A typical population growth curve of a species show 5 phases. They are Lag phase, Exponential phase, deceleration phase, Stable phase and Death phase. which can be seen in Figure 17.10 on page 382 of your textbook. Take a look at these phases and recognize the difference between them.
Then, turn to Page 386 of your text and locate Figure 17.14. Study the behavior of human population growth over the past 10,000 years. You will notice that during the Agricultural Society, basically for more than 9000 years, the human population growth was minimal and there was not significant growth rate then. However, from the beginning of the Industrial society the human population growth has been steady with exponential rate of increase.
I would like you to focus on the probable reasons for the display of this growth behavior and answer the following questions for this growth curve, below:
1. Why the lag phase of human population growth lasted for a long time? Give reasons.
2. What are the reasons for the occurrence of the exponential phase of human population growth during the past 300 years?
3. Is there going to be, in the future, a stable equilibrium phase for the human population growth on earth? Give reasons.