Topic like this will let you score more in AIPMT

Hello guys,

This time I am back with one of interesting and much more scoring topic in AIPMT and various medical entrance examination. Ecology and environment is one of the burning topic from where a lot of questions are being asked every year. Keeping in view the requirement of you guys, I came up with the collective information from the unit of ecology.

You guys must be wondering about which topic I am talking about. So, guys I am talking about the ecological pyramids.

The ecological pyramids are simply the representation of the trophic structure and also trophic function of the ecosystem. As we will move forward, we will realize that the producer form the base and the successive trophic successive tropic level at the apex.

In pyramids, basal, mid and top tiers show the parameter values for producers, herbivores and carnivores

There are three ways by which an ecological pyramid can be represented:

• Pyramids of number
• Pyramids of biomass
• Pyramids of energy

Pyramids of Number

This type of pyramid shows the number of individual organisms at each level.  That means, the number of individual organisms at different trophic levels of food chain. They show the relationship between producers, herbivores and carnivores at successive tropic levels in terms of their number.

These pyramids are mostly upright number of producers is maximum and number of herbivores and carnivores decrease towards apex or at successive trophic levels, such as grassland ecosystem and aquatic ecosystem.

Pyramids of Biomass

The Pyramid of Biomass is a graphical representation that shows the extent of biomass per unit area within different trophic levels in an ecological system. The bottom level of the representation is usually occupied by the producers whereas the carnivals are shown in the top levels.

In Pyramid of biomass, the energy capacity is usually concentrated at the base. This represents at being wide and decreases as one moves up to the apex.

Mostly these pyramids are also upright (erect). For e.g., Tree ecosystem and forest ecosystem. When we observe pyramids of biomass in aquatic ecosystem is inverted because in it producers are micro-organisms and their biomass is very less.

If we talk about grassland, the biomass of the grasses is maximum, and it gradually decreases towards the consumer level. Such inverted biomass pyramids occur because the producers—phytoplankton—grow, reproduce, and are consumed so quickly by the zooplankton that they never develop a large population size, or standing crop.

Pyramids of Energy

The energy pyramid is a graphical model which depict the flow of energy in a community. Different groups of organisms represent that they might compose a food chain at different levels.

When you will observe it from bottom towards upward, they will be as follows:

• Producers
• Primary consumers
• Secondary consumers
• Tertiary consumers

Now you will ask, who come this pyramid shape?

Guys, if you remember the conversion of fuel (carbohydrate) into energy (ATP) !

Absolutely right! Some of the energy to fuel various life processes at each level. So, there is gradual decrease in energy at successive trophic levels.

In 1942, Raymond Lindenman proposed a law (10% Law of Lindenman) which states that, during the transfer of energy from organic food from one trophic level to the next, only10% of energy from organic matter is stored as flesh.

From above references, we came to know that the consumers at the top of a food pyramid, as a group, thus have much less energy available to support them than those closer to the bottom. That’s why their numbers are relatively few in most communities. Eventually, the amount of useful energy left can’t support another level. That’s why energy flow is depicted in the shape of a pyramid. The energy that enters a community is ultimately lost to the living world as heat.

So guys, I am sure you got the basic understanding of what ecological pyramids are and how they are linked with various ecosystems.

Well! I am Aabid Hussain, faculty member and your biology mentor from askIITians. Our priority is the quality education and we are always committed to that.

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See you guys next time with something value worthy and things to know. Till then, take care.