NCERT Solutions Class 10th Science Chapter - 8 Heredity Question & Answer

Textbook	NCERT
Class	10^th
Subject	Science
Chapter	8^th
Chapter Name	Heredity
Category	Class 10th Science
Medium	English
Source	Last Doubt

NCERT Solutions Class 10th Science Chapter – 8 Heredity Question & Answer In This Chapter We will read about Heredity, What is heredity and its types?, Who defined heredity?, Which is bigger DNA or gene?, Why DNA is called unit of heredity?, Is called heredity?, What are the two types of heredity?, Who is called father of heredity? etc.

1. If a 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?

Answer – Trait B is more probable to arise early as this trait has already been existing and replicating in a larger percentage of the population as compared to trait A

2. How does the creation of variations in a species promote survival?

Answer – Genetic variations enable the species to better adapt to changes in its environment. Moreover, it is an important force in evolution as it allows the frequency of alleles to increase or decrease through natural selection. These variations will determine the difference between extinction or continuation of the species.

1. How do Mendel’s experiments show that traits may be dominant or recessive?

Answer – Mendel showed that the traits can either be dominant or recessive through his experiments that focused on mono-hybrid cross. The experiment involved him crossing tall (TT) pea plants with dwarf (tt) pea plants. The resultant plants which formed after fertilization represented the F1 (or filial) generation. All the F1 plants were tall. Mendel then proceeded to self-pollinate the filial generation plants and the result was that 1/4th of the plants obtained in the F2 generation were dwarfs. From this experiment, Mendel concluded that the F1 tall plants were not true-breeding, instead they carried the traits for both tall and dwarf heights. A portion of the plants were tall due to the fact that the traits for tallness were dominant over the traits for dwarfness. This cements the notion that traits can either be dominant or recessive.

2. How do Mendel’s experiments show that traits are inherited independently?

Answer – During dihybrid cross by Mendel, it was observed that when two pairs of traits were considered; each trait expressed independently of the other. Thus, Mendel was able to propose the Law of Independent Assortment which says about the independent inheritance of traits.

3. A man with blood group A marries a woman with blood group 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?

Answer – Given information is not enough to tell us which characteristics are dominant –blood group A or O. Blood type A is always dominant in ABO blood and blood type O is always recessive. Here, the father’s blood group may be genotypically AA (homozygous) or AO (heterozygous), whereas that of mother can be OA or OO.

4. How is the sex of the child determined in human beings?

Answer – Sex of child in humans is determined by the males. Males have XY chromosomes while females have XX chromosomes. Hence, if –

• The male’s X chromosomes combines with the female’s X chromosomes, the mother gives birth to a girl.
• The male’s Y chromosome combines with the female’s X chromosome, the mother gives birth to a boy.

NCERT Solutions Class 10th Science Chapter - 7 Control and Coordination Question & Answer

NCERT Solutions Class 10th Science Chapter - 7 Control and Coordination Question & Answer

1) Female gametes
2) Male gametes

1. A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as

(a) TTWW
(b) TTww
(c) TtWW
(d) TtWw

Answer – (c) TtWW

2. A study found that children with light-colored eyes are likely to have parents with light-colored eyes. On this basis, can we say anything about whether the light eye color trait is dominant or recessive? Why or why not?

Answer – Knowledge of at least 3 generations is required for finding if an attribute is dominant or recessive. Hence, it is not possible to identify if the given trait is dominant or recessive.

3. Outline a project which aims to find the dominant coat color in dogs.

Answer – Dogs have a certain set of genes that govern coat color. There are a minimum of eleven known sequence series (A, B, C, D, E, F, G, M, P, S, T) that influence the colour of a dog. A dog inherits one copy from each of its parents. As an example, within the B series, a dog is genetically black or brown. Assume that one parent is homozygous black (BB), whereas the other parent is homozygous brown (bb).
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In this case, all the offspring’s are going to be heterozygous (Bb).Since black (B) is dominant, all the offspring’s are going to be black. However, they are going to have each B and b alleles. If such heterozygous pups are crossed, they are going to produce 25 homozygous blacks (BB), 15 heterozygous black (Bb), and 25 homozygous brown (bb) offspring’s.
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4. How are the areas of study – evolution and classification – interlinked?

Answer – Classification and evolution are two related fields of biology. Evolution pertains to how organisms evolve and classification deals with finding out how two species are related to each other. For example, evolution and fossil evidence point to the fact that Australopithecus afarensis is considered one of our earliest ancestors. And classification tells us that Australopithecus afarensis belongs to the genus Homo, which is also the same genus as modern humans.

NCERT Solution Class 10th Science All Chapters Question & Answer

Chapter 1 – Chemical Reactions and Equations

Chapter 2 – Acids, Bases, and Salts

Chapter 3 – Metals and Non-Metals

Chapter 4 – Carbon and Its Compounds

Chapter 5 – Life Processes

Chapter 6 – Control and Coordination

Chapter 7 – How Do Organisms Reproduce

Chapter 8 – Heredity and Evolution

Chapter 9 – Light reflection and refraction

Chapter 10 – Human eye and colorful world

Chapter 11 – Electricity