Read the following statements regarding ecological pyramids and choose the correct answer.
a. The relationship between organisms at different trophic levels is expressed in terms of number, biomass and energy.
b. Any calculations of energy content, biomass or number has to include one group of the organism at that trophic level.
c. In most ecosystems, all the pyramids of number, biomass and energy are upright.
d. The pyramid of biomass in the sea is generally inverted.
e. Pyramid of energy is always inverted and can never be upright.
An ecological pyramid is expressed in terms of number, energy, and biomass.
Among the following statements regarding ecological pyramids, statements (b) and (e) are wrong
Detailed Solution: Ecological pyramid is a graphical representation of the relationship between organisms at different trophic levels. The pyramid is expressed in terms of number, energy, and biomass.
Any calculations of energy content, biomass or number have to include all groups of organisms at that trophic level.
In most ecosystems, all the pyramids of number, biomass and energy are upright as the producers mainly have high numbers, maximum biomass and thus greater energy and it decreases as we move from producers to higher trophic levels.
In some ecosystems, the pyramid of number and the Pyramid of Biomass is inverted. For example, the pyramid of biomass in the sea is generally inverted.
However, the pyramid of energy is always upright and never inverted.
Thus, the correct answer is Option (c) - (b) and (e) are wrong.
The correct option is C) Statements b and e are wrong.
Statement b
While calculating energy content or biomass, all organisms at that trophic level have to be considered. Calculations performed by considering a few organisms can not be true.
Hence, the statement in option (b) is incorrect.
Statement e
The pyramid of energy can't be inverted and is always upright as the energy of the lower trophic level is more than that of the higher trophic level.
Hence, the given statement in option (e) is incorrect.
Therefore, the correct answer is option c.
Ecological succession is the steady and moderate change in a species of a given area with respect to the changing environment. Our nature consists of both biotic and abiotic factors. When these biotic and abiotic factors interact with each other to develop natural communities they give rise to such successions.
When land is left on its own for years, it starts being occupied by microorganisms followed by wild shrubs and other large plants, which gives rise to a new ecosystem. The series of stages is quite predictable and inescapable. In order to understand the primary and secondary succession, we need to be very much clear about what ecological succession is as they are its types. This succession mainly focuses to bring about equilibrium in the ecosystem. When the target is achieved, it is called a climax community.
The number of species to survive is then decided based on achieving the equilibrium. In a community, these changes happen in a sequence, and such a community is known as a seral community which further is an intermediate stage of ecological succession advancing towards the climax community. All the succession begins with an instigating species. The instigate species or the first species build an initial biological community that is simpler in form. The initiation of this ecological succession separates it into the following three types –