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Frequently Asked Questions

Q1. What is the difference between interspecific and intraspecific struggle for existence?

Answer: Interspecific struggle is the struggle between the unrelated species, for example,

a snake wants to eat a rat but the rat tries to escape from the snake. Whereas, intraspecific

struggle is the struggle between the members of the same species. As the food material and area

of living are limited, the individual who grows in right direction survive while the other will

perished.

Q2. Critically evaluate the fourth postulate of Lamarckism.

Answer: The fourth postulate of Lamarckism is also known as the theory of inheritance

of acquired characters. According to this theory, all changes that organism acquire during the

lifetime are transmitted to the next generation. This theory has been severely criticized because

of the fact that it has not been possible to establish that characters acquired during the lifetime of

any organism are transmitted to the succeeding generation.

Q3. What is use and disuse theory?

Answer: Theory of use and disuse is the third postulate of the Lamarckian doctrine.

According to this theory, the development of organ is directly proportional to its use; continuous

use strengthens the organ while disuse has reverse effect. Lamarck cited the lengthening of neck

in the giraffe due to its continuous use in reaching to the leaves and fruits of high rise tree and

the occurrence of vestigial organs such as Pinna, Simi lunar membrane, vermiform appendix etc.

in man due to its constant disuse.

Q4. What is natural selection theory?

Answer: Natural Selection theory is the theory propounded by Charles Darwin describing

the causes of organic evolution. The concept of this theory is that, in the face of the struggle for

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existence, only those organisms that are most well adapted to the environment can survive. Thus,

natural selection of organisms take place in which nature eliminates those that are not fit by way

of several natural calamities and preserves those that are fit.

Q5. What are the drawbacks of Darwinism?

Answer: Some of the important drawbacks of Darwinism are:

1. It does not account for presence or origins of variations among living organisms. In tryingto solve this problem, Darwin was inclined to fall back upon Lamarcks theory of Acquired

characters, which has been disproved.

2. Natural selection cannot carry a species beyond its natural range of variability. This isbecause variation is a progressive course in evolution which causes modification, but

heredity acts as a conservative force that tends to preserve the variations as such.