Symbiosis

Symbiotic relationships

In nature Symbiotic relationships may take various forms. Parasitism, Commensalism, Amensalism and Mutualism. I am not going to discuss amensalism in any great detail because it is a very rare form. However the three most common types of symbiotic relationships are: Parasitism, Commensalism, Mutualism

• Parasitism

  This is one of the most common of the symbiotic relationships. With the parasitism, one of the organisms (the parasite)benefits from the interaction, whilst the other organism (the host)is usually affected negatively.

• Commensalism

  Commensalism is a positive interaction or relationship between two organisms in which only one partner benefits and the other is not harmed. This is usually associated with a feeding scenario, and describes where one species benefit and the other is not affected. A common form is Cattle Egrets following Buffalo, feeding off the insects that are disturbed.

• Metabiosis – Where one species uses something made by a second species. Usually after its death, a hermit crab using a Gastropod shell to live in.
• Inquilism – The second organism is used directly for housing, protection or structural support. Animals using holes in trees to live in. Male Paper Nautilus  lives in female shell, Hornbills.
• Phorsey – One species using another for transportation to get to a desired area. Mites using dung beetles to get to dung to feed on fly eggs and larvae.

• Amensalism

  This is a rare form of the symbiotic relationships, where one species is not affected (it does not benefit or suffer) while the other suffers.It usually occurs when one species releases chemical compounds as part of its normal metabolic functions.  These compounds have a detrimental affect on other organisms. There are basically two types of Amenssalism, competition and antibiosis.

• Competition – In competition, a larger or more powerful organism excludes another organism from its source of shelter or food.
• Antibiosis – during antibiosis, one organism secretes a chemical that kills the other organism, while the one that secreted the chemical is unharmed. One species releases chemical compounds as part of its normal metabolic functions and these have a detrimental affect on other organisms. Two examples of antibiosis amensalism are provided by the bread mold Penicillium and black walnut trees.

       Penecillium.

• 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. It is this understanding of the bacteria-killing properties of penicillin that led to the use of it as an antibiotic medicine. The Penicillium (spelled correctly) does not benefit from the death of the other bacteria, making this an example of antibiosis amensalism
• Black walnut trees.Walnut roots exude juglone which is toxic to other plants, stopping their seeds from germinating or preventing them from actually growing well.

• Mutualism

  Mutualism is also a positive interaction or relationship between two organisms where both organisms benefit from the interaction.This is an account of mutualism and parasitism within the bio diverse Fernkloof Reserve in Hermanus. The symbiotic relationship in this case, involves two types of symbiosis – mutualism and parasitism. Mutualism is between the tree Kiggelaria africana commonly known as the Wild peach, and the Klaas’s cuckoo.

  Brood parasitism occurs when the Klaas’s cuckoo lays up to 24 eggs in one breeding season and chooses a host bird from a selection of 16 species to incubate and rear their young. The Kiggelaria africana is the host tree to the acraea horta butterfly and her caterpillars on which the cuckoo feeds.