Explain the technique used to estimate the population size of a named species of organism that is able to move.

a. named species ✔ Do not award marks for group of animals eg birds. Do not award the mark for this point if the method doesn’t apply for the species.

b. capture and count a sample of the population ✔

c. example of method of capture ✔

d. apply a mark that will not affect the survival of the animal «e.g. non-toxic paint spot/ear tag/leg ring/radio transmitter» ✔ OWTTE

e. release the organism into the environment ✔

f. allow time to become randomly dispersed ✔ OWTTE

g. capture «a second sample» and count the complete sample ✔

h. count the marked individuals in the second sample ✔

i. define formula to estimate the population size ✔ $N=\frac{{\text{n}}_1\times {\text{n}}_2}{{\text{n}}_3}$ where n₁ = first capture, n₂ = second capture, n₃ = number marked in second capture.
Accept alternative displays of formula, e.g. different variables, wording displayed in a formula, etc.

j. only estimates could be obtained ✔