Q2 Page 158 - Chapter 9 Class 10 - Heredity and Evolution

In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better’ body design? Why or why not?

Answer:

• Bacteria is a primitive organism and has evolved over the years to survive in various extreme conditions.
• Fish, Spider, Chimpanzee etc. appeared on Earth much later, but they have also evolved to adapt to the environment better.
• But, it is not necessary that the new form of the organism is better adapted than the old form; the new organism may be a result of genetic drift (accident) or natural selection.
• On one hand, ‘progress’ can be seen in the complexity of these organisms .
• We can also see how less complex organisms like bacteria are present in all kinds of environments but not complex organisms like humans.
• Thus it is not possible to measure ‘progress’ or judge a ‘better body design’ on the basis of genetic complexity or evolution .