Positive species interaction

Commensalism,Proto co-operation and Mutualism with examples

1. POSITIVE SPECIES INTERACTION Presented by, Sonia John II M.Sc.Zoology

2. INTRODUCTION No organisms under natural conditions is divorced from all other living things Species interact with each other in one way or the other: Intraspecific Interactions- associations,aggregations Interspecific Interactions:- (a)Positive interactions (b) Negative Interactions

3. POSITIVE INTERACTIONS When the interactions result in a benefit for one or both of the species and harm to neither. Result in better growth, reproduction and survival Not static and they vary in their strength and symmetry depending upon the context under which they occur. Types: Commensalism Proto Co-operation Mutualism

4. Commensalism Association of two or more species;associated for activities such as food; one species at least derives benefit from the association while the other species are neither benefitted nor harmed. Commensal - species that benefits from the association; May obtain nutrients,shelter,support etc from the host species which is substantially unaffected Often between a large host and a smaller commensal

5. Ecto Commensal - Epizoite animals; Associated with other animal for the purpose of anchorage and protection Eg : Whale and Barnacles Endo Commensal - When the commensalism is internal Eg:Harmless protozoans in the intestinal tract of humans

6. EXAMPLES Whale and Barnacles: Barnacles during their final larval stage attach to the skin of whale Later on, they secrete a hard calcareous layer thus fixing them onto the skin of the whale Get 2 benefits: ( i )Food (ii) Protection from predators

7. 2.Remora Fish and Shark Remora fish attach to the bellies of shark by means of a dorsal fin highly modified to form a sucker Gets a free ride when the host moves about Food scrapes of the shark are swept up by the Remoraa

8. 3 .PseudoScorpions and Insects Some species of Pseudoscorpions hide themselves under the wing covers of large insects like beetles. This gives them protection from their predators, and also provides them a means of transportation over a larger area. Because of its small size and lack of sting, it does not harm the beetle in any way.

9. 4.Hermit Crab Living in the Gastropod Shell

10. TYPES OF COMMENSALISM Chemical commensalism: Often b/w 2 species of bacteria Inquilism : One species using the body or body cavity of another organism. Eg : Whale and barnacle Metabiosis : One species unintentionally creates a home for another species through one of its normal life activities. Eg:hermit crab in gastropod shells Phoresy : When one organism attaches to the other for gaining transportations. Eg : mites on insects

11. PROTO CO-OPERATION Interaction clearly beneficial to both species; However not obligatory for either species.  Growth and survival is possible in the absence of the interaction Examples: Ants and aphids Red Billed Oxpecker and Impala Water moccasin and large birds

12. 1.Red Billed Oxpecker and Impala  This bird eats mainly ticks but may also eat blood-sucking flies, fleas, and lice off the Impala Both organisms benefit from this because the Impala is getting rid of the parasites that could harm it. The oxpecker benefits from it because it is getting food. But this association is not obligatory for both

13. 2.Ants and Aphids Ants searches for the food on trees an shrubs which are hosts to the honey-dew secreting Aphids Some species of ants farm the aphids,stimulate them to secrete honeydew and also protect them The honey dew secreted by the aphids are used as food by the ants

14. 3.Water moccasin and large birds(Heron) These birds nest in the lower branches of trees while the water moccasin congregate around the bases This protects the bird from tree climbing predators such as raccoons The snake feed,in turn,is dropped by the birds

15. MUTUALISM Obligatory interaction that is strongly beneficial to both species. 2 organisms of diff species associates and each individual benefits from the other. Term introduced by Pierre Joseph van Beneden in 1876

16. Examples The lichen is a mutualistic association between a species of algae and a species of fungus Mycorrhizal association Bacteria in the intestine of herbivorous birds and mammals Mutualism in Trichonympha in the gut of termites Spider crab and algae

17. 1.Lichen Mutualistic association between a species of algae/ cyanobacteria and a species of fungus The fungus benefits :because algae or cyanobacteria produce food by photosynthesis The algae or cyanobacteria benefit :by being protected from the environment by the filaments of the fungus, which also gather moisture and nutrients from the environment, and (usually) provide an anchor to it.

18. 2.Trichonympha in the gut of termites Although termites are insects that eat wood, termites are not capable of digesting wood on their own. Trichonympha have the enzymes needed to convert cellulose in wood into starches and sugars that the termite can use as nutrients. In exchange, these organisms benefit from a continuous supply of energy-rich cellulose and a suitable environment in which to live.

19. 3.The spider crab and the algae. Spider crabs live in shallow areas of the ocean floor, and greenish-brown algae lives on the crabs' backs, making the crabs blend in with their environment, and unnoticeable to predators. The algae gets a good place to live, and the crab gets camouflage.

20. REFERENCES Agarwal.V.K and P.S.Verma.Principles of Ecology.S.Chand Publications Arora.M.P . Ecology. Himalaya Publishing House. http://en.wikipedia.org www.tutorvisita.com www.buzzle.com