Question

1a) In the past, a hypothetical coral reef community contained only one carnivorous fish species. However, recently, a new carnivorous fish species has established a population in this community. If the two fish species eat the same prey, the competitive exclusion principle predicts that ____________.

1. all the prey fish will be consumed leading to the extinction of both species
2. the newly established species will always outcompete the other species
3. the species that arrived first in the community will always be the stronger competitor
4. the fish species that is the weaker competitor will decline in population size, perhaps to zero
5. the realized niche of the two species will overlap

1b) If important carnivores are removed from a forest community, the most visible result is ___________.

1. not predictable because of the complexity of ecosystems
2. the beginning of secondary succession
3. a reduction in available plant material in the community
4. rapid evolution of other species in the community
5. an increase in the available plant material in the community

1c) The carrying capacity of a population determines the population’s _____________.

1. biogeographical range
2. fundamental niche
3. size
4. rate of evolution
5. average fecundity

1d) An organism’s fundamental niche is usually __________.

1. broader than its realized niche
2. narrower than its realized niche
3. more important than abiotic variables for affecting a species distribution
4. shared by closely-related species
5. none of the above

Answer 1

1a. D is the right option.

Competitive exclusion principle states that the organism which is competitively superior will gradually eliminate the other organism from the region. Two organisms competing for the same resource can't live together in a given habitat.

1b.. C is the right option.

This is because, when an important carnivore is removed the prey population will increase in the absence of the predator. The herbivores in this case will increase in their number. Increase in herbivore population will lead to over grazing on the producers. So it leads to reduced plant population in the region.

1c. Option C is the right one.

Carrying capacity is the number of organisms a habitat can support indefinitely. So size of the population in a given habitat depend on the resources available in the given region.

1d. OPtion A is the right one.

A fundamental niche is larger than the realized niche. Realized niche is the place where an organism actually resides because of the presence of predators, competitors etc.