Solutions of Our Environment Lakhmir Singh Manjit Kaur VSAQ, and SAQ Pg No. 226 Class 10 Biology
1. What is the functional unit of the environment comprising of the living and non-living components called?
Answer
→ The functional unit of the environment comprising of the living and non-living components is called ‘Ecosystem’.
Ecosystem includes all the living things (plants, animals) in an area interacting with each other and with their non-living environment (weather, soil, etc.) too
2. Name two natural ecosystems and two artificial Ecosystems.
Answer
→ ●Natural Ecosystem are Grassland Ecosystem and forest ecosystem; Grassland and forest are naturally created and interaction among the living and non-living things is common here. Natural ecosystem have no interference of human beings.
●Artificial ecosystem- Parks, garden, Aquariums. Artificial ecosystems are man-made ecosystem so man creates parks, gardens, aquariums where organisms interact with living and non-living components, For example- Aquarium is created by man where fishes are put inside and they are given necessary things for them to survive.
3. Which one of the following is not a terrestrial ecosystem?
Forest, Grassland, Aquarium, Desert
Answer
→ Aquarium is not a terrestrial ecosystem because terrestrial ecosystems are found only on landforms and aquarium exists in water and is an example of man-made ecosystem. Thus, forest, grassland, and desert are terrestrial ecosystems whereas aquarium is an artificial ecosystem.
4. Why are plants called producers?
Answer
→ Plants are called producers because they produce their own food through the process of photosynthesis where they utilize sunlight, carbon dioxide, water, chlorophyll to produce nutrients and release oxygen as a by-product.
5. What name has been given to those organisms which break down the complex organic compounds present in dead animals and plants?
Answer
→ Organisms that break down the complex organic compounds present in dead animals and plants are known as Decomposers. Decomposers break down the complex organic compounds in dead animals and plants to obtain nutrients from the dead and decaying matter. For example – bacteria and fungi are decomposers.
6. What are planktons?
Answer
→ Planktons are minute organisms that live in the water but are incapable of swimming against a current. They are a source of food to aquatic organisms like fishes.
7. State whether the following statements are true or false:
(a) In biology, human beings are called producers.
(b) Secondary consumers and tertiary consumers, both are carnivores.
Answer
→ a) False. Plants are called producers because they make their own food as they have autotrophic mode of nutrition. Human beings obtain the food made by plants and other organisms because they follow hetrotrophic mode of nutrition.
b) True. Secondary consumers eat primary consumers. They are carnivores i.e. they eat flesh and also omnivores. Tertiary consumers are at the top in a food chain and they feed on secondary consumers. Tertiary consumers are also carnivores.
8. Which category of organisms forms the starting point of a food chain?
Answer
→ Producers form the starting point of a food chain. Producers are autotrophic and they produce their own food through photosynthesis.
9. Which of the following belong to the same trophic level?
Goat; Spider; Plants; Hawk; Rat
Answer
Goat and Rat belong to the same trophic level. They belong to Herbivores as they feed on plants
10. Which of the following belong to the same trophic level?
Tree; Frog ; Snake ; Grass ; Lizard
Answer
→ Tree and Grass belong to the same trophic level. They belong to producers as they are plants i.e. they contain chlorophyll which is required to perform photosynthesis in the presence of sunlight, water, and carbon dioxide.
11. Write an aquatic food chain.
Answer
→ An aquatic food chain begins with phytoplankton like algae which are producers, these phytoplankton are eaten by zooplankton like protozoan (primary consumer). The primary consumers are eaten by secondary consumers which are small fishes in an aquatic food chain. These secondary consumers (fishes) are eaten by large fishes which are tertiary consumers. The tertiary consumers are further eaten by quaternary consumers, usually whale in an aquatic food chain. (Secondary, tertiary, and quaternary consumers are also known as carnivores).
12. Name the organisms belonging to the second and the fourth trophic levels in the food chain comprising the following:
Frogs, Plants, Snakes, Hawk, Insects.
Answer
→ Second trophich level in a food chain is Primary consumer. Primary consumers eat or feed on producers which ar eplants. Insects belong to the secondary trophich level i.e. they are primary consumers.
The fourth trophic level in a food chain is Tertiary consumers or carnivores. Snakes belong to the fourth tropic level.
13. What are the various steps of food chain called?
Answer
→ The various steps of food chain are called trophic level. A trophic level is a position that an organism occupies in a food chain.
14. Construct a food chain comprising the following: Snakes, Hawk, Rats and plant.
Answer
15. Arrange the following in a food chain: Fish, Algae, Small animals, Big Fish
Answer
→ The following is an example of aquatic food chain.
16. Which organisms belong to third and fourth trophic levels in the food chain comprising the following?
Rats, Plants, Hawk, Snakes
Answer
→ Third trophic level- Snakes (tertiary consumer) belong to the third trophic level.
Fourth tropic level- Hawk (quaternary consumer) belongs to the fourth trophic level.
17. Which one term in the following includes the others?
Air, flora, fauna, environment, water, sunlight, soil
Answer
→ Environment is the term which includes air, flora, fauna, water, sunlight and soil.
Environment is defined as the geographical surrounding in which an organism (plants, animals, human) lives. Air, flora (plants), fauna (animals) water, sunlight and soil; all are components of the environment.
18. A food chain represents a unidirectional flow of X. What is X?
Answer
→ Unidirectional flow of X represents flow of energy in a food chain. Energy is transferred via trophic levels from producers to carnivores. The energy enters the plants from sun during photosynthesis. This energy is further passed on from one organism to another in the food chain .
19. Fill in the following blanks with suitable words:
(a) Decomposer organisms are................in their action.
(b) In nature, all green plants are..................... whereas animals are consumers.
(c) A series of organisms, each of which feeds on the next organism, the beginning of which is a green plant, is called a..................
(d) The science that deals with the inter-relationships of living things with one another and their environment is called....................
(e) Plastic is a ......................material whereas paper is a..................material.
Answer
→ a) Specific;
Decomposers (like bacteria and fungi) work only on dead and decaying matter to obtain nutrients from them.
b) Producer;
Green plants have chlorophyll and they use energy from sun, water and carbon dioxide to make their own food, so they are called producers. Animals are consumers because they cannot make their own food. They either eat plants or other animals.
c) Food chain;
Food chain can be defined as a series of organisms where each organism is dependent on the next for food.
d) Ecology;
Ecology is the study of how organisms interact with each other and their environment.
e) Non-biodegradable; biodegradable.
Plastic is non-biodegradable because it is rarely consumed by bacteria so they do not decompose. Whereas, paper is biodegradable because paper is made of plant material and plant materials are biodegradable.
Short Answer Type Questions-Pg-226
20. Explain the terms 'producer' and 'consumer'. Give two examples of producers and two of consumers.
Answer
→ Producers are defined as organisms that prepare their own food using inorganic substances like water, carbon dioxide in the presence of chlorophyll and sunlight, and they release oxygen as a by-product. For example- green plants, blue algae, lichens etc. are producers , they make their own food by the process of photosynthesis.
Consumers are organisms that cannot make their own food and so they depend on producers for food. For example- Lion, Bears, Tiger are consumers.
21A. Define decomposers. Name one decomposer.
Answer
→ (A) Decomposers are organism that breakdown the organic components of dead and decaying matter (plants and animals) into simpler substances and feeds on them. Decomposers are usually microorganisms like bacteria and fungi which obtain their nutrients from dead and decaying matter.
21B. What is the role of decomposers in the ecosystem?
Answer
→ (B) Decomposers play a vital role in the ecosystem as they breakdown the organic components of dead and decaying matter into simpler substances. The organic matter is recycled in the ecosystem thus acting as cleansing agent for the environment.
22. What is meant by a primary consumer, secondary consumer and a tertiary consumer? Give one example of each.
Answer
→ ●Primary consumer- Primary consumers are living organisms that only eat plants i.e. producers. Herbivores/ plant eaters are primary consumers. For example- Goat, Rabbit.
●Secondary consumer- Secondary consumers are organisms that eat herbivores/ primary consumers for their food/ nutrient requirements. They are known as carnivores that feed on herbivores. For example- Frog, rat etc.
●Tertiary consumer- tertiary consumers are organisms that feed on secondary consumers. Basically, tertiary consumers are large carnivores which feed on small carnivores. For example- Owl, lion, etc.
23. Give an example of a four step food chain operating in grassland. Name the secondary consumer in this food chain.
Answer
→ Example of a food chain operating in grassland
24A. Define trophic level. Draw the food chain with four trophic levels.
Answer
→ (A)
Trophic level is the steps in a food chain where transfer of food in the form of energy takes place between organisms. At each step in a food chain is an organism that forms the trophic level.
A food chain consisting of four trophic levels.
24B. What will happen if we kill all the organisms in one trophic level?
Answer
→ (B)
If all the organisms in one trophic level are killed then the transfer of energy to the next trophic level will stop. Also it will cause over population at one of the trophic level whose predators will be killed. Thus, disturbing the food chain completely.
25. What is the difference between the food habits of organisms belonging to the first and the third trophic levels? Give one example each of the organisms belonging to these two trophic levels.
Answer
→ The organisms at first trophic level in a food chain are producers, always. They are autotrophs, they make their own food. For example- Plants are producers
The organisms at third trophic level in a food chain are consumers. They are carnivores at third trophic level. They feed on herbivorous animals. For example frog feeds on insects.
26. Can the organisms of any trophic level be removed without causing any damage to the ecosystem? Will the impact of removing all the organisms in a trophic level be different for different trophic levels?
Answer
→ No; If organisms from any trophic level are removed, the ecosystem may collapse because it will disturb the food chain completely. There will be no transfer of energy to the next trophic level and a population of organisms, whose predators will be removed, will increase in number; thus disturbing the entire food chain and causing a great damage to the ecosystem.
Yes the impact will be different for different trophic levels. The organisms whose predators will be removed from the trophic level will increase drastically in number. The organisms whose prey will be removed will not receive energy and nutrients and thus start to disappear.
For example, Plant—Insect—Frog—Snake.
Suppose if frogs are removed, the insects will increase in number because there predators are removed. The snakes would die of starvation as their prey i.e. frogs will be removed from the trophic level.
27. Consider the food chain:
Grass Deer Lion
What will happen if all the lions are removed from the above food chain?
Answer
→ If all the lions are removed from the given food chain, the number of deer will increase because there will be no lion to prey on them; as a result the deer population will increase which will graze on grasses. More the population of deer more will be the grazing on land. Overgrazing will lead to disappearance of vegetation and the forest will turn into a desert with no vegetation at all.
28. The number of malaria patients in a village increased tremendously when large numbers of frog were exported from the village. What could be the cause for it?
Answer
→ The cause for this is increase in number of mosquitoes in the village. When large numbers of frog were exported from the village, the population of mosquito would have increased. This is because frog is predator of mosquito i.e. they eat mosquitoes, but when there were no frogs left to eat mosquito; the mosquitos increased in number thus spreading malaria.
29. How does a biodegradable waste differ from a non-biodegradable waste? Give two examples of non �-biodegradable wastes which pollute our environment.
Answer
→ Biodegradable wastes are those that can be recycled or decomposed by bacteria; therefore do not need dumping sites, and also do not cause pollution. For example- paper, wood, vegetable peels etc. Whereas, non-biodegradable wastes are those that cannot be recycled or decomposed by bacteria (not degradable) and cause pollution in the environment. Non-biodegradable waste when dumped onto large area causes soil pollution due to the poisonous chemicals present in them. For example- plastic
For example- Plastic, DDT and polythene are three such examples of non-biodegradable waste that pollute the environment.
30. Which of the following are biodegradable and which non-biodegradable?
Glass bottle, Paper, Ball point pen refill, Hay, DDT, Wheat, Cake, Wood, Polythene bag, Jute bag, Cotton cloth, Grass, Vegetable peels.
Answer
BIO-DEGRADADABLE
|
NON- BIODEGRADABLE
|
1. Paper
|
1. Ball point pen refill
|
2. Wood
|
2. DDT
|
3. Vegetable peels
|
3. Polythene bag
|
4. Cake
|
4. Glass bottle
|
5. Wheat
| |
6. Hay
| |
7. Jute bag
| |
8. Cotton cloth
| |
9. Grass
|
31A. Describe an activity to show that while paper is biodegradable but plastic (say, polythene) is non- biodegradable.
Answer
→ (A) Activity- Dig a ground to 15cms depth and bury a paper and a polythene bag into it and cover it with earth. After a month or so, remove the soil from the buried area. You’ll find that the piece of paper had reduced in size because of being eaten up by the bacteria whereas the polythene bag remained as it is. The micro-organisms or the decomposers in the soil have decomposed paper. But, because the polythene bag remained as it was, it means that micro-organisms could not decompose/degrade the polythene bag.
This activity shows that paper is biodegradables and plastic is non-biodegradable.
31B. Explain why, some materials are biodegradable but some are non-biodegradable.
Answer
→ (B) From the above activity we can say that some materials are biodegradable because they can be decomposed by micro-organisms/decomposers. Some substances are non-biodegradable because the micro-organisms/decomposers cannot break or decompose them.
Decomposers are specific in their action.
32. Write down a food chain:
(a) In the sea
(b) Which ends with human-beings
(c) With five links in it.
Answer
→ a) Food chain in the sea-
b) Food chain that ends with humans.
c) Food chain with five links in it.
33. At which trophic level a person is feeding when he is eating:
(a) Roasted chicken
(b) Bread
(c) Eggs
(d) Apple
(e) Fish
Answer
→ a) Roasted chicken- Third trophic level/Secondary consumer. Chicken is primary consumer as it eats plant. Eating them will make a person a secondary consumer which is the third trophic level.
b) Bread- Second trophic level/Primary consumer. Bread is obtained from wheat plants. Eating products from plants will make a person primary consumer which is the second trophic level.
c) Eggs- Third trophic level/Secondary consumer. Egg comes from chicken which feeds on plants. Chicken are the primary consumer and eating a substance obtained from chicken will make the person a secondary consumer which is at the third trophic level, again.
d) Apple- Second trophic level/Primary consumer. Apple is obtained from plants. Eating products from plants will make a person primary consumer which is the second trophic level.
e) Fish-Fourth trophic level/Tertiary consumer. Fish is a carnivore which feeds on flesh of other animals. So fish is a secondary consumer. Eating fish will make a person tertiary consumer which is at the fourth trophic level.
34. A student went to study a local pond. In one part of the pond she noticed tadpoles scraping at some pond weed. In another part she saw a water beetle holding a tadpole in its jaws.
(a) Construct a food chain for the pond.
(b) How many links are there in this chain?
Answer
→ a) Food chain-
b) There are three links in this food chain. Tadpoles that are primary consumers eat pond weeds. Water beetles in turn eat tadpoles.
35. Construct.
(a) a long food chain, and
(b) a short food chain, ending with man.
Answer
→ a) A long food chain ending with man
b) Short Food chain ending with man
36A. State one advantage of using jute bags over plastic bags for shopping.
Answer
→ (A) one advantage of using jute bags over plastic bags is that jute bags are biodegradable and thus do not cause pollution. Whereas, plastic bags are non-biodegradable and they cause pollution by releasing toxic chemicals when burned.
36B. Write a common food chain of a pond ecosystem having four links.
Answer
→ (B) Pond ecosystem
Algae/producer are eaten by zooplankton like protozoan which are consumed by small fishes. Small fishes are prey of large fishes or large carnivores.
37. We do not clean ponds or lakes but an aquarium needs to be cleaned periodically. Why?
Answer
→ Ponds and lakes are complete ecosystems, they have decomposers which decompose the dead bodies of plants and animals and thus keep the ponds and lakes clean automatically.
Aquarium does not have decomposers to clean the dead remains of fishes, or the aquatic organisms; so they need to be cleaned periodically in order to remove the dead matter pile up.
38. What will be the consequence of the absence of decomposers in the ecosystem?
Answer
→ If decomposers get absent from the ecosystem then the dead remains of plants and animals will not be decomposed, as a result the dead matter would pile up and the nutrients will not be returned back to the plants through soil.
39. Give two differences between food chain and food web.
Answer
→ 1) A food chain is a single path of plants and animals eating each other and transferring energy accordingly. Food web is a network of interdependent food chains.
2) A food chain shows only one string of connected plants and animals and their food habits. On the other hand, a food web shows food habit of various plants and animals in an ecosystem.
40. Write one or two words for each of the following statements/definitions:
(a) Each level of food chain where transfer of energy takes place
(b) The physical factors like temperature, rainfall, light, soil, air and water of an ecosystem
(c) Organisms which depend on the producers for food either directly or indirectly
(d) The physical and biological world where we live in
(e) Self-contained unit of living things and their non-living environment needing only sunlight for its functioning
Answer
→ a) Trophic level;
10% energy transfer takes place from one trophic level to the other
b) Abiotic components of ecosystem;
Factors like temperature, rainfall, light, soil, air and water are abiotic components of the ecosystem.
c) Consumers;
Consumers feed on producers for food.
d) Environment;
The surroundings where living beings operate i.e. the physical and biological world of living beings.
e) Ecosystem.
A community wherein organisms interact with each other and their physical environment.