Class 12th Biology 2015 Set3 Delhi Board Paper Solution
Question 13
Explain the interpretation of Charles Darwin when he observed a variety of smallblack birds on Galapagos Islands.
Answer
Charles Darwin observed a variety of small black birds called finches. By observing their characteristics on the Galapagos Islands, he proposed his famous theory known as the 'theory of natural selection'.
In this theory, he gave the following postulates:
All organisms possess an enormous power of fertility. Food, space and resources are limited. There is a struggle for the existence within a species as well as between two different species. Nature will favour the survival of the fittest. No two individuals will be exactly identical except identical twins. Some variations will always exist. Darwin believed that variations will ultimately lead to the formation of new species.Popular Questions of Class 12th biology
- Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- Q:- What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Explain the Law of Dominance using a monohybrid cross.
Recently Viewed Questions of Class 12th biology
- Q:- Can you think and answer how a reporter enzyme can be used to monitor transformation of host cells by foreign DNA in addition to a selectable marker?
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- Which is a better mode of reproduction sexual or asexual? Why?
- Q:- Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?
- Q:- Is sex education necessary in schools? Why?
- Q:- What is pedigree analysis? Suggest how such an analysis, can be useful.
- Q:- Two heterozygous parents are crossed. If the two loci are linked what would be the distribution of phenotypic features in F1 generation for a dihybrid cross?
- Q:- Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?
- Q:- Find out through internet and popular science articles whether animals other than man have self-consciousness.
- Q:- Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.