(a) Why the plants that inhabit a desert are not found in a mangrove? Give reasons.

(b) Heat loss or heat gain depends upon the surface area of the organism’s body. Explain with the help of a suitable example.

OR

(a) Write the exponential equation for J-shaped growth form.

(b) What is the advantage the organism have in association between cattle egret
and cattle?

(a) The plants found in desert are not found in mangrove, reasons are:
1. Desert plants leaves are reduced into spine.
2. Desert plants have sunken stomata to reduce water loss through transpiration
3. Desert plants also have roots grow deeply to explore possibility of underground water.
4. Cuticle layer on stems to preserve moisture.
5. Mangrove has salty condition, plant have pneumatophores specialised root which grow negatively geotropic
6. Mangrove plants leaves are thin, small and green. Stems are usually cuticularised.

(b) Small animals have a large surface area relative to their volume and they lose body heat very fast during cold conditions. More energy is required to generate body heat through metabolism. Smaller animals are rarely found in Polar Regions.

OR

(a) Exponential equation for J-shaped growth form is
Where, dN/dt is the rate of change in population size,
‘r’ is intrinsic rate of natural increase and
‘N’ is the population size.

(b) In this association, the cattle egret gets food easily thus benefited while the cattle has no benefit nor harmed (+, 0)