Question

According to Darwin, organic evolution is due to
(a) Interspecific competition
(b) Competition within closely related species
(c) Reduced feeding efficiency in one species, possibly due to the presence of interfering species
(d) Intraspecific competition

Answer 1

Hint: It is an interaction in which organisms of different species compete for the same resource in an ecosystem. A classical example of this type of competition is Leopards and lions.

Complete answer:
According to Darwin, organic evolution is due to interspecific competition. It is usually believed that competition occurs when closely related species compete for the same resources, but this is not entirely true. Totally unrelated species could also compete for the same resource. Such interactions are termed as interspecific interactions. ‘Interspecific interactions’ arise from the interaction of populations of two entirely different species. They could be beneficial, neutral, or detrimental (neither harmful nor beneficial) to one of the species or both. One such example is interspecific competition
Further, let’s learn about the interspecific competition.
When Darwin talked about the struggle for existence and survival of the fittest in nature, he was convinced that ‘interspecific competition’ is a potent driving force in organic evolution. An example of this is visiting flamingoes and resident fishes competing for their common food, the zooplankton in the lake.
The feeding efficiency of one species might be affected due to the interfering and inhibitory presence of another species, even if resources like food and space are abundant.
So, the correct answer to this question is ‘Interspecific competition’.

Note:
- An example of competition within closely related species is a series of birds that might feed in the same trees for the same insects.
- Reduced feeding efficiency in one species, due to the presence of interfering species is sometimes also termed as ‘interference competition’.
- ‘Intraspecific competition’ is the competition between organisms of the same species.