BIOLOGY M.C.Q (1 Marks)

1. Fishes.

1. Open; can.

1. Solar radiation/ light

Explanation:

Of the incident solar radiation, less than 50 percent of it is photosynthetically active radiation (PAR). Plants are only able to capture 2-10 percent of PAR. Therefore solar radiation/ light is the limiting factor in the primary productivity of the ecosystem.

3. Phytoplankton → Zooplankton → Fish.

3. Phosphorus cycle.

4. Gene flow does not occur between the populations of a species.

3. Real basic units of classification.

3. Lichens

Explanation:

Lichens are considered as pioneer species in primary succession on rocks because they can easily grow on rocks where other plants cannot grow. They produce oxalic acid which induced the weathering of rocks and thus soil is formed. When these lichens die they increase the soil fertility so other plants can grow and start the chain reaction.

1. Biomass pyramid of aquatic system

Explanation:

Pyramid of biomass represents the amount of biomass at the various trophic levels. Pyramid of biomass is upright, except in aquatic food chain involving short-lived planktons when biomass at any given one time will be less than consumers at the higher level.

3. Mineral movement will be blocked.

1. Organic matter

Explanation:

The rate of production of total organic matter during photosynthesis is called the gross primary productivity. It is also equal to the amount of carbon fixed during photosynthesis by all producers in that particular ecosystem.

2. Moderate percentage of young individuals

2. Secondary productivity

Explanation:

The rate at which consumers like rabbit in a grassland convert the chemical energy of their food into their own biomass is called secondary productivity. The efficiency at which energy is transferred from one trophic level to another is called ecological efficiency.

2. Pyramid of standing crop aing crop.

2. 10%.

2. Phosphorus cycle

4. A tree should be planted in place of one to be cut.

3. Desert.

Desert ecosystem is expected in an area where evaporation exceeds precipitation, and means annual rainfall is below 100mm.

4. Fresh weight.

2. Fungi.

3. Rock

Explanation:

The natural reservoir of phosphate is the rock which contains phosphorus in the form of phosphates when rocks are weathered, minute amounts of these phosphate dissolve in soil solution and are absorbed by the roots of the plants. Herbivores and other animals obtain this element from plants.

3. ii and iv.

4. (i) and (iii).

3. ii and iii.

Decomposers depend on other organisms for food, hence they are heterotrophs. They obtain nutrients by decomposing the detritus and hence are called saprotrophs.

2. Desert.

4. Newly-exposed habitat with no record of earlier vegetation.

3. Biogeochemical cycle

4. Gross primary productivity.

2. Energy

Explanation:

Pyramid of energy is ecological pyramid, that represents the flow of energy from one trophic level to the next a lot of wastage occurs in metabolism and energy transfer. Maximum energy content is present in producers and least at top carnivore levels.

2. Climax community

Explanation:

Ecological succession is the process of change in the species structure of an ecological community over time. The community begins with relatively few pioneer plants and animals and gradually develops stable or self-perpetuating species as a climax community.

1. Producers.

2. Soil.

1. Function at its place of occurrence.

1. Primary producers

Explanation:

Because primary producer first requires CO₂, for the process of photosynthesis by which they make their food.

1. Psammosere

Explanation:

Primary succession can happen when bare sand is colonised by plants. Over time, the sand builds up into sand dunes, raising the ground above the height of sea level. Succession in sand dunes is sometimes called a psammosere.

2. Tropical rain forests.

Tropical rain forests have high population density of green plants. Hence, net primary productions are maximum in such conditions.

2. Atmosphere.

2. Pond

Explanation:

Ponds are generally shallower with depth less than 2 meters. Hence, the pond has good light penetration, which in turn leads to more photosynthesis and increased biomass and consequently rich diversity of organisms.

1. Derived from living things

Explanation:

Abiotic resources are non-living while biotic resources are living. Soils, rocks, and minerals are abiotic but plants and animals are biotic resources.

2. Leaching.

1. Always upright

Explanation:

Pyramid of energy is always upright, can never be inverted, because the energy always flows from a particular trophic level to the next trophic level. The amount of available energy decreases during transfer from one trophic level to another. So, as we go from the first trophic level to the top trophic level, the amount of available energy becomes less and less.

3. Tropical rain forest.

4. Ocean.

1. Benthonic and brown algae.

2. Elton

Explanation:

An ecological pyramid is a graphical representation to describe the number of organisms, energy relationships, and biomass of an ecosystem. They are also called as Eltonian pyramids after Charles Elton, who developed the concept of ecological pyramids.

1. Inverted

2. Gause’s hypothesis.

4. Anabaena.

1. Phytoplankton

Explanation:

Primary production is the synthesis of food through the process of photosynthesis, which uses light as its source of energy. The primary production in the ocean is performed by free-living microscopic organisms called phytoplankton. Larger autotrophs, such as the sea grasses and seaweeds are generally confined within the photic zone. The majority of free-floating production takes place within microscopic organisms (phytoplankton)

4. Faecal matter.