ECOSYSTEM
FILL IN THE BLANKS
Q.01: Fill in the blanks:
(i) A group of similar organisms living together in space and time is called _______. (population)
(ii) Organisms which can synthesize their own food are called _______. (producers)
(iii) Animals, non-green plants and microorganisms directly or indirectly depend upon green plants for their food so they so are called _______. (consumers)
TRUE / FALSE
Q.02: Indicate True or False:
(i) At different places in an environment when you study only one population, it will be synecology. (FALSE)
CORRECT: At different places in an environment when you study only one population, it will be autecology.
(ii) Abiotic components include all living components. (FALSE)
CORRECT: Abiotic components include all non-living components.
(iii) Primary succession starting in a pond is called xerosere. (FALSE)
CORRECT: Primary succession starting in a pond is called hydrosere.
(iv) The animal that is caught and eaten is the predator. (FALSE)
CORRECT: The animal that is caught and eaten is the prey.
(v) Endoparasites live inside the body of the host. (TRUE)
MCQs
Q.03: Each questiuon has four possible options. Encircle the correct answer.
(i) The study of relationship of an organism to their environment is known as:
(a) Biology
(b) Ecology
(c) Zoology
(d) Mycology
ANSWER: (b) Ecology
EXPLANATION: Ecology is the scientific study of how organisms interact with each other and their environment, examining the relationships, adaptations, and dynamics within ecosystems. It explores the interconnected web of life and the impact of environmental factors on living organisms.
(ii) Similarly, group of individuals who can interbreed and produce organisms of their own kind forms a:
(a) Population
(b) Community
(c) Species
(d) Succession
ANSWER: (c) Species
EXPLANATION: A species is a group of organisms that can interbreed and produce fertile offspring, sharing common characteristics and forming a distinct unit in the biological classification.
(iii) When living and non-living interact to produce a stable system in which exchange of material with flow of energy takes place it forms a /an:
(a) Environment
(b) Ecosystem
(c) Stable community
(d) Ecological succession
ANSWER: (b) Ecosystem
EXPLANATION: An ecosystem is a dynamic system where living organisms interact with their non-living environment, creating a balanced and self-sustaining community. Within this system, there is a continuous exchange of materials and energy, ensuring the stability of the ecological unit.
(iv) The living organism which can prepare their own food are:
(a) Predators
(b) Parasites
(c) Producers
(d) Prey
ANSWER: (c) Producers
EXPLANATION: Producers in an ecosystem are organisms, mainly plants and some bacteria, that convert sunlight into energy through photosynthesis, forming the foundational source of nutrition for the entire food chain. They play a crucial role in capturing and transforming solar energy into organic compounds.
(v) The living organism which cannot prepare their own food but obtain ready-made food from others are:
(a) Primary and secondary consumers
(b) Only primary consumers
(c) Secondary and tertiary consumers
(d) Consumers
ANSWER: (d) Consumers
EXPLANATION: Consumers in an ecosystem are organisms, including animals, that obtain energy by consuming other living organisms. They play a vital role in the food chain, transferring energy through different trophic levels.
Q.04: SHORT QUESTIONS
(i) What are the biogeochemical cycles?
ANSWER:
Biogeochemical Cycles:
“Biogeochemical cycles are natural processes that involve the movement of essential elements like carbon, nitrogen, and water between living organisms, the atmosphere, soil, and rocks, ensuring the recycling and availability of these elements within ecosystems.” These cycles play a crucial role in maintaining environmental balance.
Example: Nitrogen cycle.
(ii) Sketch three main steps in nitrogen cycle.
ANSWER:
(iii) Define grazing.
ANSWER:
Grazing:
“Many animals like rabbits, goats, sheep, cows, buffaloes and horses feed on grasses. This mode of feeding is called grazing and these animals are called grazers.”
(iv) What percentage of sun energy reaches to plants?
ANSWER:
About 1% of the total energy from the sun is trapped by the producers in an ecosystem. The remaining 99% of solar energy is used to evaporate water, heat up soil and is then lost to the outer space.
(v) What is autecology?
ANSWER:
Autecology:
“The study of a single population’s relationship to its environment is called autecology.”
For example, you are studying 50 to 100 plants of soybean in order to know the effect of water pollution on their growth and yield, you are studying the single or one population of soybean plant, this study is autecology.
(vi) Define synecology.
ANSWER:
Synecology:
“The study of the relationship of different communities (grouping of populations) to their environment is called synecology or community ecology.”
In synecology, all the populations in a community are studied, including different aspects such as the origin, structure and composition of the community.
Q.05: EXTENSIVE QUESTIONS
(i) Define environment. What must environment supply for insects, green plants, birds, animals and people?
ANSWER:
Environment:
“Environment is the physical as well as biological conditions under which an organism lives.”
For insects, green plants, birds, animals, and people, the environment must provide appropriate living conditions, including habitats, food sources, and the necessary resources for their survival and well-being.
(ii) What factors in the environment can affect all living things? Are they important to survive in a biome?
ANSWER:
Factors Affecting Livings Things in Environment:
Living things on Earth face a multitude of environmental factors that impact their survival and well-being. These factors can be broadly categorized into two main groups:
1. ABIOTIC FACTORS:
These are non-living components of the environment and play a crucial role in an organism’s existence. Some key abiotic factors include:
i) Temperature: Affects physiological processes like growth, development, and reproduction. For instance, warm-blooded animals require specific temperature ranges to maintain internal body temperature.
ii) Light: Crucial for photosynthesis in plants and influences various animal behaviors like hunting, migration, and reproduction.
iii) Water: Essential for all living things, impacting everything from cellular functions to survival in arid environments.
iv) Air: Composed of various gases like oxygen, necessary for cellular respiration in most organisms.
v) Soil: Provides nutrients and anchorage for plants and influences the survival of organisms living within it.
2. BIOTIC FACTORS:
These are living components of the environment and involve interactions between organisms. They include:
i) Food availability: The presence and quantity of food sources directly impact an organism’s survival and growth.
ii) Predation: The presence of predators and the risk of being preyed upon influence an organism’s behavior and adaptations.
iii) Competition: Competition for resources like food, water, and space between individuals or species can shape an organism’s survival strategies.
iv) Symbiotic relationships: Mutualistic, parasitic, and commensalistic relationships between different species can significantly impact their survival and reproduction.
IMPORTANCE IN BIOMES:
These factors are essential for survival within a biome, which is a specific geographic region characterized by distinct abiotic and biotic factors. The unique combination of these factors in a biome determines the types of organisms that can thrive within it.
(iii) What can you conclude about all the physical and biological factors in an environment?
ANSWER:
Factors Affecting Livings Things in Environment:
Living things on Earth face a multitude of environmental factors that impact their survival and well-being. These factors can be broadly categorized into two main groups:
1. ABIOTIC FACTORS:
These are non-living components of the environment and play a crucial role in an organism’s existence. Some key abiotic factors include:
i) Temperature: Affects physiological processes like growth, development, and reproduction. For instance, warm-blooded animals require specific temperature ranges to maintain internal body temperature.
ii) Light: Crucial for photosynthesis in plants and influences various animal behaviors like hunting, migration, and reproduction.
iii) Water: Essential for all living things, impacting everything from cellular functions to survival in arid environments.
iv) Air: Composed of various gases like oxygen, necessary for cellular respiration in most organisms.
v) Soil: Provides nutrients and anchorage for plants and influences the survival of organisms living within it.
2. BIOTIC FACTORS:
These are living components of the environment and involve interactions between organisms. They include:
i) Food availability: The presence and quantity of food sources directly impact an organism’s survival and growth.
ii) Predation: The presence of predators and the risk of being preyed upon influence an organism’s behavior and adaptations.
iii) Competition: Competition for resources like food, water, and space between individuals or species can shape an organism’s survival strategies.
iv) Symbiotic relationships: Mutualistic, parasitic, and commensalistic relationships between different species can significantly impact their survival and reproduction.
IMPORTANCE IN BIOMES:
These factors are essential for survival within a biome, which is a specific geographic region characterized by distinct abiotic and biotic factors. The unique combination of these factors in a biome determines the types of organisms that can thrive within it.
(iv) What is biosphere? What must the biosphere provide for living things? Why is a biosphere absent on moon?
ANSWER:
Biosphere:
“The biosphere refers to the region of the Earth where life exists, encompassing the surface, atmosphere, and hydrosphere. It includes all living organisms and their interactions with the physical environment.”
The biosphere must provide essential conditions for living things, including a range of temperatures suitable for life, availability of water, access to nutrients, and a hospitable atmosphere. Additionally, the biosphere must support ecological processes like nutrient cycling and energy flow.
A biosphere is absent on the Moon because it lacks the necessary conditions to sustain life. The Moon has extreme temperature variations, no atmosphere, and no liquid water, making it inhospitable for living organisms. Unlike Earth, the Moon does not possess the complex environmental factors required to support the diverse and interconnected web of life found in the biosphere.
(v) Define succession. Discuss succession on land.
ANSWER:
Consult textbook at page 240 — 242.
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