Question

The usual shape of growth curve is-
a. Sigmoid
b. Zigzag
c. Linear
d. Inverted bell-shaped

Answer 1

Hint: The growth curve is usually used to show an increase or change in a population over time. It rises with the time and forms a curve. As the population stabilizes it decreases to zero. It does not show a steady curve as the growth of a population may change or differ over time.

Complete answer:
S-shaped growth curve or sigmoid growth curve is a pattern of growth. In a new environment, the population density of an organism increases slowly initially over time, in a positive acceleration phase. This then increases rapidly while approaching an exponential growth rate as in the J-shaped curve; but then it declines in a negative acceleration phase until at zero. This is when the growth rate of a population stabilizes.

Hence, The correct answer is option (A).

Additional information:
A growth curve is a graphical representation of an increase in population over time. Growth curves are widely used in statistics to determine the type of growth pattern of the quantity. It can be linear, exponential, or cubic depending upon the fragment of population given. An example of a growth curve is a country's population over time.

The growth curve represents the growth of a particular population over a span of decades. This shape of a growth curve is considered to be an exponential growth. Here the growth curve begins slowly, remaining nearly flat for some time and before increasing swiftly as to appear almost vertical.

Note: As competition increases and resources become increasingly scarce in a population, the carrying capacity (K) is reached in their environment, causing their growth rate to slow down nearly to zero. This gives a S-shaped curve of population growth, also known as the logistic curve.