KPK Board 12th Class Biology Ch 25 Man and His Environment Short Questions Answers

Environment:  the surrounding in which the organism lives is called its environment; it consists of living components like plants, animals and microorganisms and nonliving components like air water soil temperature.

resources the things that man required for our survival and  comfort are called resources.

types renewable these resources can be produced when finished in soil water forest.

non-renewable resources cannot be reproduced when finished fossil fuels.

Conservation, maintaining the material resources of the environment and their careful use is called conservation.

it is a natural area the living organisms and their environment interact and exchange the materials between them ecosystem =  community+  abiotic environment

ecology the study of interrelationship of organisms and their environment is called Ecology it is also called environmental biology.

The part of earth where life exist Is called the biosphere.

The biosphere consists of the following parts: the atmosphere, this part consists of air.

lithosphere it is part of the Biosphere consisting of land Hydrosphere this part consists of water bodies.

Abiotic components these are the non living components environment abiotic components are following light water temperature atmosphere fire soil  inorganic material Gravity.

biotic components: the living components of an ecosystem are called biotic components plants animals microorganisms.

The specific locality with a  particular set of environmental conditions where an organism lives is called its habitat. Ecological niche ecological role of an organism in the ecosystem as well as its position in time and space is called niche.

The upper layer of the earth crust is called soil layers. The soil is composed of two layers of topsoil. It is the surface soil and is 20 to 30 cm thick.The roots of the plant are anchored in.

subsoil it lies below the topsoil and is light brown in colour it is largely composed of large Rock particles stones and water.

inorganic nutrients:   the nutrients are the substances used by organisms to get energy for the body activities. inorganic nutrients Include oxygen compounds of calcium nitrogen and phosphorus.

all these nutrients are important for the vital activities of the organisms.

Green plants are able to prepare food for themselves and for others animals for they are called the producers are autotrophs producers of Terrestrial ecosystem green rooted plants are the producer of Terrestrial ecosystem producers of Aquatic ecosystem phytoplanktons are the producers of Aquatic ecosystems.

organisms that cannot prepare their own food are called consumers.

Types:  primary consumers they directly feed on green plants.so also called herbivorous example cow goat Sheep.

Secondary consumers feed on Herbivorous and also called carnivorous frog lizard cat dogs.

tertiary consumers are the top consumers they feed on primary and secondary consumers, for example Line Tiger Hawk.

these organisms get their energy E from the remains of plants and animals they are also called saprophytes fungi and bacteria importance they are the cleaners of the environment they help in recycling of material like  nitrogen and carbon.

The process of eating and being eaten is called food chain links organisms are connected in food chains. Fore line are Arrow known as links example grasshopper – Rat – Snake – eagle.

Algae – zooplankton – Small fish –  largest fish – whale.

food web in ecosystem the interconnected food chains from a food web it is a graphical description of reading relationship among species in community. the lines in the Arrow in the food web are called the links. This link represents a  trophic for feeding levels.

The back and forth movement of chemical substances between environment and organism is known as biogeochemical cycle.

example carbon cycle.

process carbon circulates in the environment and organism in the following way.

plants use CO2 in photosynthesis to form glucose.

animals obtain carbon from plants by eating them.

herbivorous are eaten so the carbon is transferred to them.

carbon returns from the animals and plants to the environment for respiration decomposition and fertilization.

it is the most abundant element of the atmosphere. Important organisms need nitrogen to live and grow. nitrogen fixing is a process where nitrogen is converted into its compound. sources following are the source of nitrogen fixation. bacteria and nitrogen fixing bacteria rhizobium and algae convert nitrogen into its compound. high energy natural events some high energy natural events like lighting forest fire and Lava flow can also cause the fixation of small but significant amounts of Nitrogen.

it is the conversion of the ammonium into nitrates. sources of nitrification include nitrosomonas these bacteria convert the nitrogen into nitrites. nitrobacter. These bacteria convert the nitrites into nitrates. denitrification is the process through which nitrites and nitrates are converted back into molecular nitrogen. process the process of identification is brought about by a group of denitrifying bacteria called the pseudomonas .It is the only nitrogen transformation that removes the nitrogen from the ecosystem and roughly balances the amount of Nitrogen.

The Fast and the biggest threat to the environment is the sharp rise in population it controls is an urgent issue due to the following reasons to reduce burden and stabilize our resources to reduce famine. To reduce pollution to provide chances for the employment and better survival.

it is one of the most dangerous and widespread forms of pollution.

acid rain is mostly caused by the smoke and the gases given off by factories and vehicles and also by burning of fossil fuels. process during the process sulphur produced by fuse combines with their to produce SO2.

Some nitrogen in air produces nitrogen oxide. during rainfall both these oxide turn into sulphuric acid and nitric acid.Effects it can make the trees lose their leaves. soil become poisonous due to toxic deposition of acid rain. fishes and other organisms can die in severe acid rain. it can cause stone cancer.

when three atoms of oxygen combine together this triatomic molecule of oxygen is called the ozone layer. This layer is present around our earth that filters out ultraviolet rays of Sun that are harmful for life.Depletion of Ozone layer depletion is very dangerous for life because the race reaches the earth surface causing many health problems for plants and animals.

The addition of foreigin particles into the natural environment that can harm the living things is called pollution.Types important type of pollution are air, water and land pollution.

air pollution: it is the addition of harmful substances to the air. causes of air pollution include oxide of carbon, nitrogen and sulphur, chlorofluorocarbons, lead compounds.

water pollution :  water pollution occurs when pollutants are discharged directly or indirectly into water bodies. incomplete sewage, oil spills, Industrial waste, insecticides, chemical fertilizers.

land pollution;  it is the degradation of land surfaces often caused by human activities. of land pollution is increased urbanisation, increase in agricultural land, domestic waste.

air pollution produces  lungs functioning it causes irritation of eyes, nose, mouth and  throat. it increased respiratory diseases. It increases cardiovascular problems. air pollution can cause cancer.

Effects of water pollution water pollution causes many disease like typhoid, ascariasis, amoebiasis, respiratory infections, hepatitis, diarrhoea.

The following are some controlling measures of pollution recycling of materials used in organic cotton products. maximize for a station install sewage treatment plants use of wet scrubber in Chimney of power plants.

The use and reuse of the material in the living world is called recycling. In this process waste is renewed into a state from which new useful items can be produced. Advantage: it causes reduction in waste disposal. It helps in reductions of pollution. conservation of water. it saves energy and money . 

The repetition of water in the environment is called a water cycle.

Steps:

Evaporation is the type of vaporization that occurs from the surface of liquid. Condensation is the change of the physical  state of matters from the gas phase into liquid.

Precipitation is the product of condensation of atmospheric water vapours that falls on ground.

The cycling of Nitrogen atmosphere and organisms is called nitrogen cycle. nitrogen fixing and Ammonia fixation. nitrification and denitrification.

Nitrogen gas can be fixed in three  ways. atmospheric fixation:  it occurs spontaneously by lighting a small amount only fixed his way.

industrial fixation:  haber process is used to make the nitrogen fertilizer.Biological fixation nitrogen fixing bacteria fix 60% of Nitrogen gas in the atmosphere.

These are the graphical representations of productivity in the ecosystem. Pyramids of biomass is the representation of the amount of energy contained in Biomass at different trophic level.Higher level:  the higher  of trophic levels would have less total BiomassWhen does below because less energy is available to them. Pyramids of numbers are the representation of the number of organisms in each trophic level. Here each successive trophic level has fewer organisms the number of producers is largest.

nitrogen is the most important and abundant element of the atmosphere.

Importance of nitrogen is required by all organisms to live and grow. Plants nitrogen is important for plants to develop chlorophyll and make enzymes. animalsNitrogen is essential for animal life; it is a component of amino acids.

Interactions among living organisms are necessary for a balanced ecosystem. These interactions may be useful or harmful negative for  one or both of the interacting organisms.

Types:

Competition is the interaction between organisms for Limited supply of resources.

predation in this relationship one animal is  captured and killed and eaten by the other. Parasitism is a one sided relationship of two species in which one gets benefits and the other is harmed. Symbiosis  is a relationship between organisms of different species in which no one is harmed.

The sun rays reach the earth in the form of visible light and raise the earth temperature. radiation  this heat energy radiates back to space and the temperature of the earth remains in balance. CO2 layer due to pollution a thick layer of Co2 and other gases if formed prevents  re-radiation of heat energy  back to space. This warming of the earth’s surface is called the greenhouse effect.

Functions the thick layer of gases act like glass of green house. that allow the incoming solar ways but prevent the emission of the outgoing heat waves.

conservation means the protection  and preservation of natural resources; environmental conservation is the management of the Biosphere by man. types natural resources can be conserved in the following two ways directly and indirectly.

directly it can be directly conserved by taking care of natural resources. indirectly resources can be conserved indirectly by controlling human population and consequently reducing pollution.

When radioactive fuel assemblies are removed from nuclear reactors they are transported to swimming pools. storage facilities to dissipate the heat of decay of short lived isotopes as well. As for isolation from the environment the long-term disposal of these waste remains a major problem. It was assumed that the waste would be encased in glass and placed in geological disposal site in underground salt domes.

man is the main cause of resource depletion if activities are continuously consuming. the natural environment resources with the pace beyond renewal.Following are some factors for which managers depleting natural resources.

over consumption non equitable distribution over population slash and Burn agricultural practice technological and industrial development erosion irrigation Forestry meaning for oil and Minerals aquafire depletion pollution or contamination of resources.

A land where  saturation with water is the dominant factor determining the nature of soil is called a wetland. they act like giant sponge to filter water.

They provide Habitat to many species. They help in food control and short line stability; they also act as storage reservoirs.

clumped distribution attraction. uniform distribution repulsion. random distribution influence. Following are the types of population distribution.

These areDirectional non seasonal changes in the type of plant species that occupy a given area. types primary it is the establishment of plants on land not previously vegelated.

Secondary is the inversion of a habitat by plants on land that are  previously vegetated.

cutting trees at large scale is called deforestation, heavy soil erosion, extinction of flora and fauna.

relocation of wildlife to urban area. global warming. sitting of rivers and Dams. desertification. climatic changes. danger of Submersion of coastal areas and glaciers.