Chapter 4, Problem 33A

Summary Introduction

To analyze:

Phase of growth occurred between the Old Stone Age and the Middle Age

Introduction:

Old Stone Age: The Stone Age begins 2.6 million years ago when human society was largely dependent on foraging, hunting, and fishing for their food. Stone tools used for hunting and, the domestication of animals and farming practices not started in this Age.

Middle Age: This is the period in human evolution when they already aced in plowing, irrigation for farming. Agriculture and domestication increased the human food supply which decreased the death rate resulting in a gradual increase in population.

Explanation of Solution

In a growth curve, in the beginning, the number of organisms increases gradually but at a slow pace. This slow growth phase is known as the Lag phase.

In reference to graph, the Lag phase occurred between the Old Stone Age and the Middle Age.

The population growth rate mainly depends on the Birth rate, Death rate, and all the biotic and abiotic conditions of the habitat. The time period in the question has a higher Death rate and harsh climatic condition in comparison to the present condition.

Conclusion

At the beginning of the Stone Age, harsh climatic conditions and limited resources of food kept the size of the population at a relatively constant number, but from the beginning of the Middle Age, living conditions improved which contributed to lower Death rate and higher Birth rate.