31 Years NEET Previous Year Questions: Ecosystem - 3 - NEET MCQ

Pyramid of numbers in a g rassland ecosystem is always upright. For most ecosystem, like grass and ecosystem. Pyramids of numbers are upright because numbering of organisms decrease at successively higher trophic levels. Trophic level refers to the organisms, position in the food chain.

Detritus food chain being with dead organic matter with dead plant parts, animals and their excretory product which is being acted upon by decomposers such as saprophytes to obtain energy needed for their survival.

Phytoplankton → zooplankton → Fish. This is a type of food chain in aquatic ecosystem. 

Soil is the uppermost weathered layer or earth's crust and is composed of  minerals and partly decomposed organic matter. Pedologist is a scientist who studies origin, composition and distribution of soil and the materials from which the soil is made. 

River water deposits alluvial soil. Alluvial soil- formed by the alluvium deposition by the rivers when they slowly lose their carrying capacity due to decrease in velocity. These consist of diverse ratio of sand, silt and clay. These the most widespread soil in India the entire northern plains as loamy soil. It contains roughly equal amount of sand silt and clay. It is more fertile than sandy soil.
Laterite soil-formed and hot wet tropical areas are formed by intensive and long lasting weathering of  underlying rocks and are rich in iron and aluminium.

German biologist Ernst Haeckel coined the  term 'ecology', the study of interrelationship between organisms and their environment. Ecosystem, consist of different communities of organism and the physical environment with which they interact. Phytogeography is the study of geographic distribution of plants species on earth.

Pyramid of  number represents the number of individuals on each tropic level.

The correct option is Option C.

Pyramid of number in a pond ecosystem is always upright, showing the number of individual organisms at each level. This number then shows a decrease towards apex, primary consumers are lesser in number than the grasses; the secondary consumers are lesser in number than the primary consumers.

Energ y pyramid can not be inver ted because energy always flows in one direction only. According to 10% law of energy transfer given by Lindemann (1972), during transfer of energy from one trophic level to other there is always loss in respiration and other activities only 10% of energy is transfered to neat trophic level. So the amount of energy flow decreases with successive trophic levels.

According to 10% law of Lindemann,if 1 tonne (1000kg) biomass is present in the grass, only 10% of it means 100 kg will go into deer and in tiger, the biomass will be only 10kg, i.g. 10% of deer' biomass.

An ecosystem is made up of biotic and abiotic factors. Biotic factors involves animals, plants, microorganisms. Abiotic factors involves temperature, air, water, land. Biotic community involves group of interacting populations. In a biotic community, the most important factor for survival of an animal is predators. They control the size of prey populations. They also increases the biodiversity by preventing a single species for being dominant.

Thus, the correct answer is 'Predators.'

First tropic level in a lake is phytoplankton, second is zooplankton.

Due to majority of phytoplanktons.

Succulent plants are fleshy xerophytes, which can grow in low water level area (desert). That is why, they are called as desert plants.

In submerged hydrophytes whole plant body remains under water. e.g.
Ceratophyllum and Utricularia. In these plants, stomata is absent and gaseous exchange takes place through general body surface.

The decomposers act on the dead organic matter and break them down into simpler compounds and minerals.

The primary succession means the development of communities only on a newly exposed habitat with no record of earlier vegetation.

The oceans cover about 2/3 of the whole surface of our earth.  Thus it is the most stable ecosystem, because of buffering action by water.

In a biotic community the herbivores (goat, deer) are those animals, which consume the primary producers (green plants). Hence they are primary consumers.

Biogeochemical cycles : Two types :
(a) Gaseous : Biogenetic materials involved in circulation are gases eg. N₂, O₂, CO₂ etc.
(b) Sedimentary : Biogenetic materials involved in circulation are non-gaseous eg. P₂, Ca, S etc. forms rocks.

So, the correct answer is 'Rann of Kutch'. Assertion :Rann of Kutch has breeding grounds for flamingos. Reason: Rann of Kutch is a natural reserve for wild ass also. The largest inland lake in India is situated in Rajasthan.

Producers are the direct and indirect source of  food for all the trophic levels. They are always more in number.

According to the 10% law, at each trophic level, only 10% of the energy received is transfered to the next trophic level.

Niche is a specific part of the habitat that is determined by the functioning of the population like shelter, type of food, season  etc.

The Gross primary productivity of an ecosystem is the total amount of organic matter produced by its producers, i.e. autotrophs. Coral reefs have maximum and deserts have the lowest productivity.