ICSE , CBSE, NCERT, State Board NEET Exam, Olympiad Question, Study Materials, Biology Important Questions Answers for Heredity and Evolutions class 10 and Class 12 Board exams. Laws relating to Heredity and Evolution. Subjective Questions on Heredity and Evolution

1. ICSE and CBSE Important Questions on Hereditary and
Evolution
Q1. What is Heredity?
Ans. The transmission of characters from one generation to another i.e. from
parents to offsprings is known as heredity.
Q2. What is variation?
Ans. It is the differences between parents and their offsprings or between
offsprings of same parents or between members of the same polpulation.
Q3. What is monohybrid cross?
Ans. Cross involving plants differing in the inheritance of one contrasting feature
only.
Q4. What is dihybrid cross?
Ans. Cross involving plants differing in the inheritance of two contrasting feature.
Q5. What is alleles?
Ans. Alternative form of the same gene is called alleles.
Q6. What is Amniocentesis?
Ans. Amniocentesis is the technique by which heredity disorders due to defects in
genes can be deteced.
Q7. What is human Karyotype?

2. Ans. It is arrangement of human chromosomes in seven groups according to the
types of chromosomes and their sizes.
Q8. What causes variation?
Ans. a) Mutation
b) Recombination
c) Random Mating
Q9. How is human karyotype prepared?
Ans. Human Karyotype is prepared by arranging chromosomes in descending
order during mitotic metaphase stage. Arrangement is done in a way that the
longest pair of chromosomes are drawn first and the sex chromosomes are drawn
the last.
Q10. What causes maternal inheritance?
Ans. Apart from nucleus, mitochondria also posses DNA. When mitochondria
comes into the zygote from the egg, inheritance of mitochondrial DNA occurs
resulting in maternal inheritance.
Q11. Give two examples of Sex-linked inheritance in humans?
Ans. Haemophilia and Red Green colourblindness.
Q12. What is X-linked inheritance?
Ans. When inheritance of recessive sex-linked characters from father to daughter
and then from daughter to her sons takes place, such inheritance is X-linked
inheritance.
Q13. What is haploidiploidy?

3. Ans. Sex Determination in honey bees is called haploidiploidy or arrhenotoky.
Q14. What is heterogametic?
Ans. Sex chromosomes in males produces two types of gametes - X any Y. They
are hererogametic.
Q15. What is homogametic?
Ans. When sex chromosomes are morphologically similar in an individual then the
individual is said to be homogametic. Sex chromosomes in females produces only
one kind of gametes- X chromosome only.
Q16. What is linkage group?
Ans. All the genes present on the same pair of chromosomes and with the tendency
to be inherited together forms a linkage group.
Q17. What is crossing over?
Ans. Crossing over is the physical exchange of the parts of the non-sister
chromatid of the chromosomes of a homologous pair.
Q18. What is Chiasma?
Ans. The point where crossing over occurs is called Chiasma.
Q19. How are somatic cells of an organisms derived?
Ans. The somatic or body cells of an organisms are derived by repeated division of
the zygote that have two identical set of chromosomes i.e., they are deploid.
Q20. When do chromosomes of homologous pair separate out?

4. Ans. Chromosomes of homologous pair separate out during meiosis at the time of
gamate formation.
Q21. What is hybridisation?
Ans. Hybridisation is the process of crossing organisms of different species for
getting desirable qualities in the offsprings.
Q22. What is parent generation?
Ans. Parents generation are the parents used for the first cross. They are
represented as P1.
Q23. What is First Filial Generation?
Ans. The progeny produced from the cross between two pairs of parent generation
is called First Filial Generation.
Q24. What is Second Filial Generation?
Ans. The progeny formed from inbreeding of First Filial generation individuals is
called Second Filial Generation.
Q25. What is monohybrid cross?
Ans. The cross between two parents differing in a single pair of contrasting
characters is called monohybrid cross.
Q26. What is monohybrid ratio?
Ans. The phenotypic ratio of 3 dominants and 1 recessive obtained in Second Filial
generation from the monohybrid crosses is termed as monohybrid ratio. It is shown
as 3:1

5. Q27. What is allelmorphs ?
Ans. Two or more alternative forms of a gene are called alleles.
Q28. What is dihybrid cross?
Ans. The cross in which two parents differing in two pairs of contrasting characters
are considered simultaneously for inheritance pattern is called dihybrid cross.
Q29. What is dihybrid ratio?
Ans The phenotypic ratio obtained in the second Filial generation form a dihybrid
cross is called Menedelian dihybrid cross. It is represented as 9:3:3:1
Q30. What is test cross?
Ans. It is the crossing of the First Filial progeny with the homologous recessive
parent.
Q31. What is reciprocal cross?
Ans. It is the cross in which sex of the parents is reversed. For example, if the cross
father was tall and mother dwarf, then in the reciprocal cross tall parent will be
female and the dwarf parent will be male.
Q32. What is heterozygous?
Ans. An individual with dissimilar alleles for a trait is termed as heterozyzous.
Q33. What is homozygous?
Ans. An individual possessing identical alleles for a trait is termed as homozygous.

6. Q34. What is co-dominance?
Ans. It is the pattern of inheritance where both alleles in the heterozygous
offsprings are fully expressed.
Q35. What is punnett square?
Ans. It is grid used for organising genetic info and making predictions.
Q36. State the law of Dominance?
Ans. When an organism has two different alleles far a trait, the dominant allele is
expressed.
Q37. What is the Law of Segregation?
Ans. The copies of a gene separate during gamate formation in an individual so
that each gamate receive only one copy.
Q38. What is Law of Independent Assortment?
Ans. Alleles of different genes assort independently of one another during gamate
formation.
Q39. Write two contrasting traits with respect to seeds in pea plants that are
studied by Mendel? [ All India ]
Ans. 1. Seed shape round and wrinkled.
2. Seed colour yellow and green.
Q40. Who proposed the the 'Theory of Natural Selection'?
Ans. Charles Darwin in 1859

7. Q41. Write down the location of genes?
Ans. Genes are located as linear segments in the chromosomes.
Q42. Which is the dominant trait in pea plant round yellow or green wrinkled?
[CCE 2015]
Ans. Round Yellow
Q43. What factors results in increase in population of particular traits?
Ans. 1. Variation
2. Genetic Drift
3. Differential reproduction
Q44. What is the chemical constituent of Gene?
Ans. Gene is a segment of deoxyribonucleic acid. It consist of specific sequence of
the nucleotides.
Q45. Why Mendel selected Garden Pes?
Ans. 1. To study a number of contrasting characters for garden pea.
2. Short life span of the pea plant enable to study many generation.
3. Pea plants are self pollinated. When prevented from self pollination, it
undergoes cross pollination.
Q46. What is Genetics?
Ans. It is the branch of science that deals with the Hereditary and variation.

8. Q47. What is variation?
Ans. Difference in characters between the parents and offsprings is called
variation.
Q48. Name the types of variation.
Ans. 1. Somatic Variation
2. Gametic Variation