Organisms and Populations

Population interactions - mutualism, competition, predation, parasitism

  1. Positive interaction includes mutualism/symbiosis/co-evolution, commensalism, proto-cooperation and scavengers.
  2. Mutualism (+/+) in organisms much possess obligate relationship. Eg: Termites – A flagellates ; Yucca – Pronuba (moth)
  3. Proto cooperation (+/+) exist in organisms with non-obligate relationship. Eg: Birds removing pest over the skin of animals self/cross pollination.
  4. Communalism (+/0) where one organism is benefited and other is almost unaffected. Eg: Epiphytes
  5. Exploitation, Amensalism, Competition are the three types of Negative interaction.
  6. Parasitism (+ : small / − : large) and predation (+ : large / − : small) are the 2 types of Exploitation.
  7. Hyper parasitism is when a parasite resides on another parasite. (Eg: Plasmodium residing in anopheles mosquito).
  8. Amensalism (−/0) is of 2 types Antibiosis and Allelopathy.
  9. Eg for Antibiosis
    (i) Penicillium → Staphylococcus
    (ii) Chlorello → Bacteria
    (iii) BGA (microcystis) → Fishes by the production of Hydroxylamine.
  10. Allelopathy is when plants producing toxic chemicals. Eg: Parthenium → Toxic chemical → Cassia tora
  11. Silver oak shows autopathy.
  12. Competition is the interaction b/w 2 species where both suffers (−/−) which is of 2 types interspecific and intraspecific.

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