Biology class 10thClass Matric Part 2 Notes

10th class biology chapter 16 Man and His Environment

10th class biology chapter 16 Man and His Environment on by Bilal Article

Shorts and Simple Question & Answers

Q.1 What are the different levels of ecological organization?
The different levels of ecological organization are:
(i) species
(ii) population (iii) community (iv) ecosystem (v) biosphere

Q.2 Define ecosystem and its components.
The self-sufficient unit of an environment that is formed as a result of interactions between its communities and the abiotic components is called ecosystem.

Q.3 How flow of energy is different from that of materials?
The flow of energy in different trophic levels of ecosystem is unidirectional while the flow of materials is two directional. It flows from one trophic level to another by means of food chains and food web.

Q.4 Define food chain. Give one example (Board 2014)
A food chain is a series of organisms within an ecosystem, in which each organism feeds on the one before it and is fed by one after it.
Grass Grasshopper Sparrow → Hawk

Q.5 Define food web.
In nature, food chains are very complex, as an organism may be the food source of many other.
organisms. So there is a web like structure formed by these interlinked food chains. Such
interconnected food chains collectively make food web. OR It may also be defined as, “a network of food chains which are interconnected at various trophic levels”.

Q.6 What do you mean by the concept of 3Rs with reference to the conservation of natural
It means Reduce, Reuse and Recycle the materials. Many materials such as paper, plastic, glass etc can be recycled. This decreases the volume of refuse and helps in the conservation of natural

Q.7 Define Acid rains.
Certain chemicals such as oxides of sulphur and nitrogen when react with water vapours in the presence of sunlight to form sulphuric acid and nitric acid. These acids remain as vapours at high temperatures. As temperature falls, the acids begin to condense into liquid form and mix with rain or snow, on the way down to the earth. This makes rain acidic with pH range of 3-6.

Q.8 What is ammonification?
Ammonification is the breakdown of the proteins of dead organisms and nitrogenous wastes (urea, uric acid etc.) to ammonia. It is done by ammonifying bacteria.

Q.9 What is atmospheric nitrogen fixation?
Thunderstorms and lightning convert atmospheric gaseous nitrogen into nitrous acid and nitric acid. The acids in turn combine with other salts to produce ‘nitrates’ this is called atmospheric nitrogen fixation.

Q.10 What are biogeochemical cycles.
Biogeochemical cycles are the cyclic pathways through which materials move from environment to organisms and back to the environment. e.g. carbon cycle, nitrogen cycle etc.

Q.11 What is biological nitrogen fixation?
Some bacteria also have the ability to transform gaseous nitrogen into nitrates. It is called biological nitrogen fixation. Some of these nitrogen fixing bacteria live as symbionts and many are free living.

Q.12 Define Biosphere.
All ecosystems of the world together form the biosphere. It includes all the ecosystems of the earth. In other words, the biosphere consists of all organisms present on the earth and all regions of the earth where they live. Biosphere ranges from the floor of oceans to the top of the highest mountains. It is about 20 km thick.

Q.13 What is carbon cycle?
The biogeochemical cycle in which carbon flows between organisms and the environment is called carbon cycle.

Q.14 What are carnivores? Write the types of carnivores.
Those animals that feed upon other animals are called carnivores.
Types of carnivores
a) Primary carnivores
Those carnivores that feed upon herbivores are called primary carnivores.
Fox, frog, predatory birds, many fishes and snakes.
b) Secondary carnivores
Those carnivores that feed upon primary carnivores are called secondary carnivores.
Wolf and owl etc.
c) Tertiary carnivores
Those carnivores that feed upon secondary carnivores are called tertiary carnivores. They are not eaten by any other animals. So they are also called top carnivores.
Lion, Tiger etc.

Q.15 Define commensalism with examples.
It is a type of symbiosis in which one partner is benefited while the other is neither benefited nor harmed.
Epiphytes are small plants found growing on other larger plants for space only. They absorb water and minerals from the atmosphere and prepare their own food. The larger plants are neither benefited nor harmed in any way.

Q.16 What are consumers?
These are the heterotrophs in an ecosystem. These organisms are unable to synthesize their food and so depend upon producers for food. The animals are the major consumers of all the ecosystems.
Animals, Fungi, Protozoans and many of the Bacteria.

Q.17 What are decomposers?
Those organisms that break down the complex organic compounds of dead matter (of plants and animals) into simple compounds. They secrete digestive enzymes into dead and decaying organic matter to digest the organic material. Products of digestion are absorbed for their own use and remaining substances are added to the environment for reuse.
Bacteria and fungi

Q.18 Define Deforestation and describe its causes.
Deforestation means clearing of forests by natural causes or humans. Causes of deforestation m
Large areas of forests have been cleaned for agriculture, factories, roads, rail tracks and mining.
Humans cut trees for getting wood (Timber), which is then used for making structures and for
heat production.
Human preys upon forest animals, which are the predators of many insect pests. In this way insect pests destroy forests by eating the shoots and spreading diseases.
Effects of deforestation
Soil erosions
Global warming
Loss of habitat of many species

Q.19 What is meant by denitrification?
It is a biological process in which nitrites and nitrates are reduced to gaseous nitrogen by denitrifying bacteria. In this way, nitrogen is returned to the atmosphere.

Q.20 What is ecological pyramid?
Ecological pyramid can be defined as, “A representation of the number of individuals or amount of biomass or energy present in various trophic levels of a food chain”.

Q.21 Define environment.
An organism’s environment is the sum of physical (abiotic) and biological (biotic) conditions which influence that organism.

Q.22 What is eutrophication?
Enrichment of water with inorganic nutrients (nitrates and phosphates) is called eutrophication.

Q.23 What is Global Warming and describe its effects.
The addition of greenhouse gases (e.g. carbon dioxide, methane, ozone) in atmosphere increases the temperature of the earth. Gases in the atmosphere do not allow solar radiations to reflect back into space. As a result, heat remains within the earth’s atmosphere and increases its temperature. This is called global warming.
Effect of global warming
Due to global warming, polar ice-caps and glaciers are melting faster than the time taken for new ice layers to form. Sea water is also expanding causes sea level to rise due to melting glaciers, rivers overflow and cause floods.

Q.24 Define mutualism.
The type of symbiosis in which both partner get benefit from each other and neither is harmed. Example
Termites eat wood but are unable to digest it. A protozoan lives in its intestine. It secretes. ‘cellulase’ enzyme to digest the cellulose of wood. In turn, the termite provides food and shelter to the protozoan.

Q.25 What are natural resources?
Every thing we use e.g. food, petrol etc. is obtained from natural resources. They are of two
types. (i) Renewable
(ii) Non-renewable

Q.26 What is nitrification?
After the formation of ammonia, it is converted into nitrites and nitrates. This is called nitrification and is done by nitrifying bacteria.

Q.27 What is nitrogen cycle?
The flow of nitrogen between environment and the organisms is called nitrogen cycle.

Q.28 What is nitrogen fixation?
Conversion of nitrogen gas into nitrates is called nitrogen fixation.

Q.29 What are non-renewable resources and renewable resources?
The renewable natural resources e.g. air are reproduced easily but the non-renewable resources (e.g. minerals and fossils fuels) are not replenished once they get depleted.

Q.30 What is overpopulation?
Increase in population beyond the carrying capacity of an area

Q.31 Define phytoplankton?
Photosynthetic organisms that float on the surface of water, are called phytoplankton.

Q.32 Define Pollution and pollutants.
Pollution is defined as any undesirable change in the physical, chemical or biological characteristics of air, water and land that may harmful for humans, other living organisms and natural resources. The substances that actually cause pollution are called pollutants.

Q.33 Define parasitism.
It is a type of symbiosis in which smaller partner (parasite) derives food and shelter from the body of larger partner (host) and, in turn, harms it.

Q.34 What is predation?
An interaction between animals of two species or a plant and an animal, in which the predator attacks, kills and feeds on the smaller animal called prey.

Q.35 What are producers?
These are the autotrophs in an ecosystem. These organisms are able to synthesize complex organic compounds (food) from inorganic raw materials. Producers form the basis of any ecosystem.
Examples Plants, Algae and Cyanobacteria

Q.36 Define pyramid of biomass.
It is a graphic representation of biomass present per unit area at various trophic levels of a food chain.
In a terrestrial ecosystem, the maximum biomass is of producers and decomposers have lesser biomass.

Q.37 Define pyramid of numbers.
It is a graphic representation of the number of individuals per unit area at various trophic levels of a food chain.
Example Usually, producers are present in large number, primary consumers are in lesser number, and secondary consumers are fewer.

Q.38 Define symbiosis.
It is a relationship between members of different species, in which they live together for longer or shorter period of time.
Lichens (Association between algae and fungi)

Q.39 Define Ecology.
The study of the interrelationship between living organisms and their environment is called ecology.

Q.40 Define Species.
A species is a group of organisms which can interbreed freely in nature to produce fertile offspring.
Example Human, Cat, Dog etc.

Q.41 Define Ecosystem.
The self-sufficient unit of an environment that is formed as a result of interactions between its biotic communities and the abiotic components is called ecosystem.

Q.42 What are herbivores?
These animals feed directly on plants or products of plants. They are also called primary consumers.
Cattle, deer, rabbit, grasshopper etc.

Q.43 What are omnivores?
Those consumers that eat animal flesh as well as plants and plant products are called omnivores.
Human, Crow

Q.44 Define trophic level.
Trophic level is the level at which an organism feeds in food chain. The first trophic level is made of producers; the second of primary consumers and so on.

Q.45 Define pyramid of energy.
It is a graphic representation of energy present in a biomass of living organisms at various trophic levels of a food chain.
The amount of energy is decreased from producers to decomposers as some amount of energy is used by the organisms to perform work while some of it is lost as heat.

Q.46 What is meant by assimilation?
It is a process in which the nitrates are absorbed by plants and are utilized for making proteins, nucleic acid etc. Animals take nitrogenous compounds from plants. The utilization of nitrates by organisms is called assimilation.

Q.47 What is parasite?
A parasite is an organism that gets shelter and food from its host and in return harms it.
Examples Plasmodium, Amoeba etc.

Q.48 Define Urbanization.
Urbanization means growing of cities. People move from rural areas to cities in search of better jobs, education opportunities and higher standards of living.

Q.49 What are primary consumers? Give one example.
The organisms which feed directly on plants or products of plants are called primary consumers.
e.g. sheep, goat etc.

Q.50 Write four effects of air pollution.
i. Smog formation
ii. Acid rains
iii. Ozone depletion
iv. Global warming

Q.51 Define pollutants.
The substance that actually cause pollution called pollutants. They may be industrial effluents, domestic wastes, medical wastes etc. Pollutants are of two types:-
a. Biodegradable and
b. Non-biodegradable

Q.52 What is noise? Write its Effects.
Unwanted and annoying sounds are termed as noise. Effects of noise pollution are aggression, hearing loss, depression, hypertension etc.

Q.53 What is green house effect?
Certain gases trap heat in environment. These gases act like the glass in a green house which does not allow the inner heat to escape. When sunlight reaches to earth surface, much of its energy is converted into heat energy. Earth reflects the heat energy back into space in the form of infra-red radiation. Green house gases (CO2, CH4, Nitrous oxide) trap these infra-red radiations and send it back to earth.

Q.54 What is global warming?
The addition of green house gases (e.g; carbon dioxide, methane, ozone) in atmosphere increases the temperature of the earth. These gases remain in the lowest part of earth’s atmosphere and do not allow solar radiations to reflect back into the space. As a result, heat remains within the Earth’s atmosphere and increases its temperature. This is called global warming.

Q.55 Define biomass?
The total amount of living or organic matter in an ecosystem at any time is called biomass.

Q.56 Define nutrient cycle?
The movement of elements and inorganic compounds from environment to organisms and back to environment.

Q.57 What are the effects of denitrification?
Excessive denitrification reduces soil fertility and is stimulated by water-logging, lack of aeration and accumulation of organic matter in the soil.

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1.Which of the following is the abiotic component of an ecosystem?
(a) Producers
(b) Herbivores
(c) Carnivores
(d) Oxygen✅

2.When we eat the onion, our trophic level is;
(a) Primary consumer✅
(b) Secondary Consumer
(c) Decomposer
(d) Producer

3.Identify the correctly matched pair:
(a) Rainfall- biotic factors in ecosystem
(b) Global warming- formation of fossil fuels
(c) Renewable natural resources-air✅
(d) Corn- secondary consumer

4.In the food chain tree — caterpillar robin hawk coyote, which is secondary consumer?
(a) Caterpillar
(b) Robin✅
(c) Hawk
(d) Coyote

5.In an ecosystem the flow of is one way, while is/are constantly recycled.
(a) Minerals, energy
(b) Energy, minerals✅
(c) Oxygen, energy
(d) Glucose, water

6.In the food chain “grass rabbit fox — bear mushroom”, how many types of decomposers are present?
(a) 1✅
(c) 3
(b) 2
(d) 4

7.Organisms in the ecosystem that are responsible for the recycling of plant and animal wastes are;
(a) Consumers
(b) Producers
(c) Decomposers✅
(d) Competitors

8.Which form of Nitrogen is taken by the producers of the ecosystem?
(a) Nitrogen gas.
(b) Ammonia
(c) Nitrites
(d) Nitrates✅

9.The type of environment in which a particular species lives is called;
(a) Ecosystem
(b) Habitat✅
(c) Biosphere
(d) Community

10.Which of the following organisms are decomposers?
(a) Fungi
(c) Bacteria
(b) Algae
(d) Both a & c.✅

11.The lowest trophic level of an ecosystem always includes:
(a) Herbivores
(b) Carnivores
(c) Producers✅
(d) Decomposers

12.Habitat destruction can result in a loss of:
(a) Species✅
(b) Population
(c) Community
(d) Ecosystem

13.The type of symbiotic relationship in which one member get benefit and other is unaffected is called:
(a) Parasitism
(b) Mutualism
(c) Commensalism✅
(d) Predation

14.Which one is not an example of abiotic factor?
(a) Decomposers✅
(b) Light
(c) Water
(d) Soil

15.An organism that actively hunts other organisms is called:
(a) Prey
(b) Predator✅
(c) Parasite
(d) Host

16.The type of symbiotic relationship in which one member get benefit and other is harmed is called:
(a) Parasitism✅
(b) Mutualism
(c) Commensalism
(d) Predation

17.Organisms that make their own food with help of sunlight, CO₂ and H₂O are called;
(a) Consumers
(b) Producers✅
(c) Decomposers
(d) Predators

18.The conversion of ammonia to nitrates is carried out by soil bacteria. This process is called:
(a) Nitrification✅
(b) Denitrification
(c) Nitrogen fixation
(d) Assimilation

19.A group of organisms, similar to one another, which can interbreed in nature and produce fertile offspring:
(a) Species✅
(b) Genus
(c) Family
(d) Population

20.Water, soil, air, temperature, wind and sunlight are examples of:
(a) Biotic factors
(b) Biomass
(c) Environment
(d) Abiotic factors✅

21.A relationship between two organisms in which individual of one species may kill and eat individuals of other species is called:
(a) Symbiosis
(b) Competition
(c) Predation✅
(d) Mutualism

22.A relationship between species in which both species benefit is called:
(a) Parasitism
(b) Mutualism✅
(c) Symbiosis
(d) Commensalism

23.The self-sufficient unit of environment that is formed as a result of interaction between its biotic community and its abiotic components is known as:
(a) Biosphere
(b) Habitat
(c) Ecosystem✅
(d) Food web

24.A network of all the feeding relationships in an ecosystem is called:
(a) Food chain
(b) Food web✅
(c) Trophic level
(d) Energy flow

25.The thickness of biosphere is:
(a) 02 km
(c) 50 km
(b) 20 km✅
(d) 200 km

26.get solar energy and transform it into chemical energy by the process of photosynthesis.
(a) Decomposers
(b) Producers✅
(c) Consumers
(d) Predators

27.The materials flow from one trophic level to the next by means of;
(a) Food chains
(b) Food web
(c) Both a & b✅
(d) None

28.The base of food chain is always formed by;.
(a) Producers✅
(b) Consumers
(c) Decomposers
(d) Heterotrophs

29.In 1927, developed the concept of ecological pyramids.
(a) Kelvin
(b) Lamarck
(c) Charles Elton✅
(d) Charles Darwin

30.atom is the principal building block of many kinds of biomolecules.
(a) Oxygen
(b) Carbon✅
(c) Hydrogen
(d) Nitrogen

31.Which one of the following is not an example of fossil fuels?
(a) Plants✅
(b) Peat
(c) Coal
(d) Natural Gas

32.The major process that brings carbon from atmosphere into living world is:
(a) Photosynthesis✅
(b) Respiration
(c) Both a & b
(d) None

33.Nitrogen is an important component of:
(a) Proteins
(b) Nucleic Acid
(c) Lipids
(d) Both a & b✅ the breakdown of the proteins of dead organisms to ammonia.
(a) Ammonification✅
(b) Nitrification
(c) Denitrification
(d) None

35.The utilization of nitrates by organisms is called:
(a) Nitrification
(b) Ammonification
(c) Assimilation✅
(d) Denitrification

36.Which one of the following is not a temporary parasite?
(a) Mosquito
(b) Virus✅
(c) Leech
(d) Bed bug

37.Which one of the following is not an endoparasite?
(a) Ascaris
(b) Plasmodium
(c) Entamoeba
(d) Mosquito✅

38.An epiphyte is an example of:
(a) Parasitism
(b) Mutualism
(c) Commensalism✅
(d) Symbiosis

39.Which one is an example of epiphyte?
(a) Mosquito
(b) Orchid✅
(c) Rhizobium
(d) Plasmodium

40.Which of the following is not an example of green house gas?
(a) CO2
(b) Methane
(c) Oxygen✅
(d) Nitrous Oxide

41.The current level of urbanization in Pakistan is about which is not high by global standards.
(a) 23%
(b) 32%✅
(c) 36%
(d) 39%

42.Abiotic component of ecosystem is;
(a) Producers
(b) Herbivores
(c) Carnivores
(d) Oxygen✅

43.A symbiotic interaction in which both partners get benefits;
(a) Mutualism✅
(b) Commensalism
(c) Parasitism
(d) Predation

44.The consumers that eat animal flesh as well as plants and plant products are called: (Board 2013)
(a) Herbivores
(b) Carnivores
(c) Omnivores✅
(d) Insectivores

45.Living of nitrogen fixer bacteria in the root nodules of leguminous plants is an example of;
(a) Predation
(b) Parasitism
(c) Mutualism✅
(d) Commensalism

46.The perfect cycle is;
(a) Carbon cycle✅
(b) Nitrogen cycle
(c) Water cycle
(d) All of the above

47.Nitrogenous waste includes;
(a) Ammonia
(b) Urea✅
(c) Uric acid
(d) All of the above

48.Plants show competition for;
(a) Space
(b) Light
(c) Water and Minerals
(d) All of the above✅

49.Flow of energy is always;
(a) Unidirectional✅
(b) Two directional
(c) Multidirectional
(d) No directional

50.IPCC stands for;
(a) International project of climate change
(b) Intergovernmental Project of climate change
(c) Intergovernmental panel on climate change✅
(d) International panel on climate change

51.The temperature of Earth’s surface has increased per decade in the past 30 years;
(a) 0.1°C
(b) 0.2°C✅
(c) 0.3°C
(d) 0.4°C

52.Since 1800, amount of CO2 in atmosphere has increased about;
(a) 20%
(b) 30%
(c) 40%
(d) 50%

53.Since 1800, amount of nitrous oxide has increased about;
(a) 2%
(b) 6%
(c) 8%✅
(d) 10%

54.According to estimate at the current rate of increase, the average global temperature will go upto by in the next 100 years.
(a) 8°C
(b) 6-8°C
(c) 3-8°C✅
(d) 5-8°C

55.Pakistan growth rate in 1991 was;
(a) 2%
(b) 2.50%
(c) 2.69%✅
(d) 2.89%

56.In 2003, a survey on tanneries in Kasur City showed that of cancer residents suffered from infections of kidney or loss of eyesight.

57.Recycling of one tonne paper can save.
(a) 10 trees
(b) 15 trees
(c) 18 trees
(d) 17 trees✅

58.people are at risk of dengue.
(a) 1.5 billion
(b) 2.5billion✅
(c) 3.5 billion
(d) 2.5 million

59.Scientists fear that sea level is rising upto per year.
(a) 0.8 cm
(b) 10 cm
(c) 0.9 cm✅
(d) 9 cm

60.It is estimated that Maldives might become uninhabitable within;
(a) 50 years
(b) 80 years
(c) 100 years✅
(d) 130 years

61.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) Stable community
(c) Ecosystem✅
(d) Ecological succession

62.The living organisms which cannot prepare their own food but obtain ready made food from others, are;
(a) Primary and Secondary consumers
(b) Secondary and tertiary consumers
(c) Only primary consumers
(d) All types of Consumers.✅

63.How many tanneries are operating in Kasur city;
(a) More than 300
(b) More than 200✅
(c) 500
(d) 1000

64.Upper layer of the atmosphere is called;
(a) Biosphere
(b) Lithosphere
(c) Hydrosphere
(d) Stratosphere✅

65.At which trophic level in a food chain, carnivores get food?
(a) First trophic level
(b) Second trophic level
(c) Fourth trophic level
(d) Third trophic level✅

66.Fungi digest the dead organic matter with the help of;
(a) Enzymes✅
(b) Acids
(c) Hormones
(d) Bases

67.Which is an ectoparasite?
(a) Liver fluke
(b) Ascaris
(c) Tape worm
(d) Leech✅

68.The favourable variations tend to be;
(a) Eliminated
(b) Passed to next generation✅
(c) Unexpressed
(d) Changed

69.Habitat is an example of;
(a) Biological character
(b) Chemical character
(c) Physical Character✅
(d) Behavioural character

70.A group of organisms which can interbreed freely in nature to produce fertile offspring is called;
(a) Population
(b) Community
(c) Species✅
(d) Ecosystem

71.An Aquarium is an example of Ecosystem;
(a) Natural
(b) Artificial✅
(c) Aquatic
(d) Terrestrial

72.Graphic representation of the number of individuals per unit area at various trophic levels of a food chain is called;
(a) Pyramid of Biomass
(b) Pyramid of numbers✅
(c) Pyramid of energy
(d) Food web

73.More than normal denitrification change the richness of soil as;16(085)
(a) Increase
(b) Less✅
(c) Bad
(d) Finished

74.An example of Carnivore plants is:
(a) Rose plant
(b) Mosses
(c) Pitcher plant✅
(d) Ferns

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