Question

(a) In a pond there were 200 frogs. 40 more were born in the year. Calculate the birth rate of the population.

(b) Population in terms of number is not always a necessary parameter to measure population. Justify with two examples. [3]

Answer 1

(a) No. of Frogs in a Pond = 200
No. of frogs born in a year = 40
Total number of the frogs = 200 + 40 = 240 [1]

$\mathrm{Birth}\mathrm{rate}=\frac{\mathrm{No}.\mathrm{of}\mathrm{births}}{\mathrm{Total}\mathrm{population}}\times 100=\frac{40}{240}\times 100=16.66\%$
(b)

1. In an area with 200 Parthenium plants and a single huge banyan tree, the role played by a single banyan tree is much greater even though the population density of the banyan tree is comparatively lower than Parthenium plants. Hence, in this case, calculating biomass is a better way to measure population size. [1]
2. The tiger census is calculated based on pug marks and fecal pellets. [1]