Population interactions (+, −, 0)समष्टि पारस्परिक क्रियाएँ (+, −, 0)

NCERT Table 11.1 · Class 12 Biology · Chapter 11 · interactive diagram

Parts and their functions

• Mutualism (+ +) (सहोपकारिता (+ +)) — Both species benefit. Lichens (fungus + alga/cyanobacterium), mycorrhizae (fungus + plant roots), fig and its wasp, orchid Ophrys and its bee.
• Competition (− −) (स्पर्धा (− −)) — Both lose: fitness (r) of one species is significantly lower in the presence of the other. E.g. flamingoes and resident fishes compete for zooplankton in South American lakes.
• Predation (+ −) (परभक्षण (+ −)) — Predator benefits, prey is harmed. Tiger and deer; a sparrow eating seeds; herbivores are predators of plants.
• Parasitism (+ −) (परजीविता (+ −)) — Parasite benefits, host is harmed. Lice on humans, ticks on dogs, Cuscuta on hedge plants, cuckoo (koel) laying eggs in the crow’s nest (brood parasitism).
• Commensalism (+ 0) (सहभोजिता (+ 0)) — One benefits, the other is neither harmed nor benefited. Orchid on a mango branch, barnacles on a whale, cattle egret with grazing cattle, clown fish among sea anemone tentacles.
• Amensalism (− 0) (एमेंसलिज़्म (− 0)) — One species is harmed while the other is unaffected.

Original diagram drawn by Simple Learning Hub, based on NCERT Table 11.1. Report a mistake