Question

Given below are few common population interactions. Choose the option which matches A and B correctly.

Species 1	Species 2	Species 3
-	-	A
+	-	B

• A. A - Competition, B - Commensalism
• B. A - Competition, B - Parasitism
• C. A - Parasitism, B - Competition
• D. A - Parasitism, B - Commensalism

Answer 1

The correct option is B A - Competition, B - Parasitism

Competition is a type of population interaction in which two species compete for the same resources that are limiting. This has a negative effect on both the interacting species (-/- interaction). Example - In some shallow South American lakes, visiting flamingoes and resident fish compete for zooplanktons, their common food.
Hence, A is competition.

Parasitism is a type of population interaction between two living species in which one organism is benefited at the expense of the other. The organism that is benefitted (+) is called the parasite, while the one that is harmed (-) is called the host. Example - Ticks on dogs.
Hence, B is parasitism.

Commensalism is a type of population interaction in which one species benefits (+) and the other is neither harmed nor benefited (0). So it is a +/0 type of interaction. Example - Orchids growing on a mango tree. Hence option c is incorrect.


Commensalism is a type of population interaction in which one species benefits (+) and the other (+/o) is neither harmed nor benefited. So it is a +/0 type of interaction. Example - An orchid growing as an epiphyte on a mango tree branch.

Parasitism is a type of population interaction between two living species in which one organism (the parasite) lives and derives nutrition from another specific organism (the host)