Q. In a food chain, which of the following is the primary producer? (2019)
A.
Herbivores
B.
Carnivores
C.
Plants
D.
Decomposers
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Solution
Primary producers are organisms that produce their own food, primarily plants through photosynthesis.
Correct Answer:
C
— Plants
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Q. In a predator-prey relationship, what is the primary effect of an increase in the prey population? (2021)
A.
Decrease in predator population
B.
Increase in predator population
C.
Decrease in prey population
D.
No effect on predator population
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Solution
An increase in the prey population typically leads to an increase in the predator population due to more available food.
Correct Answer:
B
— Increase in predator population
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Q. In a predator-prey relationship, which of the following is true? (2022)
A.
Predators are always larger than their prey.
B.
Prey populations are always larger than predator populations.
C.
Predators help control prey populations.
D.
Prey can never escape predators.
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Solution
Predators help control the population of prey species, maintaining a balance in the ecosystem.
Correct Answer:
C
— Predators help control prey populations.
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Q. In ecological succession, what is the term for the first species to colonize a barren environment? (2022)
A.
Pioneer species
B.
Climax community
C.
Keystone species
D.
Invasive species
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Solution
Pioneer species are the first organisms to colonize previously uninhabited or disturbed environments.
Correct Answer:
A
— Pioneer species
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Q. In which type of interaction do both species benefit? (2023)
A.
Predation
B.
Competition
C.
Mutualism
D.
Parasitism
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Solution
Mutualism is an interaction where both species involved benefit from the relationship.
Correct Answer:
C
— Mutualism
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Q. In which type of population distribution do individuals have a uniform distance between them? (2019)
A.
Random
B.
Clumped
C.
Uniform
D.
None of the above
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Solution
Uniform distribution occurs when individuals are evenly spaced, often due to competition for resources.
Correct Answer:
C
— Uniform
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Q. In which type of population growth does the growth rate decrease as the population reaches its carrying capacity? (2019)
A.
Exponential growth
B.
Logistic growth
C.
Linear growth
D.
Cyclic growth
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Solution
Logistic growth describes a population that grows rapidly at first and then slows as it approaches the carrying capacity.
Correct Answer:
B
— Logistic growth
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Q. What is carrying capacity? (2021)
A.
The maximum number of individuals an environment can support
B.
The minimum number of individuals needed for a population to survive
C.
The average number of individuals in a population
D.
The number of species in a community
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Solution
Carrying capacity is the maximum number of individuals of a species that an environment can sustainably support.
Correct Answer:
A
— The maximum number of individuals an environment can support
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Q. What is the primary characteristic of a K-selected species? (2023)
A.
High reproductive rate
B.
Short lifespan
C.
High parental care
D.
Rapid growth
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Solution
K-selected species typically exhibit high parental care and invest more resources in fewer offspring.
Correct Answer:
C
— High parental care
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Q. What is the primary factor that determines the distribution of organisms in an ecosystem? (2020)
A.
Soil type
B.
Climate
C.
Topography
D.
Human activity
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Solution
Climate is the primary factor influencing the distribution of organisms, as it affects temperature, precipitation, and seasonal changes.
Correct Answer:
B
— Climate
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Q. What is the primary reason for the increase in human population over the last century? (2023)
A.
Increased birth rates
B.
Decreased death rates
C.
Improved healthcare
D.
All of the above
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Solution
The increase in human population is attributed to a combination of increased birth rates, decreased death rates, and improved healthcare.
Correct Answer:
D
— All of the above
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Q. What is the primary source of energy for most ecosystems? (2020)
A.
Geothermal energy
B.
Wind energy
C.
Solar energy
D.
Nuclear energy
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Solution
Solar energy is the primary source of energy for most ecosystems, driving photosynthesis in plants.
Correct Answer:
C
— Solar energy
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Q. What is the term for the gradual change in species composition in a given area over time? (2023)
A.
Succession
B.
Evolution
C.
Adaptation
D.
Migration
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Solution
Succession refers to the process of change in the species structure of an ecological community over time.
Correct Answer:
A
— Succession
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Q. What is the term for the gradual process of change and replacement in the species composition of a given area? (2022)
A.
Succession
B.
Evolution
C.
Adaptation
D.
Migration
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Solution
Succession is the process of change in the species structure of an ecological community over time.
Correct Answer:
A
— Succession
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Q. What is the term for the gradual process of change in species composition in a given area over time? (2019)
A.
Succession
B.
Evolution
C.
Adaptation
D.
Migration
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Solution
Succession refers to the process of change in the species structure of an ecological community over time.
Correct Answer:
A
— Succession
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Q. What term describes the role and position a species has in its environment? (2020)
A.
Habitat
B.
Niche
C.
Biome
D.
Ecosystem
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Solution
The niche of a species is its role and position in its environment, including all interactions with biotic and abiotic factors.
Correct Answer:
B
— Niche
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Q. What term describes the role of an organism in its environment? (2019)
A.
Habitat
B.
Niche
C.
Biome
D.
Community
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Solution
The niche of an organism refers to its role and position in its environment, including all interactions with biotic and abiotic factors.
Correct Answer:
B
— Niche
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Q. What type of interaction occurs when one organism benefits while the other is harmed? (2021)
A.
Mutualism
B.
Commensalism
C.
Parasitism
D.
Competition
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Solution
Parasitism is a type of interaction where one organism benefits at the expense of another.
Correct Answer:
C
— Parasitism
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Q. What type of interaction occurs when two species compete for the same resources? (2021)
A.
Mutualism
B.
Commensalism
C.
Competition
D.
Predation
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Solution
Competition occurs when two species vie for the same limited resources, which can negatively impact both species.
Correct Answer:
C
— Competition
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Q. Which of the following best describes a climax community? (2018)
A.
A community that is in a state of constant change.
B.
A stable community that has reached a steady state.
C.
A community that is dominated by pioneer species.
D.
A community that is always changing due to disturbances.
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Solution
A climax community is a stable and mature ecological community that has reached a steady state.
Correct Answer:
B
— A stable community that has reached a steady state.
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Q. Which of the following best describes a population? (2020)
A.
All organisms in a biome
B.
All individuals of a species in a given area
C.
All living organisms in an ecosystem
D.
All species in a community
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Solution
A population is defined as all individuals of a particular species that live in a specific area.
Correct Answer:
B
— All individuals of a species in a given area
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Q. Which of the following best describes the term 'carrying capacity'? (2020)
A.
The maximum population size that an environment can sustain
B.
The minimum population size for survival
C.
The average population size over time
D.
The population size at which birth rates equal death rates
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Solution
Carrying capacity refers to the maximum population size that an environment can sustainably support.
Correct Answer:
A
— The maximum population size that an environment can sustain
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Q. Which of the following factors is considered an abiotic factor? (2019)
A.
Fungi
B.
Bacteria
C.
Sunlight
D.
Plants
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Solution
Abiotic factors are non-living chemical and physical components of the environment, such as sunlight, temperature, and water.
Correct Answer:
C
— Sunlight
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Q. Which of the following is a biotic factor in an ecosystem? (2020)
A.
Temperature
B.
Soil pH
C.
Plants
D.
Water availability
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Solution
Biotic factors are the living components of an ecosystem, which include plants, animals, and microorganisms.
Correct Answer:
C
— Plants
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Q. Which of the following is a density-dependent factor affecting population growth? (2019)
A.
Natural disasters
B.
Food availability
C.
Climate
D.
Habitat destruction
Show solution
Solution
Food availability is a density-dependent factor because its effect on population growth changes with population density.
Correct Answer:
B
— Food availability
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Q. Which of the following is a primary producer in an ecosystem? (2022)
A.
Herbivores
B.
Carnivores
C.
Plants
D.
Decomposers
Show solution
Solution
Primary producers, such as plants, convert solar energy into chemical energy through photosynthesis.
Correct Answer:
C
— Plants
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Q. Which of the following is an abiotic factor in an ecosystem? (2019)
A.
Fungi
B.
Bacteria
C.
Temperature
D.
Plants
Show solution
Solution
Abiotic factors are the non-living physical and chemical components of an ecosystem, such as temperature.
Correct Answer:
C
— Temperature
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Q. Which of the following is an example of a biotic factor in an ecosystem? (2022)
A.
Soil pH
B.
Temperature
C.
Plants
D.
Water availability
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Solution
Plants are a biotic factor as they are living organisms that interact with other organisms in the ecosystem.
Correct Answer:
C
— Plants
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Q. Which of the following is an example of a density-dependent factor affecting population growth? (2021)
A.
Natural disasters
B.
Disease
C.
Climate change
D.
Habitat destruction
Show solution
Solution
Density-dependent factors, such as disease, have a greater effect as the population density increases.
Correct Answer:
B
— Disease
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Q. Which of the following is an example of a mutualistic relationship? (2023)
A.
Bees pollinating flowers
B.
Lions hunting zebras
C.
Moss growing on a tree
D.
Birds nesting in trees
Show solution
Solution
Bees pollinating flowers is a mutualistic relationship where both species benefit from the interaction.
Correct Answer:
A
— Bees pollinating flowers
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Showing 1 to 30 of 35 (2 Pages)
Ecology - Organisms & Populations MCQ & Objective Questions
Understanding "Ecology - Organisms & Populations" is crucial for students preparing for school and competitive exams in India. This topic not only forms a significant part of the syllabus but also helps in developing a deeper understanding of ecological relationships and population dynamics. Practicing MCQs and objective questions on this subject can significantly enhance your exam preparation, allowing you to identify important questions and improve your scoring potential.
What You Will Practise Here
Key concepts of ecology and the role of organisms in ecosystems.
Population dynamics, including growth models and factors affecting population size.
Interactions among species, such as predation, competition, and symbiosis.
Ecological succession and its stages.
Biogeochemical cycles and their importance in ecosystems.
Definitions of important terms like carrying capacity, niche, and habitat.
Diagrams illustrating food webs, energy flow, and population pyramids.
Exam Relevance
This topic is frequently featured in CBSE, State Boards, NEET, and JEE exams. Students can expect questions that test their understanding of ecological principles, population characteristics, and the interactions between organisms and their environment. Common question patterns include multiple-choice questions that require application of concepts, as well as scenario-based questions that assess critical thinking and problem-solving skills.
Common Mistakes Students Make
Confusing the terms "population" and "community".
Misunderstanding the different types of species interactions.
Overlooking the significance of abiotic factors in ecosystems.
Failing to apply the concepts of carrying capacity and limiting factors in population studies.
FAQs
Question: What are the main factors that affect population growth?Answer: The main factors include birth rate, death rate, immigration, and emigration.
Question: How does energy flow in an ecosystem?Answer: Energy flows through an ecosystem in a one-way stream, from primary producers to various levels of consumers.
Now is the time to strengthen your understanding of "Ecology - Organisms & Populations". Dive into our practice MCQs and test your knowledge to excel in your exams!