Question 1 1 / -0
The ____________ constitute the fourth trophic level.
Solution
Each step in a food chain forms a trophic level.
Trophic level I – (Autotrophs or producers) – produce or prepare their own food. For example, plants.
Trophic level II – (Herbivores or primary consumers) – are dependent on plants for their food. For example, deer, rabbit, etc.
Trophic level III – (Small carnivores or secondary consumers) - eat herbivores. For example, snakes, etc.
Trophic level IV – (larger/top carnivores) - eat small carnivores. For example, lions, vultures, etc.
Question 2 1 / -0
From autotrophs, the energy goes to _________ and then finally to __________.
Solution
Autotrophs (for example, plants) prepare their own food, fix solar energy (energy from the sun) and make it available for heterotrophs (which are not capable of preparing their own food and are dependent on autotrophs). Flow of energy is unidirectional and it finally decomposes. When heterotrophs or carnivores die, microbes degrade them and finally consume the energy.
Question 3 1 / -0
A group of interbreeding individuals forms
Solution
A group of interbreeding individuals forms a species. Species can evolve into new species over many generations of successful adaptations.
Question 4 1 / -0
____________ is/are the abiotic component(s) of a pond ecosystem.
Solution
Abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. All non-living components of an ecosystem, such as the atmosphere or water, are called abiotic components.
Question 5 1 / -0
Which of the following substances is not recycled in nature?
Solution
It is a metallic element. It cannot be recycled as residues of it may be considered hazardous waste.
Question 6 1 / -0
Which of the following is not a component of an ecosystem?
Solution
Communities of plants, animals and soil organisms are sometimes referred to as ecosystem. Biome is not a component of an ecosystem. An ecosystem is a part of a biome.
Question 7 1 / -0
The organisms which consume both plant and animal products are known as
Solution
Omnivores eat plants as well as animal products; for example, human beings.
Question 8 1 / -0
____________ is not an example of ecosystem.
Solution
It is a physical component with no biological component. So, it cannot be an example of ecosystem.
Question 9 1 / -0
In which trophic level are herbivores found?
Solution
Trophic level I – (autotrophs or producers) - produce or prepare their own food. For example, plants, etc.
Trophic level II – (herbivores or primary consumers) – are dependent on plants for their food. For example, deer, rabbit, etc.
Trophic level III – (small carnivores or secondary consumers) - eat herbivores. For example, snakes, etc.
Trophic level IV – (larger/top carnivores) - eat small carnivores. For example, lions, vultures, etc.
Question 10 1 / -0
Which of the following ecosystems is natural?
Solution
It is a natural water course in which water is flowing towards an ocean, a lake, a sea or another river.
Question 11 1 / -0
The excessive richness of nutrients in a lake or some other body of water, frequently due to run-off from the land, is called
Solution
Eutrophication is when the environment becomes enriched with nutrients. This can be a problem in marine habitats such as lakes as it can cause algal blooms. Fertilisers are often used in farming. Sometimes, these fertilisers runoff into nearby water, causing an increase in nutrient levels.
Question 12 1 / -0
Organisms in an area interact with the non-living constituents of the environment to form a/an
Solution
The term 'ecosystem' refers to combined physical and biological components of an environment. Soil and sunlight are the physical components of an environment whereas plants are the biological components of an environment.
Question 13 1 / -0
Man belongs to the ____________ category of consumers.
Solution
Man is considered to be an omnivore because he can eat green leafy vegetables as well as flesh.
Question 14 1 / -0
Which of the following organisms can synthesise their food by the process of photosynthesis?
Solution
Algae can synthesise their own food as they are large and diverse groups of simple, autotrophic (which can make their own food) organisms ranging from unicellular to multicellular forms. They are photosynthetic like plants. Each step in a food chain forms a trophic level.
Question 15 1 / -0
The trophic levels represent the steps in a/an
Solution
The trophic level of an organism is the position it occupies in the food chain. The word "trophic" refers to food or feeding.
Question 16 1 / -0
Which of the following are phytoplanktons?
Solution
Phytoplanktons are autotrophic members of the plankton community. They obtain energy through the process of photosynthesis. They are microscopic plant-like organisms that live in the ocean. Small fish and some species of whales eat them.
Question 17 1 / -0
Which of the following is a primary consumer?
Solution
Primary consumers (known as herbivores) belong to the second trophic level and are dependent on the first trophic level called producers (plants). They eat plants. Hence, deer is a primary consumer. Plants cannot be called primary consumers as they are producers, not consumers.
Question 18 1 / -0
In which of the following positions can a tiger be placed in a food chain?
Solution
Tertiary consumers are carnivores which eat flesh. Tiger eats deer (flesh). Therefore, tiger is a tertiary consumer.
Question 19 1 / -0
The lowest level of organisation is
Solution
Atoms
Molecules
Organelle
Cell
Tissues
Organ
Organ system
Organism
Population
Community
Ecosystem
So, the lowest level is atomic level and after that molecular level and so on. Thus, out of the given options, molecular level is the lowest level of organisation.
Question 20 1 / -0
The sequence of living organisms in a community, in which one organism consumes another with the transfer of food energy, is known as
Solution
A food web is a graphical description of feeding relationships (i.e. who eats whom) among species in an ecological community.
Question 21 1 / -0
Which of the following options does not belong to higher level of organisation?
Solution
Molecular level is the smallest level of organisation. Other options belong to higher level of organisation.
Levels of organisation:
Atoms
Molecules
Organelle
Cell
Tissues
Organ
Organ system
Organism
Population
Community
cosystem
Question 22 1 / -0
Which of the following chemicals is/are linked with the depletion of ozone in the atmosphere?
Solution
Chlorofluorocarbons (CFCs) are the organic compounds that contain carbon, chlorine and fluorine. These are commonly known as freons. They contribute to the depletion of ozone, which protects the Earth from harmful UV rays. CFCs are used in refrigeration and air conditioning.
Question 23 1 / -0
Which of the following animals can be a tertiary consumer?
Solution
Lion
Question 24 1 / -0
The plants are placed in the ____ trophic level in a food chain or in an ecological pyramid.
Solution
Trophic Level I – autotrophs or producers – they fix solar energy and make it available for heterotrophs (next trophic level). Therefore, they have been placed in the first trophic level in an ecological pyramid.
Trophic level II – aerbivores or primary consumers – they eat plants.
Trophic level III – small carnivores – they eat herbivores.
Trophic level IV – large carnivores – they eat small carnivores and get energy from them. For example, lion.
Question 25 1 / -0
Which of the following optoions are the the very minute or microscopic organisms freely floating on the surface of water in a pond?
Solution
Plankton are microscopic organisms that float freely with oceanic currents and in other bodies of water. Plankton is made up of tiny plants (called phytoplankton) and tiny animals (called zooplankton).
Question 26 1 / -0
Top carnivores feed upon
Solution
Top carnivores – polar bear, shark, tiger
Small carnivores – snake, spider, eagle
Herbivores– cow, goat, deer
Plants – grass, trees
Zooplanktons – found in fresh water; too small to be seen with naked eye
Top carnivores feed upon small carnivores and herbivores as they cannot eat plants. Zooplanktons and microorganisms are not visible to them as they are too small to be seen with the naked eye.
Question 27 1 / -0
Which of the following options is not represented by an ecological pyramid?
Solution
Body weight is the mass of an organism's body. Body weight is measured in kilograms or pounds. Ecological pyramid does not represent the body weight of each level in the food chain.
Question 28 1 / -0
What is the position of grass in a food chain?
Solution
Grass is an autotroph as it prepares its own food in the presence of sunlight and water. Grass acts as food for herbivores like deer, cattle, etc. Therefore, grass acts as a producer and not as primary carnivore, secondary carnivore and tertiary carnivore.
Question 29 1 / -0
Which of the following statements is true?
Solution
The number of living organisms continuously decreases as we move up in an ecological pyramid.
This is true as an ecological pyramid is represented as follows:
There are generally a large number of producers at lower trophic level of an ecosystem as there is less competition and also, maximum energy is available for use.
Question 30 1 / -0
How many oxygen atoms are present in an ozone molecule?
Solution
Ozone – O3 is a triatomic molecule consisting of three oxygen atoms. It is less stable than diatomic oxygen. Ozone, in lower atmosphere, is an air pollutant with harmful effects. However, the ozone layer, in upper atmosphere, is beneficial in protecting earth from harmful ultraviolet radiations of the sun.
Question 31 1 / -0
What is the type of energy flow in an ecosystem?
Solution
Sun
Producers (green plants)
Members of next trophic level
The energy will never go back to the sun. Therefore, energy flow is unidirectional in an ecosystem.
Question 32 1 / -0
If 15,000 calories of the energy possessed by plants, then how many kilocalories of energy will be transferred to the herbivores?
Solution
1 kilocalorie = 1000 calories
15,000 calories = 15000/1000
= 15 kilocalories
Percentage of energy present at one trophic level and then passed on to the next trophic level = 10
= 1.5 kilocalories
Question 33 1 / -0
Which of the following do not contribute to environmental degradation?
Solution
Pollutants refer to the toxic compounds or wastes coming out from factories, e.g. carbon monoxide, etc, which are harmful to the environment.
Question 34 1 / -0
What percentage of the solar energy fallen on the leaves is utilised by the plants for the process of photosynthesis?
Solution
All living organisms require energy and sun is the ultimate source of energy for every ecosystem. The energy flow of an ecosystem starts when plants capture energy from sunlight and transfer it into glucose that stores energy for later use. In the process of energy transfer from one organism to another, each organism receives only small percentage of total energy, i.e. 10% carried from one trophic level to another and the rest 90% is lost in the environment in form of heat or is egested in faeces or excreted in urine and sweat. For example, if there are 10,000 calories (unit of energy) at one level, then only 1000 calories are transferred to the next level. Approximately, one percent of solar energy that falls on the plants is converted to food.
Question 35 1 / -0
When the trophic level in an ecological pyramid increases, the number of living organisms
Solution
This is true as ecological pyramid is represented as follows:
Question 36 1 / -0
What percentage of energy present at one trophic level is passed on to the next trophic level?
Solution
The green plants in a terrestrial ecosystem capture about 1% of the energy of sunlight that falls on their leaves and convert it into food energy.
Question 37 1 / -0
Which of the following statements is not inferred from the ecological pyramid?
Solution
Ecological pyramid represents loss in energy, loss in number of individuals and loss in biomass at each trophic level from bottom to top. But, it does not represent loss of weight at each trophic level.
Question 38 1 / -0
____________ is/are the ultimate source of energy.
Solution
Nuclear fusion reactions are the source of energy in the sun. The sun produces 99% of energy through fusion. It takes high amount of force to fuse the nuclei. Therefore, high temperature and pressure is required for the process to take place (The temperature at the centre of the sun is 15 million Kelvin.)
Question 39 1 / -0
The ozone layer protects Earth from the ____________ of the sun.
Solution
Ozone (O3 ) is a molecule formed by three atoms of oxygen. Ozone is a deadly poison. However, at higher levels of atmosphere, ozone performs an essential function. It shields the surface of Earth from ultraviolet (UV) radiations of the sun.
Question 40 1 / -0
The ____________ fix up the solar energy and make it available in a food chain.
Solution
Producers are green plants (autotrophs), which make their own food in the presence of sunlight by the process of photosynthesis. They capture the energy present in sunlight and convert it into chemical energy. This energy supports all the activities of living world. From autotrophs, the energy goes to the next member of the food chain.
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