Identify the statements which are correct.
1. Darwin proposed the theory of evolution by natural selection, where species evolve over time due to advantageous traits being passed on to the next generation.
2. Lamarck’s theory suggested that acquired traits during an organism’s lifetime cannot be passed on to the next generation.
3. Thorns of Bougainvillea and tendrils of Cucurbita represent homology.
4. The eye of the octopus and the eye of mammals are examples of analogous structures, as they perform similar functions but are not anatomically similar.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 1, 3 and 4 are correct.
True. 1. Darwin proposed the theory of evolution by natural selection, where species evolve over time due to advantageous traits being passed on to the next generation. Darwin said that heritable variations that help some individuals use resources better let them leave more progeny. Over generations, new forms arise.
False. 2. Lamarck’s theory suggested that acquired traits during an organism’s lifetime cannot be passed on to the next generation. Lamarck said the opposite: characters acquired by use and disuse, like the giraffe’s long neck, are passed on.
True. 3. Thorns of Bougainvillea and tendrils of Cucurbita represent homology. The thorn and the tendril come from the same basic structure but do different jobs. This is divergent evolution.
True. 4. The eye of the octopus and the eye of mammals are examples of analogous structures, as they perform similar functions but are not anatomically similar. Analogous structures do the same job but differ in structure. They result from convergent evolution.
Statements 1, 3 and 4 are correct.
NCERT Extract:
Biological Evolution – “… The novelty and brilliant insight of Darwin was this: he asserted that variations, which are heritable and which make resource utilisation better for few (adapted to habitat better) will enable only those to reproduce and leave more progeny.”
Biological Evolution – “Even before Darwin, a French naturalist Lamarck had said that evolution of life forms had occurred but driven by use and disuse of organs. He gave the examples of Giraffes who in an attempt to forage leaves on tall trees had to adapt by elongation of their necks. As they passed on this acquired character of elongated neck to succeeding generations, Giraffes, slowly, over the years, came to acquire long necks.”
What are the Evidences for Evolution? – “… In plants also, the thorn and tendrils of Bougainvillea and Cucurbita represent homology (Figure 6.3a). … They are not anatomically similar structures though they perform similar functions. Hence, analogous structures are a result of convergent evolution – different structures evolving for the same function and hence having similarity. Other examples of analogy are the eye of the octopus and of mammals or the flippers of Penguins and Dolphins.”