(a) Explain the terms ‘analogous organs’ and ‘homologous organs’ with examples. (b) In what way are analogous organs evidence for evolution?
(a) Explain the terms ‘analogous organs’ and ‘homologous organs’ with examples.
(b) In what way are analogous organs evidence for evolution?
(a) Analogous Organs: Organs which performs similar function but are different in structure and origin.
Example: wings of a bird and wings of an insect.
Homologous Organ: Organs which have different functions but similar structure and origin.
Example: fore arm of frog, lizard, bird and human.
(b) The presence of analogous organs indicates that even the organisms having organs with different structures can adapt to perform similar functions for their survival under hostile environmental conditions. Thus, the presence of analogous organs in different animals provide evidence for evolution by telling us that though they are not derived from common ancestors, they can still evolve to perform similar functions to survive, flourish and keep on evolving in the prevailing environment.
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Define ‘natural selection’. (b) “Only variations that confer an advantage to an individual organism will survive in a population”. Do you agree with this statement? Give reason for your answer.
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What do you understand by the term ‘evolution’? State Darwin’s theory of evolution.
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Bacteria have a simpler body plan when compared with human beings. Does it mean that human beings are more evolved than bacteria? Explain your answer.
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