Sea anemone hitch hikes on the back of a hermit crab | Source:

Have you ever heard of relationships between two kinds of animals which are called symbiosis?  A mutualistic relationship, when two organisms of different species “work together” for each other’s beneficial is called a symbiotic relationship. If your cat or dog has ever had fleas, you’ve witnessed symbiosis in action. ‘Symbiosis’ comes from two Greek words that mean “with” and “living”. It is sometimes, but not always, beneficial to both parties.

In many cases, both species benefit from the interaction. This type of symbiosis is called mutualism. An example of mutualism is the relationship between sea anemone and hermit crab. Sea anemones hitch-hike on the back of hermit crabs, getting a free ride across the seabed and extending their tentacles to eat the crab’s leftovers. In return, the anemones fend off hungry octopuses and other predators using their barbed tentacles.

Penicillin mold on bread  |  Source:
Penicillin mold on bread |

The crabs return the favor by driving away creatures that eat anemones, such as starfish and fireworms. Pollination is another example for a mutualistic symbiosis. Pollinators, such as bees and butterflies and birds, receive nectar from plants while transporting pollen that the plants need for fertilization. Also, In the ocean, certain species, like shrimps and gobies, will clean larger fish. They remove parasites, dead tissue, and mucous and they feed on those waste.

Used and abused
Another face of symbiosis is commensalism. It is a type of relationship where one of the organism benefits greatly from the symbiosis while the other is not helped but is not harmed or damaged from the relationship. In other words, this is a one-sided symbiotic relationship. A hermit crab taking up residence in an empty seashell or a spider building a web on a tree are such one sided relationships in animal world. Parasitism is yet another type of symbiotic relationship.

The concept is fairly simple and it can be seen throughout nature. In parasitism, one organism benefits from the relationship, but at the expense of the other. The organism may live inside the other’s body or on its surface. In some of these parasitic relationships the host dies and in others, it is important that the host remain alive. Mosquitoes for example, represent one form of parasitism. Other kinds can be seen in animals that have fleas and ticks.

There’s another bit rare kind of symbiosis called amensalism, a relationship between two types of organisms in which the individuals of one type adversely affect those of the other and are unaffected themselves. There are many types of bacteria and fungi are perfectly capable of growing on bread under the right conditions. But, the bread mold Penicillium commonly grows on any bread that has passed its shelf life. This mold is capable of producing penicillin, which destroys many of the forms of bacteria that would also like to grow on this bread.

But the Penicillium does not directly benefited from the death of the other bacteria.

In nature, taking advantage of one specie and use it in a certain purpose is the basis of symbiosis. Basically, humans cannot live without symbiosis because feed on plants and animals for survival. Hence, at least one species wins. Overall, the world is indeed a mysterious place in which species use the other to ensure survival. As you can see, in food webs symbiosis is an entire process, a cyclical one to be more specific. In the natural world no organism exists in absolute isolation, and thus every organism must interact with each other organisms. Everything is connected to a symbiotic relationship sooner or later.

A tick on human skin after sucking blood. Pic by: Günther Blumenstock |  Source:
A tick on human skin after sucking blood.
Pic by: Günther Blumenstock |
The relationship between the sea anemone and clownfish allows the others to flourish through symbiosis.  |   Source:
The relationship between the sea anemone and clownfish allows the others to flourish through symbiosis. |
A bee at work ‘pollinating’  |
A bee at work ‘pollinating’ |
Cob web weaver and the tree |  Source:
Cob web weaver and the tree |