Question

Which of the following is not a characteristic of a stable biological community?

• A. It must be resistant to invasions by alien species.
• B. It should not show too much variation in productivity year to year.
• C. All species are equally important and the absence of any one leads to unsustainability.
• D. It is resilient to occasional disturbances, natural or man-made.
• A. Key species
• B. Endemic species
• C. Community
• D. Species
• A. Paul Ehrlich
• B. David Tilman
• C. Robert May
• D. Edward Wilson
• A. Reptiles
• B. Fishes
• C. Insects
• D. Mammals
• A. Temperate regions are subjected to glaciations, but tropical latitudes remained relatively undisturbed.
• B. Tropical environments have more humidity/moisture which helps diversity flourish.
• C. Tropical environments are less seasonal and more constant.
• D. There is more solar energy available in the tropics which contributes to higher productivity and biodiversity.

Answer 1

The Correct Option is C

In a stable biological community, there are several key characteristics that ensure its sustainability and robustness. Let's examine the options provided to identify which one does not characterize such a community:

1. It must be resistant to invasions by alien species.
2. It should not show too much variation in productivity year to year.
3. All species are equally important and the absence of any one leads to unsustainability.
4. It is resilient to occasional disturbances, natural or man-made.

Now let's analyze each option:

1. Resistance to invasive species is a hallmark of a stable community, as alien species can disrupt existing relationships and resources.
2. Consistency in productivity is important because major fluctuations can destabilize resources and interactions within the community.
3. This option suggests that every species is irreplaceable, which contradicts the principle of functional redundancy where multiple species can fill similar ecological roles, thus providing stability to the ecosystem.
4. Resilience to disturbances ensures that the community can recover and maintain its ecological functions, even after disruptions.

Based on these analyses, the option that is not a characteristic of a stable biological community is:

All species are equally important and the absence of any one leads to unsustainability.

This is because a stable ecosystem often has a redundancy that allows it to adapt to changes and sustain itself even when some species are not present.

Answer 2

(1) It must be resistant to invasions by alien species.

This statement is correct. A stable biological community is typically resistant to invasions by alien species. Resistance to invasions is a characteristic of a stable and mature ecosystem.

(2) It should not show too much variation in productivity from year to year.

This statement is correct. A stable biological community tends to have relatively consistent productivity over time, with minimal variation from year to year. This consistency is indicative of a stable ecosystem.

(3) All the species are equally important in a stable community and the absence of any one leads to its unsustainability.

This statement is incorrect. In a stable biological community, not all species are equally important. Some species, known as keystone species, play a critical role in maintaining the structure and function of the community. The absence of a keystone species can have a significant impact, but the absence of other species may not necessarily lead to the community's unsustainability. The importance of species can vary, and some species may be more redundant or less critical to the overall stability of the community.

(4) It is resilient to occasional disturbances, whether natural or man-made.

This statement is correct. A stable biological community is resilient to occasional disturbances. Resilience is the ability of an ecosystem to recover from disturbances and maintain its structure and function.

Conclusion

The incorrect statement is (3) All the species are equally important in a stable community and the absence of any one leads to its unsustainability.

Answer 3

The 'rivet popper hypothesis' is a metaphor first proposed by ecologist Paul Ehrlich. In this analogy, each species is considered a 'rivet' that holds an ecosystem's structure together, similar to how rivets are used to hold the panels of an airplane together. Removing one species (or rivet) might not immediately lead to catastrophic failure, but as more species are lost, the ecosystem's structural integrity becomes increasingly compromised, potentially leading to collapse.

Therefore, in this hypothesis, the term 'rivet' signifies Species.

Answer 4

(1) Key species

This statement is incorrect. While the Rivet Popper Hypothesis does highlight the importance of key species, the "rivet" in the analogy represents any species within the ecosystem, not just key species.

(2) Endemic species

This statement is incorrect. The "rivet" in the Rivet Popper Hypothesis represents any species within the ecosystem, not specifically endemic species.

(3) Community

This statement is incorrect. The "rivet" in the Rivet Popper Hypothesis represents individual species, not the community as a whole.

(4) Species

This statement is correct. In the Rivet Popper Hypothesis, the "rivet" signifies any species within the ecosystem. The hypothesis, proposed by Paul Ehrlich, compares an ecosystem to an airplane where each species is like a rivet holding the plane together. Removing a rivet (losing a species) may not immediately affect the plane's (ecosystem's) stability, but as more rivets are removed, the plane becomes weaker, illustrating the cumulative impact of species loss on ecosystem stability.

Conclusion

The correct answer is (4) Species. The "rivet" in the Rivet Popper Hypothesis signifies any species within the ecosystem.

Answer 5

In the field of ecology, the concept that species richness—or the number of different species within a community—can directly impact the stability of that community has been an intriguing area of study. Stability in this context refers to the community's ability to maintain its structure and function over time, despite external stressors. The scientist who significantly contributed to this understanding by providing evidence for the correlation between species richness and community stability is David Tilman.

Tilman's research demonstrated that ecosystems with greater biodiversity tend to be more resilient and stable, supporting the hypothesis that diversity plays a critical role in ecological health. His findings are crucial in conservation biology, emphasizing the importance of preserving diverse ecosystems to ensure long-term stability and functionality.

Answer 6

(1) Paul Ehrlich

Paul Ehrlich is known for his work on population biology and the concept of the "rivet popper hypothesis," but he did not prove the direct correlation between species richness and community stability.

(2) David Tilman

David Tilman conducted long-term ecosystem experiments that demonstrated a direct correlation between species richness and the stability of a community. His research showed that plots with more species had less year-to-year variation in total biomass, indicating greater stability.

(3) Robert May

Robert May is known for his theoretical work on the stability and complexity of ecosystems, but he did not directly prove the correlation between species richness and community stability through experimental research.

(4) Edward Wilson

Edward Wilson is renowned for his work on biodiversity and sociobiology, but he did not conduct experiments to prove the direct correlation between species richness and community stability.

Conclusion

The correct answer is (2) David Tilman, as his research provided empirical evidence that species richness directly correlates with the stability of a community.

Answer 7

Among the vertebrates, the most species-rich group is fishes. The term "vertebrates" refers to animals with a backbone, including several major classes such as mammals, birds, reptiles, amphibians, and fishes. Although insects are highly diverse, they are not vertebrates and thus are not included in this comparison. Fishes, which comprise the most diverse group of vertebrates, have a vast number of species spread across various aquatic habitats.

This diversity renders them the most species-rich group among vertebrates. Consequently, the correct answer is fishes.

Answer 8

To solve the question of which hypothesis does not explain the greatest biological diversity in the tropics, we must analyze each option:

1. Temperate regions are subjected to glaciations, but tropical latitudes remained relatively undisturbed.
   This hypothesis suggests that historical climate stability in tropical regions allows for consistent biodiversity.
2. Tropical environments have more humidity/moisture which helps diversity flourish.
   This option suggests humidity as a crucial factor for biodiversity, but it is not commonly accepted as the primary reason for high biodiversity in the tropics.
3. Tropical environments are less seasonal and more constant.
   Lack of seasonality in tropics is thought to promote diverse life forms.
4. There is more solar energy available in the tropics which contributes to higher productivity and biodiversity.
   Availability of solar energy supports biodiversity through increased energy for ecosystems.

Given the explanations, option two is the least aligned with established scientific consensus on the main factors contributing to tropical biodiversity, making it the correct answer: Tropical environments have more humidity/moisture which helps diversity flourish.

Answer 9

(1) Temperate regions are subjected to glaciations, but tropical latitudes have remained relatively undisturbed.

This statement is correct. One hypothesis for the greater biodiversity in the tropics is that temperate regions have experienced glaciations, which can disrupt and reduce biodiversity. In contrast, tropical regions have remained relatively undisturbed, allowing biodiversity to flourish.

(2) Tropical environments have more humidity/moisture which helps the diversity to flourish.

This statement is incorrect. While tropical environments do have more humidity and moisture, which can support high biodiversity, this statement is not a hypothesis explaining the greatest biological diversity in the tropics. Instead, it describes a condition that supports biodiversity.

(3) Tropical environments are less seasonal and more constant.

This statement is correct. One hypothesis for the greater biodiversity in the tropics is that tropical environments are less seasonal and more constant, providing a stable environment for species to thrive.

(4) There is more solar energy available in the tropics which contributes to higher productivity and hence, biodiversity.

This statement is correct. One hypothesis for the greater biodiversity in the tropics is that the higher availability of solar energy leads to higher productivity, which in turn supports a greater variety of species.

Conclusion

The incorrect statement is (2) Tropical environments have more humidity/moisture which helps the diversity to flourish. This statement describes a condition rather than a hypothesis explaining the greatest biological diversity in the tropics.