NIOS Class 12 Biology Chapter 1 Solution – Origin and Evolution of Life and Introduction to Classification

NIOS Class 12 Biology Chapter 1 Solution – Origin and Evolution of Life and Introduction to Classification

NIOS Class 12 Biology Solution Chapter 1 Origin and Evolution of Life and Introduction to Classification . NIOS Class 12 Biology Chapter 1 Question Answers Download PDF. NIOS Class 12 Biology Notes.

NIOS Class 12 Biology Chapter 1 Solution

Board	NIOS
Class	12th (Higher Secondary)
Subject	Biology
Topic	Question Answer, Solution, Notes

INTEXT 1.1

1.)  Approximately how many years ago was the earth formed?

Ans: Earth was formed approximately 5 billion years ago.

2.) Who gave the Chemosynthetic Theory for origin of life?

Ans:  A.I. Oparin proposed the theory of chemosynthesis.

3.) Name the four gases present in the primitive atmosphere of the earth.

Ans: The four gases present in the primitive atmosphere of the earth are NH3, CH4, CO2, and water  vapour.

4.) Name one source of energy which was used for chemical combination in primitive atmosphere.

Ans: source of energy which was used for chemical combination in primitive atmosphere is UV rays.

5.) Where did life originate in water or on land?

Ans: The life was originate in water.

6.) What are ‘coacervates’?

Ans: coacervates are aggregates of (life-like) molecules.

7.) In the origin of life, first large molecules were formed from inorganic compounds. Name any two such large molecules.

Ans: Amino acids, fatty acids, sugar are the first large molecules were formed from inorganic

8.) Name the two scientists who experimentally tried to verify Oparin’s hypothesis

Ans:  Miller and Urey are two scientists who experimentally tried to verify Oparin’s hypothesis

INTEXT 1.2

1.) Define organic evolution.

Ans : The term “organic evolution” refers to this slow, gradual development that occurred over the period of geological time with modification from a common ancestor..

2.) Name one fossil animal which forms a connecting link between reptiles and aves.

Ans: Archaeopteryx fossil animal which forms a connecting link between reptiles and aves.

3.) Which organ of man is homologous to the wings of birds?.

Ans : Fore-arm is a organ of man which man is homologous to the wings of birds

 4.) Define vestigial organ.

Ans : Vestigial organ is any small degenerate or imperfectly developed (non-functional) organ or part which may have been complete and functional in some ancestor.

Eg . Appendix in Human body.

5.) Give one example of a connecting link among the living beings.

Ans : Egg laying mammals between reptiles and mammals is a connecting link among the living beings.

6.) Give two examples from molecular biology which support organic evolution

Ans : Cytochrome C , which is vital to the respiratory pathway and ribosomal RNA ,which is protein synthesis are the examples which support organic evolution

INTEXT 1.3

1.) Who gave the theory of natural selection?

Ans : Charles Darwin  gave the theory of natural selection

2.) What is the modern interpretation of Darwin’s theory of evolution called?

Ans :  the modern interpretation of Darwin’s theory of evolution is called Synthetic theory.

 3.) What are the two major contributions of Charles Darwin regarding evolution?

Ans :. The two major contribution  were (i) that all kind of organisms are related through ancestry and (ii) Charles Darwin explained the mechanism of evolution through his theory of natural selection

4.) Give two main features of Neo-Darwinism. (i) (ii).

Ans  :  (i) Variation in population forms the basis of evolution

(ii) Differential reproduction

 5.) What do you mean by “differential reproduction”?.

Ans : A change in the genetic constitution of a population selected by natural selection is responsible for evolution of a new species, since through interaction of variation and Natural Selection more offsprings with favourable genetic changes are born. This is called ‘differential reproduction’

INTEXT1.3

1.)List the sources of organic variation.

Ans : Mutation, Recombination, gene flow, genetic drift are the sources of organic variation

2.) What is ‘industrial melanism’ about? Answer in one or two sentences

Ans : Industrial melanism   the evolution of a variety of peppered moth during industrial revolution, through mutation and Natural Selection.

3.) State one point of difference between (a) allopatric & sympatric speciation (b) Ecological and Ethological Isolation  

Ans :  (a) Due to physical barriers that isolate populations, allopatric speciation results in population differences within a species. Even though sympatric species may coexist in the same region, reproductive barriers divide them.

(b) Both ecological isolation by seasonal or habitual barriers and ethological isolation by barriers of behavioural variations are isolating mechanisms.

4.) What is a panmictic population?

Ans : A population of sexually reproducing organisms in which genes combine at random due to random mating is called panmictic

5.) According to Hardy Weinberg Principle, (p + q)2 = 1. Explain this mathematical expression.

Ans :  (q + q)2 = 1 means frequencies of allelic genes. In a panmictic population if there is no pressure of mutation, selection, genetic drift etc. then the relative frequency i.e., p + q, of any pair of genes remains constant, generation after generation.

INTEXT 1.4

1.) Name the scientists who proposed :

Ans :   (a) Binomial nomenclature-  Carolus Linnaeus

             (b) Five Kingdom Classification –  R.H. Whittaker

2.) Which were the first organisms to appear on earth?

Ans :  Bacteria were the first organisms to appear on earth

3.) Name the taxonomic categories which come before and after family

Ans :  Order and  Genus is the taxonomic categories which come before and after family respectively.

 4.) Name the categories above order level in a correct sequence.

Ans :  Kingdom, phylum, class, order are the categories above order level.

 5.) Rewrite the following in correct form .

Ans :  (a) Mangifera Indica –  Mangifera indica

            (b) Homo Sapiens –  Homo sapiens

            (c) Felis leo – Felis leo

6.) Place the following in their respective kingdoms

 Ans :   (a) Bacteria which curdle the milk. –  Monera

              (b) Cow – Animalae

              (c) Grass- Plantae

              (d) Amoeba- Protoctista

              (e) Bread mould – Fungi

INTEXT 1.5

1.) With reference to viruses fill in the blanks (1, 2 and 3) in the following table

Ans :   

1. Tobacco mosaic virus	Tobacco	Tobacco Mosaic Disease
HIV	2. humans	AIDS
Herpes	human	3.Herpes

 Give one feature because of which viruses are considered non-living.

Ans :    viruses are considered non-living because they cannot reproduce on their own

Name one chemical common to viruses and all other organism

Ans :   Nucleic Acid is the chemical which common to viruses and all other organism

Complete the following :

Ans :  (a) Core particle of virus contains – DNA or RNA

 (b) Coat of virus is made of .Protein

5.) In what way is viroid structurally different from a vrius? 

Ans: A viroid, which is an RNA molecule and  viruses are made up of DNA or RNA molecules that are covered in a protein coat.

6.)   Why are viroids considered a menace for plants that they attack?

Ans :   When viroids  infect plants, they use the enzymes of the host plants to replicate and multiply, which stunts and abnormally grows the plant.