Match the terms given in column I with those given in column II :
(i) – c.
(ii) – b.
(iii) – e.
(iv) – a.
(v) – d.
(a) If a normal human cell has 46 chromosomes, how many chromosomes will be there in a human (;) sperm cell, and (ii) zygote ?
(b) What sizes of plants are produced if both parents have genes Tt ?
a) Name the scientist who gave the theory of origin of life on earth. What is this theory ?
(b) How are those species which are now ‘extinct’ studied ?
How are fossils formed? Describe, in brief, two methods of determining the age of fossils. [All India]
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Why or why not ?
Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement ? Why or why not ?
Explain with examples how the following are evidences in favour of evolution in organisms. (i) Homologous organs (ii) Analogous organs (iii) Fossils [Delhi]
Give an example of body characteristics used to determine how close two species are in terms of evolution and explain it. [All India]
If the trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier ?
(a) What is the genotype of dwarf plants which always produced dwarf offspring ?
(b) What is the genotype of tall plants which always produced tall offspring ?
(c) What is the genotype of
Define variation in relation to a species. Why is variation beneficial to the species? [Delhi]
Name the first scientist who studied the inheritance of traits from one generation to the next.
A woman has only daughters. Analyse the situation genetically and provide a suitable explanation.
In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better body design’ why or why not ?
What do you understand by the double helical structure of DNA? Who proposed this structure?
How is the equal genetic contribution of male and female parents ensured in the progeny? [Delhi]
What is meant by the term speciation? List four factors which could lead to speciation. [Delhi]
The gene for red hair is recessive to the gene for black hair. What will be the hair colour of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father ?
(a) What will you get in the F1 and F2 generations in the following cross ?
Pure tall pea plant x Pure dwarf pea plant
(b) Is it an example of monohybrid cross or dihybrid cross ?
Give the contrasting traits of the following characters in pea plant and mention which is dominant and which is recessive :
(a) Yellow seed (b) Round seed
(a)What is meant by ‘heredity’ ? What are the units of heredity.
(b) State Mendel’s first law of inheritance.
(a) What are genes ? Where are they located in our body ?(a) What are genes ? Where are they located in our body ?
(b) What is meant by dominant genes and recessive genes ? Give one example of each.
(c) Explain how, characteristics (or traits) are inherited through genes.
The forelimbs of a frog, a bird and a man show the same basic design (or basic structure) of bones. What name is given to such organs ?
Out of the wing of a bird, wing of an insect and the wing of a bat :
(a) which two are homologous organs ?
(b) which two are analogous organs ?
Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?
Out of bacteria, spider, fish and chimpanzee, which organism has a better body design in evolutionary terms ? Give reason for your answer.
(a) Define ‘speciation’. Explain how speciation occurs.
(b) Will geographical isolation be a major factor in the speciation of a self-pollinating plant species ? Give reason for your answer.
Do genetic combination of mothers play a significant role in determining the sex of new born?
A man with blood group A marries a woman with blood O and their daughter has blood group O. Is this information enough to tell you which of the traits blood group A or O is dominant ? Why or why not ?
Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?
Give an example of characteristics being used to determine how close two species am in evolutionary terms ?
A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?