Symbiosis is any type of a close and long-term biological interaction, between two organisms.

  1. Mutualism: Both species benefit. This relationship is essential for many ecosystems, promoting survival and resource sharing.

  2. Commensalism: One organism benefits, while the other is unaffected. It often occurs in habitats where one species relies on another for transportation, shelter, or access to food.

    • Inquilinism: One organism lives within another’s habitat without affecting it, like birds nesting in trees.
    • Phoresy: One organism uses another for transportation, as in mites hitching rides on insects.
  3. Parasitism: One organism (the parasite) benefits at the expense of the other (the host), often harming but not killing the host.

    • Endoparasites: Live inside the host, like tapeworms in intestines.
    • Ectoparasites: Live on the surface of the host, like lice on mammals.
  4. Amensalism: One species is inhibited or harmed, while the other remains unaffected. This often involves competition for resources or release of toxins.

  5. Neutralism: Both species interact without affecting each other. Though true neutralism is rare in nature, it describes situations where neither species relies on nor harms the other.

Each type plays a unique role in ecosystems, shaping interactions that contribute to ecological diversity and evolutionary adaptations.