10th Science Unit 19 Book Back Answer

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Samacheer Kalvi 10th Science Unit 19 Book Back Questions with Answers:

Samacheer Kalvi 10th Std  Science Book Back 1 Mark and 2 Mark Questions with Answers PDF in Science uploaded and available below. 10th Standard New Science Syllabus 2022 – Biology 19 Origin And Evolution Of Life Science Book Back Answers available for both English and Tamil mediums. Tamil Nadu Samacheer Kalvi 10th Science Book Portion consists of  23 Units. Science Book Contain Physics 01- 06, Chemistry 07 – 11, Biology 12 – 22 and Visual Communications  23 units. Check Unit-wise and Full Class 10th Science Book Back Answers/ Guide 2022 PDF format for Free Download for both English and Tamil Medium. Samacheer Kalvi 10th Science Book back Solutions/Answers below:

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Samacheer Kalvi 10th Science Book Subject One Mark, Two Mark Guide questions and answers are available below. Check Science Book Back Questions with Answers. Take the printout and use it for exam purposes.

10th Science Book Back Answers

Unit 19 – Origin And Evolution Of Life

I. Choose the best answer:

1. Biogenetic law states that
a) Ontogeny and phylogeny go together
b) Ontogeny recapitulates phylogeny
c) Phylogeny recapitulates ontogeny
d) There is no relationship between phylogeny and ontogeny
Ans : (b) Ontogeny recapitulates phylogeny

2. The ‘use and disuse theory’ was proposed by.
a) Charles Darwin b) Ernst Haeckel
c) Jean Baptiste Lamarck d) Gregor Mendel
Ans : (c) Jean Baptiste Lamarck

3. Palaeontologists deal with
a) Embryological evidence   b) Fossil evidence
c) Vestigial organ evidence  d) All the above
Ans : (b) Fossil evidence

4. The best way of direct dating fossils of recent origin is by
a) Radio–carbon method b) Uranium lead method
c) Potassium–argon method d) Both (a) and (c)
Ans : (a) Radiocarbon method

5. The term Ethnobotany was coined by
a) Khorana   b. J.W. Harsbberger   c) Ronald Ross   d. Hugo de Vries
Ans : (b) J.W. Harsbberger

II. Fill in the blanks:

1. The characters developed by the animals during their lifetime, in response to the environmental changes are called. Ans.: Adaptation
2. The degenerated and non-functional organs found in an organism are called. Ans.: Vestigial
3. The forelimb of bats and humans are examples of organs. Ans.: Homologous
4. The theory of natural selection for evolution was proposed by. Ans.: Charles Darwin




III. True or False (Correct the Statement if it is false)

1. The use and disuse theory of organs’ was postulated by Charles Darwin.
Ans: False. The use and disuse theory of organs’ was postulated by Jean Baptiste Lamarck.

2. The homologous organs look similar and perform similar functions but they have different origin and developmental pattern.
Ans: False. The analogous organs look similar and perform similar functions but they have different origin and developmental pattern.

3. Birds have evolved from reptiles. Ans: True.

IV. Match the following:

Question.

Column A Column B
1. Atavism (a) caudal vertebrae and vermiform appendix
2. Vestigial organs (b) a forelimb of a cat and a bat’s wing
3. Analogous organs (c) rudimentary tail and thick hair on the body
4. Homologous organs (d) a wing of a bat and a wing of an insect
5. Wood park (e) radiocarbon dating
6. W.F. Libby (f) Thiruvakkarai

Answer:

  1. (c) rudimentary tail and thick hair on the body
  2. (a) caudal vertebrae and vermiform appendix
  3. (d) a wing of a bat and a wing of an insect
  4. (b) a forelimb of a cat and a bat’s wing
  5. (f) Thiruvakkarai
  6. (e) radiocarbon dating.

V. Answer in Sentence (1 mark):

1. A human hand, a front leg of a cat, a front flipper of a whale, and a bat’s wing look dissimilar and adapted for different functions. What is the name given to these organs?
Ans: Homologous organs.

2. Which organism is considered to be the fossil bird?
Ans: Archaeopteryx is considered to be a fossil bird.

3. What is the study of fossils called?
Ans: The study of fossils is called Palaeontology.

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