Test: Ecology (March 12) - NEET MCQ

Ecosystem consists of biotic component producer, consumer and decomposer. Producer fix solar energy into useable forms and decomposer breaks the complex organic matter into simpler forms but consumer do not perform specific function so non-essential.

Urbanization means the increasing number of people that live in urban areas due to shifting from rural areas to urban areas. It affects the population density and leads to more loss of flora and fauna since more space for residence is occupied by humans.

The on-site or the protection and conservation of species (genetic resources) in their natural habitat (populations of plant or animal species) is called in-situ conservation. Areas such as biosphere reserves, national parks, and wildlife sanctuaries are the places were in-situ conservation is done.

The chemical energy of food is the main source of energy required by all living organisms. This energy is transmitted to different trophic levels along the food chain. This energy flow is based on two different laws of thermodynamics:

• First law of thermodynamics, that states that energy can neither be created nor destroyed, it can only change from one form to another.
• Second law of thermodynamics, that states that as energy is transferred more and more of it is wasted.

When a graph is drawn to compare the relationship between species richness and area for wide variety of texa, the graph appears to be a rectangular hyperbola.

The off-site or the protection and conservation of species (genetic resources) outside their natural habitat (populations of plant or animal species) is known as ex-situ conservation. Areas such as botanical gardens, zoos, Gene banks, Tissue culture banks are the places were ex-situ conservation is done.

If all members fo a host species die the parasite that obtain their food from the particular host also die off due to lack of food. This represent co-existence of species.

When we will move away from the equator towards poles there is a gradual decrease in the species diversity. This is because climatic condition becomes gradually adverse as we move from equator to poles.

Decomposers breaks the complex organic matter present in dead plants and animals into simpler form that can be reused. They acts as reducer of dead and decaying matters.

Primary productivity is the rate at which solar energy is converted and stored by the producers per unit area over a time period. It involves the conversion of solar energy into organic substances by photosynthetic and chemosynthetic autotrophs.

India has about 50,000 type of rice and 1000 types of varieties of mango. This thigh level of diversity indicates very high genetic diversity and one of the largest in the world.

For greater efficiency a food chain must have three to four trophic levels. At each trophic levels loss of energy is very high so very small amount of energy is left after there trophic level.

A detritus food chain begins with dead organic matter. It is made of decomposers which are heterotrophic organism fungi and bacteria.Rhizophora species is a saprophyticheterotrophs.

Species area relationship is the relationship between the area and the particular habitat. It is dependent on immigration, extinction and clustering etc. It was first studied by Alexander Von Humbolt.

Food web is formed by interaction between a numbers of food chains having common members. Stability of ecosystem largely depends upon the kinds of food web exists in it for proper flow of energy.