Many species of animals on islands are larger than related species on the mainland. Scientists hypothesize that this phenomenon, called island gigantism, evolved in response to the scarcity of competitors and predators on islands. Reduced competition and predation allows species to exploit more resources and frees them from the need to hide in small refuges. True or false: The body temperatures of island tortoises always closely match the temperatures in their environments.

Verified step by step guidance

1. Identify the key concept: The question is about the body temperatures of island tortoises and how they relate to their environments.
2. Understand the biology of temperature regulation: Tortoises are ectothermic (cold-blooded) animals, meaning their body temperature is influenced by the external environment.
3. Consider the variability in environmental conditions: Island environments can vary significantly in temperature due to factors like sun exposure, shade, and altitude.
4. Analyze the statement: The use of 'always' in the statement suggests that there are no exceptions to the rule that the body temperatures of island tortoises match their environments.
5. Conclude based on biological principles: Since environmental conditions can vary and tortoises are ectothermic, it is unlikely that their body temperatures always exactly match the temperatures of their environments. Therefore, the statement is false.

Key Concepts

Island Gigantism

Island gigantism is a biological phenomenon where certain species of animals grow larger on islands than their mainland relatives. This size increase is often attributed to the absence of predators and competitors, allowing these species to exploit available resources more effectively. For example, giant tortoises on islands have evolved larger body sizes compared to their mainland counterparts, which helps them access different food sources and adapt to their unique environments.

Thermoregulation

Thermoregulation refers to the process by which organisms maintain their internal body temperature within a certain range, despite external environmental changes. In ectothermic animals, like tortoises, body temperature is influenced by the surrounding environment, making them susceptible to temperature fluctuations. This concept is crucial for understanding how island tortoises might adapt to their habitats, as their body temperatures can vary significantly based on environmental conditions.

Ecological Niche

An ecological niche encompasses the role and position a species has in its environment, including its habitat, resource use, and interactions with other organisms. In the context of island species, reduced competition and predation can lead to a broader niche, allowing species like island tortoises to thrive in various conditions. Understanding the ecological niche helps explain why island tortoises may not always match their environmental temperatures, as they adapt to the specific resources and conditions available to them.