Question

Why are there few tertiary consumers in any ecosystem? and Why are these consumers most likely to suffer from impacts due to pesticides in food chains?

Answer 1

Answer :-

A tertiary consumer, after the manufacturers, primary consumers and secondary consumers, is a fourth trophic category. Tertiary consumers are their main food source, feeding primary and secondary consumers.

A tertiary consumer can sometimes eat several different animals in the real world, and even plants. That means they can be carnivorous or omnivorous too. Some tertiary consumer examples include the prey birds, big cats, and foxes.

Chemical pesticides are chemicals that are sprayed onto crops to destroy species that can reduce the growth of plants, such as weeds, insects and fungi. Weeds compete for space with the crop plants, fungi can cause plant diseases, and insects can eat and destroy the plants.
Pesticides have harmful environmental effects if they are not biodegradable, as they can spread over time in the species.
Because the animals tend to eat tons of species from the level below in the food chains, the content of pesticides in the organism bodies increases at higher food chains levels.
This may contribute to pollutant toxicity reaching lethal levels in the species at the top of the food chain. The build up of toxic substances is known as bioaccumulation in living organisms.
The insecticide DDT used in the 1940s to kill mosquitoes is an example of a non-biodegradable, or permanent, pollutant. Because it is not very soluble in water, it accumulates in body tissues so it can not be excreted.
DDT concentration in farmers is very low, but rises dramatically in the food chain at higher levels. This can cause consumers at the top level such as ospreys to lay eggs with much thinner shells which are more likely to break.