Question

A relationship in which a sea anemone attached to shell of the hermit crab is called as
A. Mutualism
B. Protocooperation
C. Amensalism
D. Commensalism

Answer 1

Hint: Symbiosis is a close and long-term biological interaction between two different organisms. A truly symbiotic relationship is one where both organisms are benefiting each other unless the habitat of both organisms is known.

Complete answer:
A. Mutualism- Mutualism is an association of two different species in which they both are mutually benefiting each other and no one is harmed. It is a common type of ecological interaction. For example- Ants live and feed on the acacia trees nectar; here ants are mutualist whereas trees are the host.
B. Protocooperation- Protocooperation is where two species interact with each other beneficially but a relationship is not necessary. Cooperating species do not depend upon each other for survival. For example- Predatory birds sit on cattle as this bird eats ectoparasites like leeches, etc.
C. Commensalism- Amensalism is an ecological interaction where one species causes harm to another organism without any benefits to itself. In this interaction, one species is harmed while the other is unaffected. For example- In an interaction between penicillium and bacteria, penicillium secretes penicillin (first antibiotic) which is highly toxic to bacteria.
D. Commensalism- Commensalism is a type of symbiotic relationship where one species is benefitted while the other species is neither harmed nor benefitted. Species that gain the benefit is known as commensal. For example- Sea anemone attached to the shell of the crab.
Sea anemones have stinging cells which are useful for both stunning prey as well as for protection against possible predators. Hermit crab also benefits as it gets protection from predators with sea anemone attached to its shell. At the same time, sea anemone feeds on the prey that floats or swims into its tentacles. As the crab moves sea anemone has a greater chance of utilizing different food sources.

Hence, the correct answer is option (D).

Note: Commensalism is also used by plants, many plants produce seeds that attach to a passing animal via barbs or hooks, and then they fall off to grow into a new plant away from the parent plant.