Question

In the desert there are plants that have adapted to the sparse rainfall by evolving mechanisms to store water. Cactus are an example of such a plant. You are studying a particular species of cactus in an area of desert that is 100 km^2. In your designated area of study you have counted 175 plants. What is the density of this type of cactus in terms of plants per square kilometer?

1. 571.4 plants/km^2
2. 0.571 plants/km^2
3. 1.75 plants/km^2
4. 0.00175 plants km^2

no explanations, just which number it is be quick thanks QUICK

In a population of wild geese there were 17 births and 62 deaths in the past year What is the growth rate of this population?

a) 1054

b) 45

c) -3.6

d) -45

Which of the following is NOT a correct statement concerning logistic population growth?

1. The carrying capacity is shown in the stationary phase.

2. Curve is shaped like S

3. Equilibrium is reached

4. Curve commences with fast growth

Answer 1

1) The density of this type of cactus in terms of plants per square kilometer is :-

(c) 1.75 plants/km^2

No. Of plants of cactus = 175

Area of the desert = 100 km^2

So, Density =   Number of plants of cactus Area of desert

=   175     plants/km^2 100

= 1.75 plants/km^2

2) The growth rate of this population :-

(d) -45

Birth rate = 17/ year

Death rate = 62/year

Growth rate = Birth rate - Death rate

= 17 - 62 = - 45

So the population have a negative growth rate of 45 ( -45).

So the correct answer is (d) -45 .

3) The incorrect statement concerning logistic population growth :-

(d) Curve commences with fast growth

The above statement is incorrect since the initial phase is slow. The fast growth or the exponential growth is seen in the second phase.

The other options are correct since :-

?When the graph is at the stable phase i.e. the resources are limited then the carrying capacity of the population has reached.

?At the carrying capacity the equilibrium has reached.

?Since there are 3 phases :- The initial slow phase then the acceleration phase where the population increases at fast rate and at last when carrying capacity is reached it shows a stable phase. Thus the curve is like S shaped.

So the statement which is incorrect (d) The curve commences with a fast growth.