வேதநதி

ECOSYSTEM

A 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 B 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Section-A

1.Fungi in a forest ecosystem is

Producer
Decomposer
Top consumer
Autotroph
Ecosystem is composed of biotic components and abiotic (non-living) components. The biotic components of forest ecosystem are primary consumers (e.g., rabbit, moles, deer, squirrels, grasshoppers, etc), secondary consumers (e.g., carnivorous, birds, snake, lizard, etc) and decomposers (fungi and bacteria). In tropical and subtropical forests, rate of decomposition is more rapid than temperate.

2.In which layer of soil decomposition occurs at maximum rate?

Upper layer of soil
Middle layer of soil
Lower layer of soil
None of these
Upper layer of soil.
Decomposition is the process of breaking down a substance into its constituent parts. Decomposition of dead organic matter (plants, animals and waste products of animals) occurs in nature and it is also called decay or putrification. In a terrestrial ecosystem, the upper layer of soil is the main site of decomposition

3.The pyramid of number of a parasitic food chain in tree ecosystem is

Always inverted
Always upright
Mixture of inverted and upright
Sometimes inverted and sometimes upright
The pyramid of numbers deal with the number of primary producers and consumers. It is upright in a grassland and inverted in a tree ecosystem. In a grassland the number of producers is more than the number of top carnivores, whereas in case of a tree, the number of producers is less as compared to consumers

4.Secondary productivity is

The rate of formation of new organic matter by consumers
Greater than primary productivity
5% less than primary productivity
Equal to the gross primary productivity
The rate of formation of new organic matter by consumers is called secondary productivity

5.Food chain consists of

Plants
Herbivores
Carnivores
All of these
The food chain consist of producers, consumers and decomposers. Consumers are often of 3-5 types
First order (Primary) – Herbivores
Second order (Secondary) – Primary carnivores
Third order (Tertiary) – Secondary carnivores
Fourth order (Quaternary) – Top carnivores

6.Broad-leaved forests of oak are found in

Tropical deciduous forest
Tropical evergreen forest
Temperate deciduous forest
North coniferous forest

7.Group of two or more than two plant species is called as

Plant community
Animal ecosystem
Plant ecosystem
Ecological niche
A population consists of organisms of a particular species and has characteristics like natality, mortality, age structure growth dynamics, etc. When several populations share a common habitat and its resources, they interact among themselves and develop into a biotic community. Hence, community is a larger unit than a population.

8.Consider the following statements concerning food chains.
I. Removal of 80% tigers from an area resulted in greatly increased growth of vegetation.
II. Removal of most of the carnivores resulted in an increased population of deers.
III. The length of food chains is generally limited to 3 to 4 trophic levels due to energy loss.
IV. The length of food chains may vary from 2 to 8 trophic levels.
Which two of the above statements are correct?

II and III
III and IV
I and IV
I and II
The series of organisms eating one and being eaten by other is called food chain. A simple food chain consists of producers, herbivores and carnivores. The length of food chain is generally limited to 3-4 trophic levels due to energy loss. In grazing food chain, the producers (i.e., plants) are eaten by herbivores (i.e., rabbit, dear, cow, etc) and are eaten by carnivores. Therefore, the removal of most of the carnivores resulted in an increased population of deers.

9.Ecosystem may be defined as

A species along with environment
Plants found in water
Plants found on land
All plants and animal species along with their environment
An ecosystem may be defined as a structural and functional unit of the biosphere, comprising living organisms and their non-living environment that interact by means of food chains and chemical cycles resulting in energy flow, biotic diversity and material cycling to form a stable, self-supporting system

10.The green plants in an ecosystem which can trap solar energy to convert it into chemical bond energy are called

Producer
Decomposer
Consumer
Predators
Producers are autotrophs organisms, which alone are able to manufacture organic food from inorganic raw materials in the process of photosynthesis. The energy for this process is obtained from solar radiations or sunlight

11.In an ecosystem, the insectivorous plants are placed in

Herbivores
Primary producers
Predators
None of these
Insectivorous plants are autotrophs as they have chlorophyll. They don’t eat insects for food, but use them as a source of N and P and use light to transform them into biomolecules

12.In primary succession in water, the pioneer species are

Free floating angiosperm
Small phytoplanktons
Rooted hydrophytes
Lichens
In primary succession in water the pioneer species are small phytoplanktons, e.g., diatoms, green flagellates, single-celled colonial or filamentous green algae

13.Which of the following pyramid is always upright and can never be inverted?

Pyramid of biomass
Pyramid of number
Pyramid of energy
Both Pyramid of biomass and energy
Pyramid of energy represents amount of energy traped per unit area and time in different trophic levels of a food chain. It is always upright.

14.The products of decomposition process are

Humus
Inorganic nutrients
Organic nutrients
Both Humus and Organic nutrients
The end result of decomposition is the production of dark brown, smelling, humus rich organic matter and inorganic substance like carbon dioxide, water and nutrients

15.Vegetable eating person acts as

primary producer
primary consumer
secondary consumer
tertiary consumer
Primary consumers in an ecosystems are herbivores, which feed directly on producer (green plants)

16.In ecological pyramid the base always represent the _A_ and the apex represents _B_ Here A and B represents

A-producers; B-top level consumers
A-top level consumer; B-producers
A-producers; B-secondary consumers
A-producers; B-primary consumers
A-Produces; B-Top level consumers

17.A pyramid of number in grassland ecosystem shows

There are always a large number of producers at the bottom and fewer top consumers
There are always a large number of top consumers and fewer producers
There are an equal number of producers and consumers
There are more top consumer than primary consumers
In a grassland ecosystem, the number of producers is more than the number of top carnivores, whereas in case of a tree, the number of producers is less as compared to consumers

18.To show how many organisms are present at each level of a food chain, ecologists use a model called

An energy flow pyramid
Pyramid of numbers
Pyramid of energy
Food chain/food web pyramid
Pyramid of number is used to know how many organisms are present at each level of a food chain

19.The organisms which physically and chemically breaks the complex dead organic remains are known as

Scavangers
Decomposers
Both Scavangers and Decomposers
Parasites
Decomposers (saprotrophs) are the organisms that breakdown complex organic matter into inorganic substances and in doing, so they carryout the natural process of decomposition

20.Which one of the following is not a functional unit of an ecosystem?

Productivity
Startification
Energy flow
Decomposition
Vertical distribution of different species occupying different levels is called stratification. For example, in forest ecosystem, trees occupies the top vertical strata, shrubs occupies the second and herbs, grasses occupies the bottom layer. It is not a functional unit of an ecosystem

21.The food chain which begin with dead organic matter is called

Detritus food chain
Predator food chain
Parasitic food chain
Ecosystem
Detritus Food Chain (DFC) begins with detritus or dead organic matter. Detrivores and decomposers feed over it

22.In what order do a hawk, grass and rabbit form a food chain in a meadow?

Hawk → grass → rabbit
Grass → hawk → rabbit
Rabbit → grass → hawk
Grass → rabbit → hawk
Producers(Grass) → Herbivores(Rabbit) → Carnivores(Hawk)

23.Lichens that start the succession on a rock belongs to

Climax community
Intermediate community
Pioneer community
Seral community
Pioneer community.
Primary succession on rocks starts with lichen of species Rhizocarpon, Rinodina and Lecanora. They produce some acids which bring about weathering of rocks. These lichens are then replaced by foliose type of lichens. Due to description and retention of water by them, they from a fine thin soil layer on rock surface and thus there, is a change in the habitat

24.Which of the following ecosystem types has the highest annual net primary productivity?

Tropical rain forest
Tropical deciduous forest
Temperate evergreen forest
Temperate deciduous forest
Productivity of tropical rainforest is highest. The tropical rain forest covering 300,000 $Km^2$ area. They contain more than 50% of total flora and fauna of the world.

25.The factors influencing the rate of decomposition are

Temperature
Moisture
Both Temperature and Moisture
Catabolism
Climatic conditions like temperature, moisture and chemical composition affects the rate of decomposition

26.Which of the following factor is contributing to an overload of the carbon cycle?

Photosynthesis
Cellular respiration
Deforestation
Aforestation
Human activities like deforestation and vehicular burning of fossil has caused an increase in the amount of $CO_2$ in atmosphere

27.Consider the following statements about pyramid of biomass
I. When we plot the biomass (net dry weight) of producers, herbivores, carnivores and so on we have a pyramid of biomass
II. Two types of pyramid of biomass are found, i.e., upright and inverted
III. When larger weight of producers support a smaller of biomass weight of consumers an upright pyramid results
IV. When smaller weight of producers support larger weight of consumers an inverted pyramid of biomass is formed
Which of the statements given above are correct?

I, II and III
I, III and IV
II, III and IV
I, II, III and IV
The amount of living matter present in an ecosystem is known as biomass. It is upright in case of a tree, which supports a large number of birds and inverted in a pond, where a large fish eats upon a large number of phytoplanktons

28.Which one of the following is one of the characteristics of a biological community?

Stratification
Natality
Mortality
Sex ratio

29.Which one of the following correctly represents as organism and its ecological niche?

Vallisneria and pond
Desert locust (Scistocerca) and desert
Plant lice (aphids) and leaf
Vultures and denes forest
The term ‘niche’ was for the first time used by Grinnel (1971) to explain micro-habitats. According to him ‘niche’ is the ultimate distributional unit, within which each species is held by its structural and instinctive limitation. Actually niche is the complete account of how an organism uses its environment. Thus, plant lice (aphids) and leaf is the pair correctly representing the organism and its ecological niche.

30.Another name of nutrient cycling is

Gaseous cycle
Sedimentary cycle
Biogeochemical cycle
Carbon cycle
Another name of nutrient cycle is biogeochemical cycle. The movement of nutrient elements through various components (abiotic and biotic) of an ecosystem is called nutrient cycling or biogeochemical cycle

31.Identify the correct type of food chain.
Dead animal → Blow fly maggots → Common frog → Snake

Grazing food chain
Detrital food chain
Decomposer food chain
Predator food chain
Organic remains (dead plant parts, animal remains and excretions) are also called detritus. A food chain, which begins with detritus or dead organic matter is called detritus food chain. The energy passes into decomposers and detrivores, then to smaller carnivores, then to larger carnivores and so on.

32.Greater primary productivity depends upon

Rain (humidity)
Availability of nutrients
Both Rain (humidity) and Availability of nutrients
None of these
Rain (humidity) is required for higher primary productivity. Desert have the lower primary productivity as the soil is deficient in moisture. Greater nutrients ensure greater primary productivity

33.Building of biomass or storage of energy by green plants in a unit time and area is called

Productivity
Net primary productivity
Gross primary productivity
Primary productivity
Net primary productivity is the weight of the organic matter stored by the producers in a unit area/volume for unit time. It is given by NPP = GPP – R (Gross Primary Productivity) where, R = Respiration losses. It is utilised by hetertrophs

34.Stratification is more pronounced in

Tropical rainforest
Deciduous forest
Temperate forest
Tropical savannah
Stratification is more common in tropical rainforest. Stratification occurs vertically and determined by height of organisms
For example, in a forest community, stratification takes place when trees of different species grow to different heights

35.What is true about the phosphorus cycle?
I. Rocks are the natural reservoirs of phosphorus
II. Weathering of sedimentary rocks makes phosphate available to the soil
III. Herbivores and carnivores obtain phosphorus from plant directly or indirectly
Choose the correct option

I and II
I and III
II and III
I, II and III
The major reservoir for phosphorus is in phosphate rocks and fossil bone deposits laid down in the past geological ages. There is no atmospheric phase in the phosphorus cycle
Phosphorus becomes available in the soil for plants use by natural erosion of rocks and by human efforts
Plants takes up phosphorus form the soil. Animals get it from the plants directly or through other smaller animals. Animals excrete phosphorus mainly as phosphates, which the plants can use immediately

Section-B

36.Primary succession on rocks starts with

Lichen
Grass
Mosses
Ferns
Primary succession on rock starts with lichen of species Rhizocarpon, Rinodina and Lecanora. They produce some acid, which bring about weathering of rocks. That result into soil formation

37._A_ is required for higher primary productivity._B_ have the lowest primary productivity as the soil is deficient in moisture.
Choose the correct option for A and B

A-Rain; B-desert
A-Heat; B-forest
A-Rain; B-forest
A-Forest; B-desert
Rain is required for higher primary productivity. Desert have the lowest primary productivity as the soil is deficient in moisture

38.In plant succession, when climax community is reached, the net productivity

Continues to increase
Becomes zero
Becomes reduced
Becomes stable

39.The amount of living matter present in an ecosystem at a given time is called

Biomass
Standing crop
Standing state
Productivity

40.Which of the following is the logical sequence of primary succession in rocks?

Small bryophytes → Lichen → Herb → Shrubs → Tress → Forest
Lichen → Small bryophytes → Herbs → Shrubs → Tress → Forest
Lichen → Herb → Shrubs → small bryophytes → Tress → Forest
Herb → Shrubs → Lichen → Small bryophytes → Tress → Forest
Lichen → Small bryophytes → Herb → Shrubs → Tress → Forest

41.What is the medium by which carbon cycle takes place?

Through atmosphere
Through ocean
Through living and dead organisms
All of the above
The carbon cycle occurs through atmosphere ocean and through living and dead organisms. It is estimated that $ 4×10^{13}$ Kg of carbon is fixed in the biosphere through photosynthesis annually

42.Niche is defined as the

Position of species in a community in relation to other species
Place where organism lives
Place where organism lives and performs its duty
Place where population perform their duties

43.Percentage of Photosynthetically Active Radiation (PAR) that is captured by plants in synthesis of organic matter is

50-80%
40-60%
70-100%
2-10%
2-10%.
Out of the total incident solar radiation, only 50% of it is Photosynthetically Active Radiation (PAR). Plants capture only 2-10% of the PAR and this small amount of energy sustains the entire living world

44.Select the matched ones.
I. Sedimentary nutrient - Nitrogen cycle
II. Pioneer species - Lichens
III. Secondary succession - Burned forests
IV. Pyramid of biomass in sea - Upright

I, II and IV only
I and III only
II and III only
II and IV only
The successive development of different biotic communities at the same site till a climax community develops there, is called ecological succession (Hutt; 1885). The species that invade a bare area are celled pioneer species. In primary succession on rocks (xerarch succession) these are usually lichens which are able to secrete acids (lichenic acid) to dissolve rock, helping in weathering and soil formation. These later pave way to some very small plants like bryophytes (e.g., Mosses) which are able to take hold in the small amount of soil.
Secondary succession or subsere is a biotic succession on a secondarily bare area, e.g., burned forests, area after deforestation. It takes 50-100 years (for grassland) and 100-200 years(for forest). Ferns are generally the first to grow after the forest fire because of their underground rhizomes.

45.The sunlight directly regulates the primary productivity because

Gross primary productivity is utilised by plants in respiration
The plants perform respiration with the help of sunlight
The plants perform photosynthesis with the help of sunlight
None of the above
The sunlight directly regulates the primary productivity because the plants perform photosynthesis with the help of sunlight. The amount of biomass or organic matter produced per unit area over a time period in plants during photosynthesis is called primary production

46.Which ones are the reservoirs of sulphur and carbon cycles respectively?

Atmosphere and consumers
Earth crust and atmosphere
Earth crust and producer
Atmosphere and predator
In sulphur cycle, the main reservoir is earth crust.
In carbon cycle, the main reservoir is atmosphere

47.What will happen if all the bacteria and fungi are destroyed?

There will be no disease and death
No antibiotics would become available
Dead bodies and excretions will pile up
Soil will become rich of all nutrients
As decomposers are the primary weapons to decompose the dead organic matter so, the extinction of the decomposers will severely destroy the nature as the dead remains in the nature will accumulate and they will not get decomposed.
The dead matter will not get decomposed and as a result the soil will not get the nutrients by the decomposition of dead matter and hence the soil will become infertile

48.In grazing food chain energy comes from

Organic remain
Air
Water
All of these
Sun.
A much less fraction of energy flows through grazing food chain in ecosystem terrestrial. Energy for the food chain comes from the sun. Food chain adds energy into the ecosystem

49.Choose the correct statements
I. Productivity is expressed in $gm^{-2} yr^{-1}$ or $kcal m^{-2}yr^{-1}$
II. The amount of biomass or organic matter produced per unit area over a time period in plants during photosynthesis is called primary production
III. Primary production is expressed in term of weight $g^{-2}$ or energy $kcal m^{-2}$
IV. Sugarcane have more efficiency to trap sunlight, so they accumulate more primary productivity
Choose the correct option

I and II
I and IV
I, II, III and IV
None of these
The rate of synthesis of energy containing organic matter by any trophic level per unit area in unit time is described its productivity. It is measured as weight (e.g., $g/m^2/yr)$ or energy (e.g., $kcal/m^2/yr)$. The amount of energy accumulation in green plants as biomass or organic matter per unit area over a time period through the process of photosynthesis is known as primary productivity. Primary productivity is expressed in term of weight $(g^{-2})$ or energy $(kacl m^{-2})$. $C_4$-plants area more productive that $C_3$ plants. Sugar cane is most productive crop being efficient in trapping light

50.Trophic level of food chain having greatest amount of energy, is

Carnivores
Herbivores
Autotrophs
Omnivores
Biotic factors of ecosystem linked together for food and form a chain called food chain. The various steps in food chain are called trophic levels. According to pyramid of energy-the energy flows from one trophic level to next in one direction only.
According to law of thermodynamics, when energy transformed from one step to next step then some energy is liberated in the form of heat.
As the autotrophs (green plants) form the base of food chain, therefore, they have highest amount of energy.