ConsumersConsumers are heterotrophs that feed on living organisms by ingestion.
|
|
Multicellular organisms however, carry food to their digestive system by swallowing it, as is the case of the lion eating the zebra in the photograph to the left.
Detritivores & Saprotrophs
Organisms produce waste in the form of large quantities of organic matter, such as dead leaves (and other parts of plants); feathers, hairs and other dad parts of an animal's body; and feces from animals. If this were to accumulate in an ecosystem, it would become toxic and kill everything, so instead, it is used as a source of nutrition by two groups of heterotroph organisms: detritivores and saprotrophs.
Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion. These organisms ingest dead organic matter and, like consumers do with other organisms, they digest it internally and absorb the products of digestion. This can be done in different ways. Larger, multicellular detritivores such as earthworms, take the dead organic matter into their gut, while unicellular organisms ingest it into food vacuoles, where, as always it is broken down by enzymes. An interesting detritivore is the larvae of dung beetles, which feed by ingestion of feces rolled into a ball by their parents. This sounds quite unpleasant, but in fact, dung beetles are one of the few insects that demonstrate parental care behaviour. Actually, these animals are quite fascinating! For example, as they roll these balls of feces that become the nest to their offspring by pushing it with their hind legs, dung beetles use the navigate by using the stars as guidance! Watch a video about dung beetles life cycles and habits and how they are useful for the earth:
Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion. These organisms ingest dead organic matter and, like consumers do with other organisms, they digest it internally and absorb the products of digestion. This can be done in different ways. Larger, multicellular detritivores such as earthworms, take the dead organic matter into their gut, while unicellular organisms ingest it into food vacuoles, where, as always it is broken down by enzymes. An interesting detritivore is the larvae of dung beetles, which feed by ingestion of feces rolled into a ball by their parents. This sounds quite unpleasant, but in fact, dung beetles are one of the few insects that demonstrate parental care behaviour. Actually, these animals are quite fascinating! For example, as they roll these balls of feces that become the nest to their offspring by pushing it with their hind legs, dung beetles use the navigate by using the stars as guidance! Watch a video about dung beetles life cycles and habits and how they are useful for the earth:
Differing from detritivores, saprotrophs are heterotrophs that obtain organic nutrients from dead organic matter by external digestion. They do this by secreting digestive enzymes into the dead organic matter and thus digesting it externally and absorb the products of such digestion. Many types of bacteria and fungi are saprotrophic, also known as decomposers because of the breaking down of carbon compounds in dead organic matter and release of elements such as nitrogen into the ecosystem-which are then used again by other organisms.