Question

Explain how exponential growth works and provide an example of a species whose population undergoes exponential growth.

a) Exponential growth is when a population multiplies at a constant rate. Example: Bacteria.
b) Exponential growth is when a population adds a fixed number of individuals. Example: Elephants.
c) Exponential growth is when a population decreases rapidly. Example: Dodo birds.
d) Exponential growth is when a population remains constant. Example: Sharks.

Answer 1

Exponential growth in biology refers to when a population's growth rate increases as the population size gets larger, resulting in a rapid increase of individuals. Bacteria in a flask with unlimited nutrients is a classic example, where the population can double with each hour. However, in natural environments, exponential growth is tempered by limited resources and other factors, leading to logistic growth instead.

Step-by-step explanation:

Exponential growth occurs when a population's growth rate increases over time, proportional to the size of the population. Under ideal conditions with unlimited resources, this can lead to a rapid multiplication of individuals within the population. The classic example of exponential growth is observed in bacteria, which reproduce through prokaryotic fission at fast rates when conditions are favorable.

Considering a population of 1000 bacteria in a flask with an abundant supply of nutrients, after one hour—assuming no mortality and that each bacterium divides once—the population would double to 2000. After another hour, these 2000 bacteria would divide again, amounting to 4000. The significant aspect of exponential growth is that with each reproductive generation, the number of organisms added is larger than the last, hence the growth rate accelerates. The pattern of growth continues to increase rapidly producing a J-shaped curve on a graph when population size (N) is plotted against time.