
Tertiary consumers are animals that eat other animals to get nutrition and most notably, they are at the top of the food chain. These animals can either be flesh-eaters (carnivores) or both plant and flesh-eaters (omnivores). The members of the tertiary consumers can be found occupying the fourth trophic level of the food web.
Tertiary consumer examples
- Big cats
- Polar bear
- Secretary bird
- Python and Boas
- Marine tertiary consumers
Tertiary consumers include a wide range of organisms found in both terrestrial and aquatic ecosystems and the above mentioned are some tertiary consumer examples. These examples will be discussed hereafter.
Humans are omnivorous in general; this means that they eat both plants and animals. They have a diverse diet and thus consume foods from all trophic levels and even eat decomposers like mushrooms. If humans consume only plant materials they are known as vegetarians, and as such, they are considered as primary consumers.
However, if humans choose to eat chicken that was fed only grains, they would be classified as secondary consumers, but if humans feed on the secondary consumer (chicken that feeds on plants and insects), they are known as tertiary consumers
. Humans are known as apex predators because they can use weapons to kill animals in the food chain or food web and they are not a source of food to other members of the trophic level. In other words, humans have no natural predators.
Other examples of tertiary consumers include lions, tigers, leopards, and other large cats. The big cats, with the exception of the leopard, are all apex predators because the cats have no natural predators, but leopards are occasionally predated by lions and tigers. The big cats exhibit a variety of characteristics for an apex predator which include;
- A lot of teeth
- Jaws that are powerful
- Claws that are large
- Tracking prey requires forward-facing eyes
- Muscles that are strong
- The ability to sprint at a high rate
Big cats eat animals at all trophic levels below them for example, herbivores that live in herds, such as zebras, wildebeest, and buffalo; and also secondary consumers like hyenas and foxes are also part of the menu of the big cats. Besides that, big cats are known to prey on large animals like crocodiles, and they hunt crocodiles on land because crocodiles have an advantage in the water and may attack big cats instead.
The polar bear is known to be the Arctic’s top predator and it is classified as a tertiary predator because it kills fish, seals, and penguins. A polar bear is considered a tertiary predator because it consumes a seal that has eaten a penguin that has eaten a fish, and this is due to the passage of several trophic levels during the process before the eventual capture of the seal.
Despite this complexity, polar bears are typically classified as tertiary and apex predators.
The secretary birds are well-known snake hunters as they hunt, kill, and eat a wide range of reptiles and small mammals. In fact, venomous snakes like adders and cobras are their preferred prey.
Adult secretary birds have extremely strong legs that can break human bones with a single strike and this powerful weapon renders this bird almost invincible. Although secretary birds are apex predators, their chicks are vulnerable to predation from other animals in the food chain.
The waters are ruled by crocodiles and are extremely powerful in water. They are known to have one of the most powerful jaws in the animal kingdom and this means they have one of the most potent bites and even big cats like tigers and lions can’t beat crocodiles in water because of the power of their bite. The crocodiles feed on both primary and secondary consumers. Especially when they try to cross the den of crocodiles or when they are taking water.
Python and Boas
Pythons can easily dispatch wildcats and foxes; however, they would struggle to outrun predators such as big cats and adult crocodiles. These colossal snakes are also capable of killing young big cats and crocodiles, for example, caimans which are much smaller than crocodiles, are normally prey for anacondas.
Marine tertiary consumers
Tertiary consumers are also abundant in marine ecosystems, for example, microscopic organisms that are known as zooplankton feed on phytoplankton, the primary producers in the aquatic environment, and many animals consume the zooplankton (secondary consumers).
These secondary consumers include jellyfish, crustaceans, and fish; and these secondary consumers are all food for the tertiary consumers. Some tertiary consumers examples in the ocean include;
- Large fish like barracuda, tuna, and groupers
- Seals and sea lions
- Moray Eels
Some of these organisms, like orca whales and great white or tiger sharks, are apex predators and they are tertiary consumers in addition to many seabirds, shearwaters, penguins, and gulls.
Names of animals that are tertiary consumers
- Moray Eels
- Sea lions
- Polar bear
The aforementioned list of animals shows the tertiary consumer examples that are found in both terrestrial and aquatic ecosystems.
List of tertiary consumers in the ocean
- Moray Eels
- Sea lions
List of tertiary consumers in the desert
- Gila monster
The animals listed above are some examples of tertiary consumers in the food chain found in the desert biome.
Functions of tertiary consumers
The energy contained inside organisms in an ecosystem is generally transmitted via a food chain or food web. Each organism in a food chain is assigned to a particular trophic level and the animals at the lower trophic levels are consumed by the animals occupying the higher trophic level.
At the top of the food chain, we usually have tertiary consumers who are not predated by any other animals and are known as apex predators. When tertiary consumers die, scavengers and decomposers consume their bodies.
Energy is expended and lost in the form of heat as it moves through each trophic level and this results in limited energy in the higher trophic levels. This lack of energy in higher trophic levels of the food chain makes it common for an ecosystem to have only four (4) trophic levels. This now leaves the members of the tertiary consumers to fulfill the role of the apex predator in any given ecosystem.
Importance of the tertiary consumer
Organisms at the top of the food chain play an important role in ecosystems by controlling the population of organisms in the lower trophic levels. They not only control the population of species at lower trophic levels, but they also change their behavior. i.e., Whenever the population of animals in the lower trophic levels is limited, the pressure of grazing or predation on the trophic levels below them is reduced and when this occurs, the ecosystem dynamics remain stable.
To demonstrate this phenomenon, consider foxes, hares, and hawks. Whenever the fox population becomes too large, it puts pressure on the hare population and the hawk regulates fox populations by predating on them, reducing the number of hares eaten by the foxes.
Are human tertiary consumers?
Yes, because they feed on members of the secondary consumers in any ecosystem.
Are fishes tertiary consumers?
Yes, because they feed on members of the third trophic level in the aquatic environment.