Question

Mac Arthur observed that five closely related species of warblers living on the same tree were able to avoid competition and co-exist by behavioral differences. This is an example of Competitive release, Resource partitioning, Competitive exclusion principle, Adaptive radiation?

Answer 1

This is an example of resource partitioning.

Resource partitioning:

1. Resource partitioning is the division of resources in an ecosystem to avoid interspecific competition for limited resources.
2. It's an evolutionary adaptation that allows different species to coexist in a given ecosystem.
3. The distribution of lizards in the Caribbean islands is a good example.
4. Insects are the main food source for lizards.
5. They can, however, live in a variety of microhabitats within their larger habitat.
6. Some lizards, for example, can live on the forest floor while others prefer to live in trees higher up in the habitat.
7. Because of the differentiation and partitioning of resources based on their physical location, different species can coexist more effectively.

Competitive release:

1. When a species is restricted to a small geographical area due to the presence of a competitively superior species, the competing species is experimentally removed, and the species expands its distributional range. This is referred to as a "competitive release."
2. A focal species, a competitor capable of excluding the focal species from the community, and a releasing factor capable of preventing such competitive exclusion make up the most basic competitive release system.
3. The Galapagos Islands' Abingdon tortoise became extinct within a decade of goats being introduced to the island, owing to the goats' superior browsing efficiency.

Competitive exclusion principle:

1. G.F. Gause proposed the principle of competitive exclusion, which states that two species competing for the same resources cannot coexist. Gause's law is another name for this law.
2. Two species cannot coexist if they occupy the same niche, according to the competitive exclusion principle (competing for identical resources). Natural selection may cause two species with overlapping niches to evolve more distinct niches, resulting in resource partitioning.
3. Because different birds have different beaks, what they eat is determined by the size and shape of the beaks.
4. As a result, while some birds can only eat small seeds, others can only eat large seeds.
5. This eliminates competition, allowing the two bird species to coexist peacefully.

Adaptive radiation:

1. Adaptive radiation is characterized by a rapid increase in the number of species that share a common ancestor, as well as a high level of ecological and morphological diversity.
2. The finches of Darwin are a classic example of adaptive radiation.
3. About two million years ago, their common ancestor arrived on the Galapagos Islands.
4. During that time, the Darwin's finches have evolved into 15 distinct species, each with its own body size, beak shape, song, and feeding habits.
5. Darwinian selection has resulted in changes in the size and shape of the beak, allowing different species to use different food resources such as insects, seeds, nectar from cactus flowers, and iguana blood.