Students can download 10th Science Chapter 19 Origin and Evolution of Life Questions and Answers, Notes, Samacheer Kalvi 10th Science Guide Pdf helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.

Tamilnadu Samacheer Kalvi 10th Science Solutions Chapter 19 Origin and Evolution of Life

Samacheer Kalvi 10th Science Origin and Evolution of Life Text Book Back Questions and Answers

I. Choose the correct answer.

Question 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
Answer:
(b) Ontogeny recapitulates phylogeny

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

Question 3.
Paleontologists deal with:
(a) Embryological evidences
(b) Fossil evidences
(c) Vestigial organ evidences
(d) All the above
Answer:
(a) Embryological evidences

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

Question 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)
Answer:
(a) Radio-carbon method

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

II. Fill in the blanks.

  1. The characters developed by the animals during their life time, in response to the environmental changes are called ………..
  2. The degenerated and non-functional organs found in an organism are called ……….
  3. The forelimb of bat and human are examples of ………. organs.
  4. The theory of natural selection for evolution was proposed by ………..

Answer:

  1. acquired characters
  2. vestigial organs
  3. homologous
  4. Charles Darwin

III. State true or false. Correct the false statements.

  1. The use and disuse theory of organs’ was postulated by Charles Darwin.
  2. The homologous organs look similar and perform similar functions but they have different origin and developmental pattern.
  3. Birds have evolved from reptiles.

Answer:

  1. False – The use and disuse theory of organs’ was postulated by Jean Baptiste Lamarck.
  2. False – The analogous organs look similar and perform similar functions but they have different origin and developmental pattern.
  3. True

IV. Match the following.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life 1
Answer:
A. (iii)
B. (i)
C. (iv)
D. (ii)
E. (vi)
F. (v)

V. Answer in a word or sentence.

Question 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?
Answer:
Homologous organ – as they have inherited from common ancestors with similar developmental pattern in embryos.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

Question 2.
Which organism is considered to be the fossil bird?
Answer:
Archaeopteryx is the fossil bird, found in the Jurassic period.

Question 3.
Why is Archaeopteryx considered to be a connecting link?
Answer:
Archaeopteryx is considered to be a connecting link between reptiles and birds as it had wings with feathers like a bird and had a long tail, clawed digits and conical teeth like a reptile.

VI. Short Answers Questions

Question 1.
The degenerated wing of a kiwi is an acquired character. Why is it an acquired character?
Answer:
The characters developed by the animals during their life time in response to the environmental changes are called acquired character. The acquired characters are transmitted to the offspring by the process of inheritance.

Question 2.
Why is Archaeopteryx considered to be a connecting link?
Answer:
Archaeopteryx is the oldest known fossil bird. It is considered to be a connecting link between reptiles and birds. It had wings with feathers, like a bird. It had a long tail, clawed digits and conical teeth, like a reptile.

Question 3.
Define Ethnobotany and write its importance.
Answer:
Ethnobotany is the study of a region’s plants and their practical uses through the traditional knowledge of the local culture of people.

Question 4.
How can you determine the age of the fossils?
Answer:
The age of fossils is determined by radioactive elements present in it. The elements may be carbon, uranium, lead or potassium. Carbon consumption of animals and plants stops after death, and the decaying process of C14 occurs continuously. The time passed since the death of a plant or animal can be calculated by measuring the amount of C14 present in their body.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

VII. Long Answer Questions

Question 1.
Natural selection is a driving force for evolution-How?
Answer:
Survival of the fittest or Natural selection : During the struggle for existence, the organisms which can overcome the challenging situation, survive and adapt to the surrounding environment. Organisms which are unable to face the challenges, are unfit to survive and disappear. The process of selection of organisms with favourable variation is called as natural selection.

Question 2.
How do you differentiate homologous organs from analogous organs?
Answer:
Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life 2

Question 3.
How does fossilization occur in plants?
Answer:
The process of formation of fossil in the rocks is called Fossilization. The common methods of fossilization include:
1. Petrifaction: Minerals like silica slowly penetrate in and replace the original organic tissue and forms a rock-like fossil. This method of fossilization can preserve hard and soft parts mostly bones and wood fossils are petrified.

2. Mould and cast: A replica of a plant or animal is preserved in sedimentary rocks. When the organism gets buried in sediment it is dissolved by underground water leaving a hollow depression called a mould. It shows the original shape but does not reveal the internal structure. Minerals or sediment fill the hollow depression and form a cast.

3. Preservation: Original remains can be preserved in ice or amber (tree sap). They protect the organisms from decay. The entire plant or animal is preserved.

4. Compression: When an organism dies, the hard parts of their bodies settle at the bottom of the sea bed and are covered by sediment. The process of sedimentation goes on continuously and fossils are formed.

5. Infiltration or Replacement: The precipitation of minerals takes place which later on infiltrates the cell wall. The process is brought about by several mineral elements such as silica, calcium carbonate and magnesium carbonate. Hard parts are dissolved and replaced by these minerals.

VIII. Higher Order Thinking Skills (HOTS).

Question 1.
Arun was playing in the garden. Suddenly he saw a dragon fly sitting on a plant. He observed the wings of it. He thought it looked similar to a wing of a crow. Is he correct? Give reason for your answer.
Answer:
No. Arun is not correct. It is called as Analogous organ. They look similar and perform similar functions, but they have different origin and developmental pattern.

Question 2.
Imprints of fossils tell us about evolution-How?
Answer:
Fossils provide solid evidence that organisms from the past are not the same as those found today. Fossils show a progression of evolution by comparing the anatomical record of fossils with modem and extinct species. Palaeontologist can infer the linkages of their species. For this the body parts such as shell bones or teeth are used. The resulting fossil record tells the story of the part and show the evolution of form over millions of years.

Question 3.
Octopus, cockroach and frog all have eyes. Can we group these animals together to establish a common evolutionary origin. Justify your answer.
Answer:
No, we cannot group these animals together because development of eye is not a point utilised in classification as well as in evolution.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

Samacheer Kalvi 10th Science Origin and Evolution of Life Additional Important Questions and Answers

I. Choose the correct answer.

Question 1.
Life originated in:
(a) Air
(b) Earth
(c) Water
(d) Nitrogen
Answer:
(c) Water

Question 2.
Believers of spontaneous generation theory believed that:
(a) Life originated from a similar organism
(b) Life originated from the air
(c) Life originated only spontaneously
(d) Life originated from pre-existing life
Answer:
(c) Life originated only spontaneously

Question 3.
Which of the following organ in man is not vestigial?
(a) Vermiform appendix
(b) Nictitating membrane
(c) Ear muscles
(d) Epiglottis
Answer:
(a) Vermiform appendix

Question 4.
Analogous organs are:
(a) similar in origin
(b) similar in structure
(c) non-functional
(d) similar in function
Answer:
(b) similar in structure

Question 5.
Wings of locust, pigeon and bat are example of:
(a) Vestigial organs
(b) Analogous organs
(c) Homologous organs
(d) Evolution
Answer:
(a) Vestigial organs

Question 6.
The distance needs to be neither too hot nor too cold is called ______.
(a) habitable zone
(b) Goldilock zone
(c) Aquatic zone
(d) Terrestrial zone.
Answer:
(c) Aquatic zone

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

Question 7.
Fossils are dated by:
(a) Amount of calcium residue
(b) Amount of radio active carbon compound
(c) Association with other mammals
(d) Structure of bones
Answer:
(b) Amount of radio active carbon compound

Question 8.
A basket of vegetables contains carrot, potato and tomato. Which of them represent the correct homologous structures?
(a) Carrot and potato
(b) Carrot and tomato
(c) Radish and carrot
(d) Radish and potato
Answer:
(c) Radish and carrot

Question 9.
Most fossil have been found in:
(a) Black soil
(b) Lava flows
(c) Granite
(d) Sedimentary rocks
Answer:
(d) Sedimentary rocks

Question 10.
Birbal sahni was a:
(a) Zoologist
(b) Lounder of Central Drug Research Institute
(c) Ornithologist
(d) Palaeobotanist
Answer:
(d) Palaeobotanist

Question 11.
Darwin in his ‘Natural Selection Theory’ did not believe in any role of which one of the following in organic evolution.
(a) Parasites and Predators as natural enemies
(b) Survival of the fittest
(c) Struggle for existence
(d) Discontinuous Variation
Answer:
(d) Discontinuous Variation

Question 12.
Fossilizaticn can occur in:
(a) Animals are burned and preserved by natural process
(b) Animals are destroyed by scavangers
(c) Animals are eaten by predators
(d) Animals are destroyed by environmental conditions
Answer:
(a) Animals are burned and preserved by natural process

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

II. Fill in the blanks.

1. Branch of biology which deals with fossils is …………
2. Archaeopteryx is connecting link between reptiles and ………..
3. Darwin explained origin of species through …………
4. The ship on which Darwin worked as naturalist was …………
5. The book Origin of Species was published in the year …………
6. Mutation can be artificially induced by ………..
7. Extraterrestrial states that units of life called ………..
8. The idea of chemical evolution of life was developed by …………..
9. Living being able to reproduce more individuals and form the own progeny is called …………..
10. ……….. is the raw material which plays an important role in evolution.
Answer:
1. Palaeontology
2. Birds
3. Natural selection
4. H.M.S. Beagle
5.1859
6. Radiation
7. Panspermia (spores)
8. Oparin and Haldane
9. Over production
10. Variation

III. Match the following.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life 3
Answer:
A. (ii)
B. (iv)
C. (i)
D. (v)
E. (iii)

IV. State whether True or false. If false write the correct statement.

  1. De Vries is called as the Father of Palaeontology.
  2. NASA is developing the Mars 2020 astrobiology to investigate an astrobiologically details of Mars.
  3. Competition among the individual of same species is Interspecific struggle.
  4. Abiogenesis states that life originates from pre existing life.
  5. The Big Bang theory explains the origin of Universe.

Answer:

  1. False – Leonardo da vinci is called as the Father of Palaeontology.
  2. True
  3. False – Competition among the individual of same species is Intraspecific struggle.
  4. False – Biogenesis states that life originates from pre existing life.
  5. True

V. Answer in a word or sentence.

Question 1.
Who proposed the theory of Natural selection?
Answer:
Charles Darwin

Question 2.
What do you understand by evolution?
Answer:
Formation of new species due to changes in specific characters over several generations as response to natural selection is called evolution.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

Question 3.
How do embryological studies provide evidences for evolution?
Answer:
The embryos from fish to mammals are similar in their early stages of development. The differentiation of their special characters appear in the later stages of development.

Question 4.
Mention three important features of fossils.
Answer:

  1. Fossils are useful in classification of organisms.
  2. Fossils are used in the field of descriptive and comparative analoms.
  3. Fossils throw light on phylogeny and evolution of organisms.

Question 5.
Who is the Father of Indian Paleobotany? What is his contribution in this field.
Answer:
Birbal Sahani is the Father of Indian Paleobotany. He presented his research on two different areas of Paleobotany.

  1. The anatomy and morphology of paleozoic ferns.
  2. The fossil plants of the Indian Gondwana formation.

Question 6.
List out the methods of Fossilization.
Answer:
Common methods of fossilization includes petrifaction molds and cast, carbonization preservation, compression and infiltration.

Question 7.
What are extremophiles?
Answer:
The organisms which live in extreme environmental conditions on earth are called extremophiles.

Question 8.
What is Goldilock zone for life. Name the planet in the Goldilock zone.
Answer:
The Goldilock zone for life is the zone having a right mass to retain an atmosphere and have an orbit at the right distance from its star that allows liquid water to exist and the distance need to be neither too hot or cold. In our solar system – Earth is the only planet in the Goldilock zone.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

Question 9.
What are the three types of struggle for existence?
Answer:

  1. Intra specific struggle
  2. Inter specific struggle
  3. Environmental struggle

Question 10.
What is Atavism?
Answer:
The appearance of the ancestral character in some individuals is called Atavism. Eg: Presence of rudimentary tail in newborn babies.

VI. Short Answer Questions.

Question 1.
Distinguish between acquired and inherited trait with example.
Answer:
Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life 4

Question 2.
What are the aspects of ethnobotany?
Answer:
Ethnobotany has relevance with problems of nutrition, health care and life support system, faith in plants, cottage industries, economic upliftment, conservation of biodiversity and sustainable use of plant resources.

Question 3.
What is the Geological Time Scale?
Answer:
The geological time scale is a system of chronological dating that relates geological rock strata to time and is used by geologists, palaeontologists and other Earth scientists to describe the timing and relationships of events that have occurred during Earth’s history.

Question 4.
Write a note on types of Germinal Variation.
Answer:
Germinal variation are classified into two types:

  1. Continuous variation,
  2. Discontinuous variation

1. Continuous variation : These are small variations which occur among individuals of a population. They are also called as fluctuating variations. They occur by gradual accumulation in a population, e.g. skin colour, height and weight of an individual, colour of eye, etc.

2. Discontinuous variation : These are sudden changes which occur in an organism due to mutations. They do not have any intermediate forms. These large variations are not useful for evolution, e.g. short legged Ancon sheep, six or more digits (fingers) in human, etc.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

Question 5.
Explain the existence for astro biology.
Answer:
The theory explains that any planets can support the existence of life, if it fulfills two important criteria.

  1. It must have a right mass to retain an atmosphere.
  2. It must have an orbit at just the right distance from its star (Sun) that it allows liquid water to exist. Thus, the distance need to be neither too hot or not too cold and is often referred as Goldilock Zone for life.

VII. Long Answer Questions.

Question 1.
Explain the various methods of Fossilization.
Answer:
Common methods of fossilization includes petrifaction, molds and cast, carbonization, preservation, compression and infiltration.
Petrifaction : Minerals like silica slowly penetrate in and replace the original organic tissue and forms a rock like fossil. This method of fossilization can preserve hard and soft parts. Most bones and wood fossils are petrified.

Mold and Cast : A replica of a plant or animal is preserved in sedimentary rocks. When the organism gets buried in sediment it is dissolved by underground water leaving a hollow depression called a mold. It shows the original shape but does not reveal the internal structure. Minerals or sediment fill the hollow depression and forms a cast.

Preservation : Original remains can be preserved in ice or amber (tree sap). They protect the organisms from decay. The entire plant or animal is preserved.

Compression : When an organism dies, the hard parts of their bodies settle at the bottom of the sea bed and are covered by sediment. The process of sedimentation goes on continuously and fossils are formed.

Infiltration or Replacement : The precipitation of minerals takes place which later on infiltrate the cell wall. The process is brought about by several mineral elements such as silica, calcium carbonate and magnesium carbonate. Hard parts are dissolved and replaced by these minerals.

Question 2.
Explain the principles of Lamarckism.
Answer:
Principles of Lamarckism:
(i) Internal vital force : Living organisms or their component parts tend to increase in size continuously. This increase in size is due to the inherent ability of the organisms.

(ii) Environment and new needs : A change in the environment brings about changes in the need of the organisms. In response to the changing environment, the organisms develop certain adaptive characters. The adaptations of the organisms may be in the form of development of new parts of the body.

(iii) Use and disuse theory : Lamarck’s use and disuse theory states that if an organ is used constantly, the organ develops well and gets strengthened. When an organ is not used for a long time, it gradually degenerates.

The ancestors of giraffe were provided with short neck and short – forelimbs. Due to shortage of grass, they were forced to feed on leaves from trees. The continuous stretching of their neck and forelimbs resulted in the development of long neck and long forelimbs which is an example for constant use of an organ. The degenerated wing of Kiwi is an example for organ of disuse.

(iv) Theory of Inheritance of acquired characters : When there is a change in the environment, the animals respond to the change. They develop adaptive structures. The characters developed by the animals during their life time, in response to the environmental changes are called acquired characters. According to Lamarck, the acquired characters are transmitted to the offspring by the process of inheritance.

Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life

VIII. Higher Order Thinking Skills (HOTS).

Question 1.
What is the relationship between mutation and variation?
Answer:
Mutation and variation are the two events involved in the process of evolution. Mutation arises due to errors occurring in DNA during replication or exposure to ultraviolet rays or chemicals. The mutation leads to variation. It brings about changes in a single individual.

Question 2.
Picture of the newborn baby to be given.
Samacheer Kalvi 10th Science Guide Chapter 19 Origin and Evolution of Life 5
(i) Name the phenomenon responsible for the structure marked (a) in the Figure.
Answer:
Atavism

(ii) Give the definition of the phenomenon responsible for the development for the structure marked.
Answer:
The reappearance, ancestral character in some individuals.

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