Question

(Q2) What will be the effective population size in a panmictic population of 240 with 200 females and 40 polygamous males? Please explain.
(A)160 (B)133 (c) 63 (D) 67

Answer 1

from Wikipedia:
When the sex ratio of a population varies from the Fisherian 1:1 ratio, effective population size is given by:

N_e^{(v)} = N_e^{(F)} = {4 N_m N_f \over N_m + N_f}

Where Nm is the number of males and Nf the number of females. For example, with 80 males and 20 females (an absolute population size of 100):

N_e = {4 \times 80 \times 20 \over 80 + 20}
={6400 \over 100}
= 64

Again, this results in Ne being less than N.