SECONDARY CONSUMERS: CHARACTERISTICS AND EXAMPLES - BIOLOGY - 2024

A secondary or second order consumer is an organism that feeds on primary consumers to obtain the energy necessary to survive. All secondary consumers, whether carnivores or herbivores, must include primary consumers in their diet to survive.

The type of diet of these living beings is known as heterotrophic nutrition, since they obtain their energy by feeding on other organisms. Secondary consumers can be strictly carnivores, if they eat only meat, or omnivores if their diet is based on both plants and animals.

Foxes are secondary consumers, as they prey on primary

Characteristics of secondary consumers

Eagle that has caught a fox. Eagles are tertiary consumers, preying on secondary ones

As already mentioned, secondary consumers can be both carnivores and omnivores. For example, a toad that lives in the forest eats grasshoppers and other insects. In a forest foxes eat rabbits.

Small fish, crabs, and frogs inhabit the lakes that feed on tadpoles, small crustaceans, and tiny fish. Snakes are also secondary consumers, while they feed on mice (primary consumers).

Omnivores act like all types of consuming animals: primary, secondary, and tertiary.

The best example is the human being himself, who can eat berries and vegetables as a primary consumer. Likewise, he eats cattle, being then a secondary consumer. It also feeds on chickens, which in turn eat insects, which makes humans a tertiary consumer.

A distinctive feature of secondary consumers is that they can sometimes also be considered primary or tertiary consumers, depending on the environment. For example, when a squirrel eats nuts and fruits it is a primary consumer.

If this squirrel eats insects or baby birds, then it is considered a secondary consumer. This type of switching can occur at any time and in any environment, depending on the food and predators in that habitat.

Frozen tundras, arid savannas, and arctic waters are just a few of the extreme environments in which secondary consumers live. Whether on land or in water, the only thing they have in common is the type of food they eat: primary consumers.

Secondary consumers have adapted to exist in each type of ecosystem. Temperate regions are home to moles, birds, and other secondary consumers such as cats and dogs.

Previously, they were considered secondary consumers even to humans, since other mammals could easily hunt them. However, today humans are considered the ultimate tertiary consumer.

Examples of secondary consumers

Animals that often act as secondary consumers

• Cat
• Fox
• Chicken
• Snake
• Dog
• Owl

These can hunt primary consumers such as insects or small rodents and eat them, or feed on primary consumers that other animals have killed or injured.

Scavenger secondary consumers

• Crows
• Hawks
• Wolves

Secondary aquatic consumers

• Piranhas
• Small sharks

Roles of secondary consumers

Secondary consumers are an important part of the food chain, they control the population of primary consumers by obtaining energy from them. Secondary consumers, in turn, provide energy to the tertiary consumers who hunt them.

The most self-sufficient organisms, such as plants and other autotrophs, are at the base of the pyramid as they can produce their own energy. This is the first trophic level. Primary consumers (herbivores) constitute the second trophic level and secondary consumers constitute the third trophic level.

In any food web, energy is lost each time one organism eats another, so at a higher trophic level, more energy is lost. Self-sufficient organisms produce 100% of their own energy, whereas when a secondary consumer eats, they only receive 1% of the original energy available.

Therefore, it is necessary that there are more producers and eaters of plants than any other type of organism, in order to provide enough energy to the upper levels of the pyramid.

It does not follow from this that, because fewer secondary consumers are needed, they are less important. There is a delicate balance within the food chain.

If there are not enough secondary consumers, then the tertiary consumers face starvation, or worse, extinction, due to a shortage in the food supply.

If there were too many secondary consumers, then too many primary consumers would be eaten to the brink of extinction. Both extremes would break the natural order of the ecosystem.

Because of this, many more plants have to exist than plant eaters. Therefore, there are more autotrophs than heterotrophs, and more plant eaters than meat eaters.

Although there is intense competition between animals, there is also interdependence. When one species goes extinct, it can affect a whole chain of other species and have unpredictable consequences.

Secondary consumer types

Secondary consumers can be classified into two groups: carnivores and omnivores. Carnivores only eat meat or other animals.

Some secondary consumers are large predators, but even the smallest ones often also feed on herbivores larger than themselves to receive enough energy. Spiders, snakes, and seals are examples of carnivorous secondary consumers.

Omnivores, on the other hand, feed on both plants and animals for energy. Bears and skunks, for example, are omnivorous secondary consumers that hunt prey and eat plants.

However, some omnivores are simply scavengers. Instead of hunting, they eat the remains of animals that other predators leave behind. This is the case of opossums, vultures and hyenas, which obtain energy through carrion.

References

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3. "Difference Between 1st, 2nd & 3rd Level Consumers in a Food Web" in: Seattlepi Retrieved from: education.seattlepi.com.
4. Daniels, S. "Define Secondary Consumer" in: Sciencing Retrieved from: sciencing.com
5. "Food chain" in Wikipedia. (May, 2017) Recovered from: es.wikipedia.org.
6. "Food Chains and Food Webs: What's for dinner?" in: Enchanted Learning. (2016) Recovered from: enchantedlearning.com.
7. "Unit 4: Heterotrophs Acquire Energy" (Dec. 2013) MrFranta.org: Secondary Consumers. Recovered from: mrfranta.org.
8. "Trophic Levels" (2012) Clubensayos.com. Recovered from: clubensayos.com.