Question

What was the most significant trend in the evolution of modern man (Homo sapiens) from his ancestors?
A. Upright posture
B. Shortening of jaws
C. Binocular vision
D. Increasing brain capacity

Answer 1

Hint: During the course of evolution from primates to modern man, many changes took place at every stage such as in posture, jaws, forehead, limbs, brain capacity, their habits etc. These changes made every stage more advanced than earlier stages.

Complete Answer:
The cranial capacity at every stage of human evolution went on increasing. This was the greatest sign of the evolution of modern man. The cranial capacity of modern man is almost twice that of chimpanzees.

The evolution of modern man from its ancestors took place as follows:
Dryopithecus-> Ramapithecus -> Australopithecus -> Homo erectus -> Neanderthal man -> Cro-Magnon man -> Modern man.

- Earlier apes had a cranial capacity of 400 – 600 c.c. whereas the cranial capacity of human beings is 1450 c.c. Human beings during their course of evolution also developed articulated speech which was absent in apes and primates indicating evolution.
- In the origin of man, there are four main stages, such as Ape – stage, Ape – men stage, Primitive men or the prehistoric man stage and modern men stage. The stages from Dryopithecus to modern man come under the modern man stage.
- Homo habilis was the first human – like being the hominid. Their cranial capacity was 650 – 800 c.c. They were also called handymen or tool makers because they made tools from stones.
- The next stage called Homo erectus was the first true man, they are divided into two men as Java man and the peking man. Java man had a cranial capacity of around 940 c.c. and the cranial capacity of peking man was between 850 c.c.to 1200 c.c.

- The java man was about five feet in height and walked erect, they had a prognathous face with massive jaws and huge teeth. There was no chin and a bony eyebrow ridge was present.
- The peking man was similar to java man and they had heavy bony eyebrow ridges with a low slanting forehead and no chin. But their cranial capacity was greater than java man.

- The next stage , that is the neanderthal man, was considered as an advanced prehistoric man. Their cranial capacity was 1450 c.c. which is almost equal to modern man. They were quite intelligent and they were the first to perform ceremonies and bury the dead bodies along with their tools.

- Cro – magnon man had a large skull with the cranial capacity of 1600 c.c. Their face had a chin and a round forehead, along with a narrow nose and thin eyebrow ridges. They used to live in caves with their families.

Hence the correct answer is option D.

Note: Not everything changed between the ape and man during the course of evolution, there are certain characteristics which are similar to both such as, Both had the absence of tail; broad chest because the sternum got flattened; their molar teeth with five cusps and both are capable of sound production.