Question

How do the following provide evidence in favour of evolution in organism? Explain with an example for each.

Answer 1

Answer:

The following are the various evidences in favor of evolution:

(a)Homologous organs: Organs with a common basic structural design but with different functions are said to be homologous organ. For example, forelimbs of a frog, lizard, bird and man.

The forelimbs of man are used for grasping, of lizard for running, of frog for propping up and bird for flying. They have different functions but have same structural pattern.

1)Frog

2)Lizard

3)Human

4)bird

(b)Analogous organs: The analogous organs have different basic structure but perform similar functions. For example, the wing of insects and the wing of birds, have a totally different anatomy and origin but they perform the same function of flying in air.

(1)wing of an insect

(2)wing of bird

(c)Evidences from fossils: The fossils also provide evidences for evolution. For example, the fossil Archaeopteryx looks like a bird but it bears a number of other features, which are found in reptiles. This observation provides a clue that birds have evolved from reptiles.

Answer 2

     These three provide evidence in favour of evolution in organism

↪  Homologous organ

↪  Analogous organ

↪ Fossils

Homologous organ :- they are the organ that are similar in structure but have been modified to perform different function.

↪ For example :-

forelimbs of humans, frog and lizard have similar structures. Frog uses it to hop and as a shock absorber, human use it to write, hold etc. and lizards use it to creep on walls.

↪ They explain may be the reptiles, mammals and amphibians had common ancestors and evolved to be in the present form.

Analogous organ :- They have different structure and appearance but perform similar functions.

↪ For example :-

↪ Wings of a bird and a bat have different structure as we have feather and wings all over the body on the other hand bat have thin flap like webbed wings but they perform function of flying.

↪ They do not show common ancestory but trace evolution due to which they  become capable of flying.

Fossils :- They are the remains of plants and animals found under earth that lived in remote past.

↪ They tell us about the evolutionary relationships in the past.

↪ For example:-

↪ Archaeopteryn has round cranium and wings similar to birds but claves and beak similar to reptiles.

↪ This shows relationship between reptiles an ares or may be ares evoluting from reptiles.