SYMBIOSIS ILLUSTATIVE EXAMPLES

2.3 Symbiosis VOCABULARY symbiosis mutualism commensalism parasitism host parasite Symbiosis refers to any close relationship between two different species. There are three types of symbiotic relationships: Mutualism is a relationship in which both species obtain some benefit from the interaction. Commensalism is an interaction in which one organism benefits while the other is unaffected. Parasitism occurs when one organism (the parasite) lives and feeds on, or in, the body of another organism (the host).

Commensalisms : Commensalism usually occurs between a species that is either vulnerable to predation or with an inefficient means of locomotion, and another species with a relatively effective system of defence.

Ex. Of Commensalism The Anemone crab on its host sea anemone.

Imperial shrimp hitching a ride on a Sea cucumber

One especially amazing example of commensalism occurs between the Pearlfish and a particular species of sea cucumber. The Pearlfish spends the day inside the alimentary tract (‘intestines’) of the sea cucumber, and at night emerges from its anus to feed on small crustaceans! In this manner it gets a safe place to live; and while not appearing to gain any benefit from the relationship, the cucumber is not harmed.

Parasitism : In a parasitic relationship, the host species is always exploited to some degree, although often in such a way that its health is impaired only slowly. This allows the parasite to exploit its host over a longer period. Many parasites only spend a portion of their lives in the relationship, either to reproduce, or during an initial growth stage.

Parasites can be divided into two basic categories, Ectoparasites and Endoparasites, the former referring to external parasites, and the latter internal parasites. Ectoparasites Endoparasites

Mutualism : Mutualism is one of the most interesting forms of symbiosis, as it is a benefit to both species involved.

the Boxer crab, carries a pair of small anemones in its claws the Boxer crab, carries a pair of small anemones in its claws. When approached by a predator it waves these around presenting the stinging tentacles so as to deter the marauder. The anemones benefit from the small particles of food dropped by the crab during feeding.

Mimicry ; Mimicry is a form of symbiosis where a species may mimic the colours, patterns, or even behaviour of another species for one of two reasons. Either to be able to get closer to unsuspecting prey or in the case of a harmless species; to gain protection by imitating a predator or poisonous species.

One of the most interesting mimic species is the Mimic octopus One of the most interesting mimic species is the Mimic octopus. It takes on the form of a variety of different animals by bunching up or elongating its arms to mimic anything from a stingray to a Lionfish or even a sea-snake. It could be that this species employs mimicry both as a means of defence and predation

A particular type of mutualistic interrelationship that many divers will have encountered is ‘Cleaning symbiosis’, The fish being cleaned are often termed ‘client fish’ and the sites they go to to be cleaned are known as ‘Cleaning stations’ ... in tropical waters these areas of the reef are quite clearly defined by the numbers of stationary fish and their attendant cleaner organisms.

2.5 Ecological Pyramids VOCABULARY ecological pyramid food pyramid pyramid of energy pyramid of numbers pyramid of biomass Ecologists use three different types of ecological pyramids to illustrate ecosystems: Pyramid of energy: represents how much energy is available in each trophic level Pyramid of numbers: represents the actual number of organisms present in each trophic level Pyramid of biomass: represents the total mass of living things in each trophic level

Energy Pyramid 2nd Law of Thermodynamics: energy is not transferred from one object/organism to the next with 100% efficiency Some of the energy is lost to the environment Energy Pyramid shows the amounts of energy that moves from one level to the next

Sample Energy Pyramid

Energy Transfer Only about 10% of energy is transferred from one level to the next The other 90% is used by the organism to carry out its life processes or it is lost to the environment

Predator - Prey Lab Do the Chapter Review