i need 20 important questions from the chapter heredity and evolution.
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1. What are acquired characteristics? (Imp.)
Ans. Characteristics which people acquire during their lives, like knowledge and skills are called acquired
characteristics. Development of muscles in an athlete is an acquired characteristic.
2. What is variation?
Ans. Variation is the difference or dissimilarity between parents and children as individuals of a species. It can
be defined as the occurrence of difference among the individuals of a species.
3. Why is variation less common in asexually reproducing organisms?
Ans. Asexual reproduction tends to preserve the similarities among all the individuals belonging to a given line
of descent. Therefore, asexually reproducing organisms show more hereditary features.
4. Clarify the term heredity and variation. (Imp.)
Ans. Heredity means continuity of features from one generation to another whereas variation is the
occurrence of differences among the individuals.
5. Define variation in relation to a species. Why is variation beneficial to the species? (Imp.)
Ans. The differences or dissimilarities between the parents and the children as individuals of the same species
are called variations.
Variation is beneficial to the species as
(i) they enable the organisms to adapt themselves in the changing environment.
(ii) variations form the basis of heredity.
(iii) they form raw materials for evolution and development of new species.
6. What are autosomes?
Ans. In females two copies of an unpaired chromosome are present along with paired chromosomes. These
are known as sex chromosomes. The rest of the chromosomes are known as autosomes.
7. What is the reason that a male is called heterogametic?
Ans. A male is called heterogametic because he forms two different types of gametes. One containing X
chromosome and the other containing Y chromosome.
8. What was the basic study material of Mendel? How did he bring in the term “factor”?
Ans. The basic study material of Mendel were the contrasting characters in various generations of garden pea.
He said that these characters are controlled by units known as factors.
9. How many chromosomes are there in the human
(a) Ovum (b) Liver cell
Ans. (a) Ovum 23 chromosomes; (b) Liver cell 46 chromosomes.
10. How did the Mendelian factors acquire a change in the terminology? Who changed it?
Ans. The carriers of hereditary information were called factors by Mendel. Johanssen later called these factors
genes.
11. Why can the wings of a bird and the wings of a bat not be considered analogous? (Imp.) Ans. Wings of a
bird and a bat are modified forelimbs and hence, show structural similarity.
Hence, they cannot be considered as analogous structures.
Ans. Characteristics which people acquire during their lives, like knowledge and skills are called acquired
characteristics. Development of muscles in an athlete is an acquired characteristic.
2. What is variation?
Ans. Variation is the difference or dissimilarity between parents and children as individuals of a species. It can
be defined as the occurrence of difference among the individuals of a species.
3. Why is variation less common in asexually reproducing organisms?
Ans. Asexual reproduction tends to preserve the similarities among all the individuals belonging to a given line
of descent. Therefore, asexually reproducing organisms show more hereditary features.
4. Clarify the term heredity and variation. (Imp.)
Ans. Heredity means continuity of features from one generation to another whereas variation is the
occurrence of differences among the individuals.
5. Define variation in relation to a species. Why is variation beneficial to the species? (Imp.)
Ans. The differences or dissimilarities between the parents and the children as individuals of the same species
are called variations.
Variation is beneficial to the species as
(i) they enable the organisms to adapt themselves in the changing environment.
(ii) variations form the basis of heredity.
(iii) they form raw materials for evolution and development of new species.
6. What are autosomes?
Ans. In females two copies of an unpaired chromosome are present along with paired chromosomes. These
are known as sex chromosomes. The rest of the chromosomes are known as autosomes.
7. What is the reason that a male is called heterogametic?
Ans. A male is called heterogametic because he forms two different types of gametes. One containing X
chromosome and the other containing Y chromosome.
8. What was the basic study material of Mendel? How did he bring in the term “factor”?
Ans. The basic study material of Mendel were the contrasting characters in various generations of garden pea.
He said that these characters are controlled by units known as factors.
9. How many chromosomes are there in the human
(a) Ovum (b) Liver cell
Ans. (a) Ovum 23 chromosomes; (b) Liver cell 46 chromosomes.
10. How did the Mendelian factors acquire a change in the terminology? Who changed it?
Ans. The carriers of hereditary information were called factors by Mendel. Johanssen later called these factors
genes.
11. Why can the wings of a bird and the wings of a bat not be considered analogous? (Imp.) Ans. Wings of a
bird and a bat are modified forelimbs and hence, show structural similarity.
Hence, they cannot be considered as analogous structures.
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