Omnivore
Omnivore
An omnivore is an animal that eats both plants and other animals. Because of the wide variety in their diet, omnivores are adaptable to many different environments. They also can be found at several different levels on a food web (the connected network of producers, consumers, and decomposers).
Unlike carnivores who eat a diet almost completely of meat, and herbivores who eat only plants, omnivores are generalists when it comes to what they can and will eat. One of nature's principles is that animals' bodies are adapted to what they eat. Their systems are designed with their diet in mind. Therefore, carnivores, who must hunt and kill other animals in order to eat their flesh, are designed for those purposes. Their senses are sharp, they have deadly claws and teeth, and their digestive systems are prepared to process high-protein meat. On the other hand, herbivores do not have to track, catch, and kill their food. Since they eat only green plants, herbivores need only find and eat these plants. Their teeth are not sharp and pointed but are designed for grinding tough plant material. Herbivores' digestive systems are also specially built to break down cell walls made of cellulose (the main component of plant tissues) by containing microorganisms just for that purpose.
The name omnivore is taken from the Latin omnis meaning all, and vorare to eat or devour. According to this broad definition, humans are probably the most omnivorous of all animals, since they can eat almost anything. Besides classifying animals as omnivore, carnivore, or herbivore, biologists categorize the larger group of all living things as autotrophs or heterotrophs.
Autotrophs, like all plants and some bacteria, can make their own food. Heterotrophs (like animals) cannot make their own food and must eat plants or other animals. Autotrophs are considered to be producers since they are at the first level of the food chain (the series of stages energy goes through in the form of food). This is because the food they make supports all other life in the chain. Heterotrophs are considered to be consumers since they cannot make their own food and must eat others (plants or animals) to survive. Omnivores are also heterotrophs.
Unlike herbivores, who always are one level above the plants they eat, different omnivores can be found at different levels on the food chain at different times. Omnivores can be first-level consumers because they eat plants, but they can also be higher up since they also eat animals. For example, a bear will eat berries as well as a fish.
Many kinds of mammals are omnivores, such as humans, pigs, bears, apes, raccoons, and hedgehogs. Because of this varied diet, their digestive systems are not as specialized as others who eat only one type of food. Carnivores have a short digestive tract since their systems must break down easy-to-process protein. Herbivores, however, have elaborate and multichambered stomachs to process and reprocess the hard-to-break-down cell walls of the plants they eat. Omnivores have intermediate digestive systems that can handle both meat and plants. It would seem that the varied food supply of omnivores gives them an advantage over other more specialized eaters.
Omnivore
Omnivore
An omnivore is any animal that is a generalist feeder, consuming a wide variety of foods that can include both animal and plant matter . Because they have attributes of both carnivores and herbivores, omnivores have relatively diverse linkages within ecological food webs.
Some examples of omnivorous animals are pig and bear, both of which will eat a remarkably wide range of plant and animal products. Most wild populations of these animals are primarily herbivorous, eating a wide variety of plant products, depending on their seasonal and geographic availability. However, both of these animals are also opportunistic meat eaters. If meat can be readily attained through predation or scavenging, these animals will eagerly avail themselves of this food.
Interestingly, humans are the most omnivorous of all animals. Only a limited number of plant and animals species , about 100, are actually consumed by humans in relatively large quantities. However, products of additional thousands of plant and animal species are consumed as victuals by humans, as long as the food is nutritious and there is access to the resource. In a few cases, humans even consume some foods that are potentially extremely poisonous, usually for cultural reasons, or because in small amounts the toxin may act as a hallucinogen. One extreme case is the consumption by Japanese (especially men) of flesh of a puffer fish known as fugu (Spheroides rubripes) in sushi restaurants. This meal is prepared with exquisite care by highly skilled chefs, who must excise a small gland containing an extremely toxic biochemical called saxitoxin. If this preparation is not accomplished properly, then the meal will be quickly lethal to the patron. Because of this danger, the eating of fugu is considered to be an act of great bravado, for which the consumer gains respect in the eyes of his peers. This deliberate exposure to such an extraordinarily toxic food is symptomatic of the remarkable omnivory displayed by humans.
See also Carnivore; Food chain/web; Herbivore.
Bill Freedman
Omnivore
Omnivore
An omnivore is any animal that is a generalist feeder, consuming a wide variety of foods that include both animal and plant matter. Omnivores may assume diverse roles within ecological food webs, acting as primary consumers when eating plant material or acting as a much higher-level consumer when eating meat.
Some examples of omnivorous animals are pig and bear, both of which will eat a wide range of plant and animal products. Most wild populations of these animals are primarily herbivorous, with their consumption of plant types dependent on seasonal and geographic availability. However, both of these animals are opportunistic meat eaters. If meat can be readily attained through predation or scavenging, they will consume it.
Humans are also omnivorous. The human diet is primarily composed of only about 100 plant and animal species. However, the products of thousands of additional plant and animal species are consumed in smaller quantities by humans.
See also Carnivore; Food chain/web; Herbivore.
Bill Freedman
omnivore
omnivore
omnivore
omnivore
Stuart Judge