Textbook Question
According to the island equilibrium model, species richness would be greatest on an island that is
a. Large and remote
b. Small and remote
c. Large and close to a mainland
d. Small and close to a mainland
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Ch. 54 - Community Ecology
Urry11th EditionCampbell BiologyISBN: 9789357423311
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Table of contents
- Ch. 1 - Evolution, the Themes of Biology, and Scientific Inquiry8
- Ch. 2 - The Chemical Context of Life8
- Ch. 3 - Water and Life6
- Ch. 4 - Carbon and the Molecular Diversity of Life9
- Ch. 5 - The Structure and Function of Large Biological Molecules9
- Ch. 6 - A Tour of the Cell6
- Ch. 7 - Membrane Structure and Function6
- Ch. 8 - An Introduction to Metabolism6
- Ch. 9 - Cellular Respiration and Fermentation10
- Ch. 10 - Photosynthesis7
- Ch. 11 - Cell Communication7
- Ch. 12 - The Cell Cycle10
- Ch. 13 - Meiosis and Sexual Life Cycles10
- Ch. 14 - Mendel and the Gene Idea14
- Ch, 15 - The Chromosomal Basis of Inheritance7
- Ch. 16 - The Molecular Basis of Inheritance9
- Ch. 17 - Gene Expression: From Gene to Protein9
- Ch. 18 - Regulation of Gene Expression10
- Ch. 19 - Viruses6
- Ch. 20 - DNA Tools and Biotechnology8
- Ch. 21 - Genomes and Their Evolution8
- Ch. 22 - Descent with Modification: A Darwininan View of Life6
- Ch. 23 - The Evolution of Populations5
- Ch. 24 - The Origin of Species6
- Ch. 25 - The History of Life on Earth6
- Ch. 26 - Phylogeny and the Tree of Life7
- Ch. 27 - Bacteria and Archaea8
- Ch. 28 - Protists7
- Ch. 29 - Plant Diversity I: How Plants Colonized Land7
- Ch. 30 - Plant Diversity II: The Evolution of Seed Plants7
- Ch. 31 - Fungi5
- Ch. 32 - An Overview of Animal Diversity4
- Ch. 33 - An introduction to Invertebrates6
- Ch. 34 - The Origin and Evolution of Vertebrates7
- Ch. 35 - Vascular Plant Structure, Growth, and Development8
- Ch. 36 - Resource Acquisition and Transport in Vascular Plants8
- Ch. 37 - Soil and Plant Nutrition10
- Ch. 38 - Angiosperm Reproduction and Biotechnology8
- Ch. 39 - Plant Responses to Internal and External Signals8
- Ch. 40 - Basic Principles of Animal Form and Function8
- Ch. 41 - Animal Nutrition7
- Ch. 42 - Circulation and Gas Exchange7
- Ch. 43 - The Immune System6
- Ch. 44 - Osmoregulation and Excretion6
- Ch. 45 - Hormones and the Endocrine System8
- Ch. 46 - Animal Reproduction8
- Ch. 47 - Animal Development8
- Ch. 48 - Neurons, Synapses, and Signaling6
- Ch. 49 - Nervous Systems8
- Ch. 50 - Sensory and Motor Mechanisms5
- Ch. 51 Animal Behavior6
- Ch. 52 - An Introduction to Ecology and the Biosphere7
- Ch. 53 - Population Ecology10
- Ch. 54 - Community Ecology9
- Ch. 55 - Ecosystems and Restoration Ecology8
- Ch. 56 - Conservation Biology and Global Change6
Chapter 54, Problem 7
Which of the following could qualify as a top-down control on a grassland community?
a. Limitation of plant biomass by rainfall amount
b. Influence of temperature on competition among plants
c. Influence of soil nutrients on the abundance of grasses versus wildflowers
d. Effect of grazing intensity by bison on plant species diversity
Verified step by step guidance1
Understand the concept of top-down control: In ecology, top-down control refers to the influence of predators or consumers on the structure and dynamics of ecosystems. It contrasts with bottom-up control, which is driven by resource availability such as nutrients or sunlight.
Analyze each option to determine if it represents a top-down control: Top-down control typically involves the impact of higher trophic levels (like predators or herbivores) on lower trophic levels (like plants).
Evaluate option a: Limitation of plant biomass by rainfall amount is a bottom-up control because it involves abiotic factors affecting plant growth.
Evaluate option b: Influence of temperature on competition among plants is also a bottom-up control, as it involves abiotic factors affecting plant interactions.
Evaluate option d: Effect of grazing intensity by bison on plant species diversity is a top-down control, as it involves herbivores (bison) affecting the diversity and composition of plant species in the grassland community.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Top-Down Control
Top-down control refers to the influence of higher trophic levels on the structure and dynamics of ecosystems. In a grassland community, this could involve predators or herbivores affecting the abundance and diversity of plant species. For example, grazing by bison can regulate plant species diversity by selectively feeding on certain plants, thereby shaping the community composition.
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05:06
Bottom-Up & Top-Down Effects on Community Structure
Trophic Levels
Trophic levels are the hierarchical levels in an ecosystem, comprising producers, consumers, and decomposers. Each level represents a step in the food chain, with energy and nutrients flowing from one level to the next. Understanding trophic levels is crucial for identifying how top-down controls, such as herbivory, can impact lower levels like plant communities in grasslands.
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03:14Trophic Structure
Community Dynamics
Community dynamics involve the interactions and changes within an ecological community over time. Factors such as predation, competition, and environmental conditions can influence these dynamics. In the context of the question, grazing intensity by bison represents a biotic factor that can alter plant species diversity, demonstrating a top-down control mechanism in the grassland ecosystem.
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03:01Community Dynamics Example 1
Related Practice
Textbook Question
Predators that are keystone species can maintain species diversity in a community if they
a. Competitively exclude other predators
b. Prey on the community's dominant species
c. Reduce the number of disruptions in the community
d. Prey only on the least abundant species in the community
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Textbook Question
Food chains are sometimes short because
a. Only a single species of herbivore feeds on each plant species.
b. Local extinction of a species causes extinction of the other species in its food chain.
c. Most of the energy in a trophic level is lost as energy passes to the next higher level.
d. Most producers are inedible.
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Textbook Question
The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that
a. Tropical communities are younger.
b. Tropical regions generally have more available water and higher levels of solar radiation.
c. Higher temperatures cause more rapid speciation.
d. Diversity increases as evapotranspiration decreases.
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Textbook Question
Community 1 contains 100 individuals distributed among four species: 5A, 5B, 85C, and 5D. Community 2 contains 100 individuals distributed among three species: 30A, 40B, and 30C. Calculate the Shannon diversity (H) for each community. Which community is more diverse?
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