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(a) What is the difference between Darwinian and Lamarckian theories of evolution?
(b) What is meant by the following terms? Give an example in each case.
(i) Homologous structures.
(ii) Analogous structures.
(iii) Vestigial structures.

Answer Text:
a)- In Lamarckian theory, inheritance of acquired characteristics/ environment induces production of inheritable character which is then inherited.
- In Darwinian theory, inheritance of genetically acquired characteristics/character happens to appear spontaneously which then gives advantage
to organisms and therefore better adaptable characters are then inherited by natural selection.
b)
i)- Structures that have common basic plan and have a common embryonic origin and are modified to perform different functions.
Examples: vertebrate forelimb/pretadactyl limb, beaks of bird, mouth parts in insects.
ii)- Structures with different structural plan and different embryonic origin but evolve to perform similar functions. Example: wings of
insect, wings of bird.
(iii) - Structures that are greatly reduced in size and therefore cease to function. Examples : human appendix, kiwi (flightless bird) with reduced wings,
vestigial wings in flies, human hair,presence of hind limbs in python,reduced pelvic girdle in whale.