Problem 2 - Campbell Biology

Question

The principle of competitive exclusion states that (A) two species cannot coexist in the same habitat. (B) competition between two species always causes extinction or emigration of one species. (C) two species that have exactly the same niche cannot coexist in a community. (D) two species will stop reproducing until one species leaves the habitat.

Step-by-Step Solution

Answer

C

Step 1 - Understand the Principle of Competitive Exclusion

The principle of competitive exclusion, also known as Gause's Law, states that two species that compete for the exact same resources cannot stably coexist. One species will outcompete the other, leading to the exclusion of the less competitive species.

Step 2 - Analyze Each Option

Evaluate each option to see which one accurately reflects the principle of competitive exclusion: (A) Two species cannot coexist in the same habitat. (B) Competition between two species always causes extinction or emigration of one species. (C) Two species that have exactly the same niche cannot coexist in a community. (D) Two species will stop reproducing until one species leaves the habitat.

Step 3 - Eliminate Incorrect Options

Review each statement for accuracy: (A) Not necessarily true, as two species can coexist in the same habitat if they have different niches. (B) Incorrect, as competitive exclusion specifically refers to species with identical niches, not every instance of competition. (D) Incorrect, as it misinterprets the principle by suggesting species will stop reproducing.

Step 4 - Identify Correct Option

Option (C) accurately describes the principle of competitive exclusion: Two species that have exactly the same niche cannot coexist in a community because one species will always outcompete the other.

Key Concepts

Gause's Law

Gause's Law, also known as the principle of competitive exclusion, is a fundamental concept in ecology. It was formulated by the Russian biologist Georgii Gause. This law states that two species that compete for the exact same resources cannot cohabit stably in the same environment. One species will invariably outcompete the other, leading the less competitive species to become extinct or to migrate to a different habitat. Gause's Law highlights the importance of resource differentiation and habitat specialization in maintaining biodiversity. It teaches us that for two species to coexist, they must utilize different resources or occupy different ecological niches.

Niche Differentiation

Niche differentiation is a process that allows multiple species to coexist in the same environment by minimizing direct competition. It involves species evolving and adapting to exploit different resources or to occupy various niches within an ecosystem. By doing so, each species reduces competition, allowing them to coexist more peacefully.

Several mechanisms enable niche differentiation:

• Spatial differentiation: Species occupy different physical spaces within the habitat.
• Temporal differentiation: Species are active at different times, such as nocturnal vs. diurnal activity.
• Resource partitioning: Species evolve to use different parts of the resource spectrum, for example, different food types.

Niche differentiation is vital for preserving biodiversity and enabling multiple species to thrive within the same ecosystem.

Species Coexistence

Species coexistence refers to the ability of multiple species to live together in the same environment without driving each other to extinction. Coexistence is achieved through various strategies that minimize direct competition and allow each species to survive and reproduce. These strategies include niche differentiation, mutualistic relationships, and adaptive behaviors that reduce direct resource competition.
By understanding the principles of species coexistence, ecologists can better grasp the complex web of interactions within ecosystems. This knowledge is crucial for conservation efforts, ecosystem management, and understanding the impacts of environmental changes on biodiversity.

Competitive Interactions

Competitive interactions occur when multiple species vie for the same limited resources, such as food, light, or space. These interactions can have significant impacts on the survival and distribution of the species involved. Competitive interactions can be categorized into two main types:

• Intraspecific competition: Competition among individuals of the same species.
• Interspecific competition: Competition between individuals of different species.

Interspecific competition is central to Gause's Law and the principle of competitive exclusion. When two species compete directly for identical resources, one will outperform the other, leading to the local extinction or migration of the less competitive species. Understanding competitive interactions helps ecologists predict species distribution and the outcomes of species introduction or habitat changes.