Chapter 9: Heredity and Evolution- Exercise- 6

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Chapter 9: Heredity and Evolution

Class: X

Exercise number 6

 

Question 1

Why are human beings who look so different from each other in terms of size, colour and

looks said to belong to the same species?

Answer 1

All human beings are single species originated from Homo sapiens, who are believed to be the primitive members of human beings. There had not been well set boundary for the geographical or reproductive isolation between the different members of the human species. Over a period of time, it resulted in several genetic makeups of traits with small variations. That is why all human beings who look so different from each other in terms of size, colour and looks said to belong to the same species.

Question 2

In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees

have a ‘better’ body design? Why or why not?

 

Answer 2

No, evolution cannot be associated with better body designs. Evolution creates more complex body design but it does not mean that the simple body designs are inefficient. Bacteria in spite of having simple body design can survive extreme conditions where other organisms cannot. At the same, a chimpanzee has strong limbs and is capable of multiple actions. That means there is no better body design.