The graph below shows species –area relationship.
(A) If b denotes the relationship on log scale
i) Describe a and b.
ii) How is slope represented? Give the normal range of slope. iii) What kind of slope will be observed for frugivorous birds and mammals in a tropical forest?
(B) Species diversity of plants (22%) is much less than that of animals (72%). Analyze the reasons for greater diversity of animals as compared to plants.
OR
(a) Which of the above represents the increase or decrease of population?
(b) If N is the population density at time t, then what would be its density at time? Give the formula.
(c) In a barn there were 30 rats. 5 more rats enter the barn and 6 out of the total rats were eaten by the cats. If 8 rats were born during the time period under consideration and 7 rats left the barn, find out the resultant population at time.
(d) If a new habitat is just being colonized, out of the four factors affecting the population growth which factor contributes the most?
i) a: S=CAz
b: log S = log C+ Z log A
where,
S= Species richness A= Area
Z = slope of the line (regression coefficient)
C = Y-intercept
ii) Slope is represented by Z which is the regression coefficient. The normal range of slope is 0.6-1.2
iii) For Frugivorous birds the slope Z would be 1.15.
(B)
1. Animals can move hence can avoid predators and move to a more favorable spot.
2. They have well developed nervous system. They can respond to stimuli in a far better manner.
OR
(a) Label ‘a’ and ‘d’ represent increase in population.
Label ‘b’ and ‘c’ represent decrease in population.
(b) If N is the population density at time t, then density would be:
N t+1 = N t + [(B + I)- (D + E)]
(c) We have,
N t=30;
I=5;
E=7
D=6
B=8
Putting the value in
N t+1 = N t + [(B+I) - (D + E)] N t+1
=30+ [(8+5)-(6+7)] =30+ [13-13]
=30+0
=30 rats
(d) The four factors which affect population growth are:
1. Birth rate
2. Mortality rate
3. Immigartion
4. Emmigration
If a new habitat is just being colonized, out of the four factors Immigration (is the movement of people in the colony) affecting the population growth factor contributes the most