Chapter 8 The path traversed by life
Short notes
- Panspermia theory.
- Theory of chemical evolution
• Process of chemical evolution – Urey-Miller support
• Evolution of primitive cell
• Theories of evolution
- Theory of Lamarck
- Darwin's theory of Natural selection
- Neo Darwinism – Mutation theory of de Vries
• Evidences of evolution -Fossils, Comparative morphological studies,
Biochemistry and physiology, Molecular biology.
• Human evolution.
The Panspermia theory and the Theory of Chemical evolution.
2. What is the argument of Panspermia theory ?
The Panspermia theory argues that life has originated in some other planet in the universe and accidentally reached the earth.
3. What were the ideas proposed by Oparin and Haldane on the origin of life on the earth?
[Describe the theory of chemical evolution on the origin of life]
The Russian scientist A.I. Oparin (1924) and the British scientist J.B.S Haldane
(1929) are the proponents of the theory of chemical evolution. According to their theory, simple organic molecule are formed first in the primitive ocean by a series of chemical reactions of certain molecules of the primitive atmosphere. By further reactions,complex molecules were formed including genetic material to evolve the first primitive cell, capable of division.
4. Find out three examples for each category shown below.
A. Gases presented in the
primitive atmosphere
* -----------------------
* -----------------------
* -----------------------
B. Simple organic
molecules
* ---------------------
* ---------------------
* ---------------------
C. Complex organic
molecules
* ---------------------
* ---------------------
* ---------------------
D. Most complex
molecules
* -------------------
* -------------------
B. monosaccharides, amino acids, fatty acids
C. polysaccharides, peptides, fats
D. proteins, DNA, RNA
5. The scientists who gave support to the theory of chemical evolution ?
Stanley Miller and Harold Urey.
6. Which were the conditions of the primitive earth, recreated by Stanley Miller and Harold Urey ?
Stanley Miller and Harold Urey re-created the experimental set up, in which the glass flask considered as the primitive atmosphere that contained methane, ammonia, hydrogen and water vapour. Instead of lightning or other energy sources, they passed high voltage electricity through the gaseous mixture. The condensed water from this gaseous mixture was considered as the primitive ocean.
7. Oparin : Haldane,
Stanley Miller : --------- ?
Harold Urey.
8. The organic substances synthesized through Urey-Miller experiment ?
Amino acids.
9. According to Oparin and Haldane hypotheses, life evolved in------------- as a result of chemical reactions of inorganic molecules, for millions of years, after the origin of earth.
Oceans
10. The evolutionary stages after the origin of earth.
Origin of earth→ Chemical evolution→ First form of life→ Prokaryotes→
Eukaryotes→ Multicellular organisms.
11. Organisms without definite nucleus : Prokaryotes,
Organism with nucleus and membraneous bound cell organelles : ------------ ?
Eukaryotes.
12. The important theories related to organic evolution. Name the proponent of each theory.
* Theory of inheritance of acquired characters by Jean Baptist Lamarck.
* Theory of natural selection by Charles Robert Darwin.
* Theory of mutation by Hugo deVries.
13. The first person who tried to explain organic evolution but did not get acceptance by the scientific world ?
J.B. Lamarck.
14. Explain the ideas of J.B. Lamarck about organic evolution.
Theory of Inheritance of Acquired characters.
Continuous use or disuse of an organ results variations to develop changes in the structure of that organ (Acquired characters). These will be transmitted to the next generation to form new species.
15. Why did scientists criticize Lamarck's view ?
The changes in the body (Acquired characters) that occur in the life time of an organism do not affect its genetic constitution and hence not possible to transmit to the next generation.
16. 'Giraffes with short necks when faced scarcity of food eventually developed in to those with long necks'.
How can you described the above view of Lamarck in the light of the view of Darwin ?
When faced scarcity of food, only giraffes with favourable neck (long neck to reach out to tall trees) could survive and others get eliminated.
17. Describe the theory of Natural Selection proposed by Charles Darwin.
Variations develops in each species. Only those variations, which are favourable to that nature, survive and those which are unfavourable get eliminated. According to Darwin, organisms of one kind, when produced in large numbers (Over Production), compete for food, space, mate, and other limited resources (Struggle for Existence). In this struggle, only organisms with favourable variations survive in that nature (Survival of the Fittest). Over a long period,the favourable variations accumulate, resulting the formation of new species.
18. Acquired variations : Lamarck,
Favourable variations : --------------- ?
Darwin.
19. What were the things that influenced Charles Darwin to thought about the importance of nature in the survival or elimination of organisms ?
His studies in Galapagos Islands and the population theory of Robert Malthus.
20. How Darwin could understand that the 13 different finches found in Galapogos
Islands came from a common ancestor ?
Though the finches were similar in sound and nesting habits, only they showed differences in food and food habits. [Insectivore finches have small beaks, cactus feeding finches have long and sharp beaks, woodpecker finches feed on worms in tree trunks have sharp beaks and ground finches feed on seeds have large beaks etc.] So, Darwin thought that they were evolved from a common ancestor.
21. According to Darwin, what might be the reasons for the peculiarities of the beaks of finches ?
The finches of Darwin's had beaks adapted to their feeding habits. When scarcity of food occurred in each island,only beaks with favourable variations (or adaptations) to that nature might have survived there.
22. Book published by Charles Darwin with his theory, Natural Selection ?
Origin Of Species by means of Natural Selection.
23. The ship by which Charles Darwin reached Galapogos Islands ?
HMS Beagle.
24. The theory of Robert Malthus was also influenced Charles Darwin to thought about the importance of nature in the survival or elimination of organisms. What was Malthu's theory ?
In his theory of population, Robert Malthus pointed out that rate of food production is not
proportionate to the growth rate of human population, and when scarcity of food occur, it
will lead to diseases, starvation and struggle for existence.
25. What, according to Darwin, is the cause of the struggle for existence ?
According to Darwin, organisms of one kind, when produced in large numbers (Over Production), compete for food, space, mate, and other limited resources (Struggle for Existence).
26. What was the limitation in Darwin's theory ? Who gave sufficient explanations to this ?
Darwin could not explain the reasons for continuous variations in organisms. However, Hugo deVries explained that one of the reasons for variations in organisms is mutation (sudden changes that occur in genes).
27. What do you mean by Neo Darwinism ?
Neo Darwinism is the modified version of Darwin's theory in the light of new information from the branches of genetics, cytology, geology and paleontology about the reasons of variations occurred in organisms. Hugo deVries first supported Darwin by his theory of mutation.
28. Charles Darwin : Theory of natural selection
Hugo deVries : ------------- ?
Mutation theory.
29.In what ways Hugo de Vries described evolution ?
Hugo de Vries described that sudden and heritable changes (mutation) lead to evolution.
30. The branches of science which provide evidences to organic evolution.
- Palaeontology (fossil study),
- Comparative morphological studies,
- Biochemistry-physiology
- Molecular biology.
31.Define fossils.
Fossils are remnants of primitive organisms , preserved in earth crust.
32. What evidences of organic evolution do the study of fossils (Palaeontology) reveal ?
The study of fossils reveals that complex structured organisms are evolved from primitive simple organisms.
Certain linking fossils reveal the evolution of one form of organisms from another form.
Extinction of some species as well as the emergence of new species .
33. 'Comparative study of structure gives evidences to evolution'. Evaluate this statement.
Though there are differences in the external structure (morphology) among different organisms , there are certain similarities in their internal structure (anatomy). The evidences from the comparative morphological studies justify the inferences that all organisms were evolved from a common ancestor.
For example,
The forelimbs in lizard, bat and sea cow are internally similar but morphologically different (homologous organs). Reason for these differences are their adaptations to live their own habitats.
34. What do you mean by homologous organs?
Organs that are similar in structure but perform different functions are called homologous organs.
35. How do biochemistry and physiology justify evolution ?
All organisms are made up of cells with protoplasm. There are similarities among the cell organelles and cellular activities. Enzymes control chemical reactions and energy is stored in ATP molecules in all organisms. Hereditary factors are gene , seen in DNA and the structure of DNA is alike in all.
Carbohydrates, proteins and fats are the basic substances. There are similarities in growth,
excretion etc.
36. What evolutionary interference can be arrived from the evidences from the comparative morphological , Biochemical and physiological studies ?
All organisms were evolved from a common ancestor.
37. What evidences of organic evolution do the study of molecular biology provide us?
a). Through a comparative study of protein molecules in different species, the evolutionary relationship (similarity / difference) among organisms can be identified.
For instance, we can analyse the similarities or differences in the sequence of amino acids in the beta chain of haemoglobin molecules of different mammals and there by we can understand about the evolutionary relationship among them.
b). Mutations are the main reason for evolutionary changes. Through the molecular studies, we can find out how mutation occur in the genes that determine amino acid sequence in protein molecules. From this we can infer the period of separation of different group of organisms from their ancestor.
40. Find out the missing links in the following evolutionary series of hominoidea.
Gibbon→ ------A------ →Gorilla →--------B------→ Man.
A- Orangutan B- Chimpanzee.
41. Do you agree with the statement that man is evolved from monkeys ? What is your opinion ?
This statement is wrong. Man come under the group Hominoidea while monkeys are included in Cercopithecoidea. It is believed that both the ancestors of man and monkeys are evolved from a common ancestor.
42. The oldest fossil of the genus ,Homo ?
Homo habilis
43. How do modern man differ from the other groups of human beings ?
Modern man have developed brain and equipped with advanced technologies.
44. Table showing the organisms that are included in the evolutionary history of modern man.
45. Do the interventions of modern man cause any change to natural evolutionary process ? How ?
Yes. Biodiversity is on a dangerous decline due to the interference of human beings in nature and natural resources. By human interventions climatic changes brought in as well as the extinction of many organisms.
46. Here is an incomplete illustration of human evolutionary tree. Find out the missing links.
A- Australopithecus
B- Homo habilis
C- Homo neanderthalensis.
Prepared by Rasheed Odakkal, GVHSS Kondotty -9846626323
Contents
• Origin of first life form on earth- Panspermia theory.
- Theory of chemical evolution
• Process of chemical evolution – Urey-Miller support
• Evolution of primitive cell
• Theories of evolution
- Theory of Lamarck
- Darwin's theory of Natural selection
- Neo Darwinism – Mutation theory of de Vries
• Evidences of evolution -Fossils, Comparative morphological studies,
Biochemistry and physiology, Molecular biology.
• Human evolution.
Questions and answers
1. The theories that are related to the origin of life in earth ?The Panspermia theory and the Theory of Chemical evolution.
2. What is the argument of Panspermia theory ?
The Panspermia theory argues that life has originated in some other planet in the universe and accidentally reached the earth.
3. What were the ideas proposed by Oparin and Haldane on the origin of life on the earth?
[Describe the theory of chemical evolution on the origin of life]
The Russian scientist A.I. Oparin (1924) and the British scientist J.B.S Haldane
(1929) are the proponents of the theory of chemical evolution. According to their theory, simple organic molecule are formed first in the primitive ocean by a series of chemical reactions of certain molecules of the primitive atmosphere. By further reactions,complex molecules were formed including genetic material to evolve the first primitive cell, capable of division.
4. Find out three examples for each category shown below.
A. Gases presented in the
primitive atmosphere
* -----------------------
* -----------------------
* -----------------------
B. Simple organic
molecules
* ---------------------
* ---------------------
* ---------------------
C. Complex organic
molecules
* ---------------------
* ---------------------
* ---------------------
D. Most complex
molecules
* -------------------
* -------------------
* -------------------
A. methane, ammonia, hydrogenB. monosaccharides, amino acids, fatty acids
C. polysaccharides, peptides, fats
D. proteins, DNA, RNA
5. The scientists who gave support to the theory of chemical evolution ?
Stanley Miller and Harold Urey.
6. Which were the conditions of the primitive earth, recreated by Stanley Miller and Harold Urey ?
Stanley Miller and Harold Urey re-created the experimental set up, in which the glass flask considered as the primitive atmosphere that contained methane, ammonia, hydrogen and water vapour. Instead of lightning or other energy sources, they passed high voltage electricity through the gaseous mixture. The condensed water from this gaseous mixture was considered as the primitive ocean.
7. Oparin : Haldane,
Stanley Miller : --------- ?
Harold Urey.
8. The organic substances synthesized through Urey-Miller experiment ?
Amino acids.
9. According to Oparin and Haldane hypotheses, life evolved in------------- as a result of chemical reactions of inorganic molecules, for millions of years, after the origin of earth.
Oceans
10. The evolutionary stages after the origin of earth.
Origin of earth→ Chemical evolution→ First form of life→ Prokaryotes→
Eukaryotes→ Multicellular organisms.
11. Organisms without definite nucleus : Prokaryotes,
Organism with nucleus and membraneous bound cell organelles : ------------ ?
Eukaryotes.
12. The important theories related to organic evolution. Name the proponent of each theory.
* Theory of inheritance of acquired characters by Jean Baptist Lamarck.
* Theory of natural selection by Charles Robert Darwin.
* Theory of mutation by Hugo deVries.
13. The first person who tried to explain organic evolution but did not get acceptance by the scientific world ?
J.B. Lamarck.
14. Explain the ideas of J.B. Lamarck about organic evolution.
Theory of Inheritance of Acquired characters.
Continuous use or disuse of an organ results variations to develop changes in the structure of that organ (Acquired characters). These will be transmitted to the next generation to form new species.
15. Why did scientists criticize Lamarck's view ?
The changes in the body (Acquired characters) that occur in the life time of an organism do not affect its genetic constitution and hence not possible to transmit to the next generation.
16. 'Giraffes with short necks when faced scarcity of food eventually developed in to those with long necks'.
How can you described the above view of Lamarck in the light of the view of Darwin ?
When faced scarcity of food, only giraffes with favourable neck (long neck to reach out to tall trees) could survive and others get eliminated.
17. Describe the theory of Natural Selection proposed by Charles Darwin.
Variations develops in each species. Only those variations, which are favourable to that nature, survive and those which are unfavourable get eliminated. According to Darwin, organisms of one kind, when produced in large numbers (Over Production), compete for food, space, mate, and other limited resources (Struggle for Existence). In this struggle, only organisms with favourable variations survive in that nature (Survival of the Fittest). Over a long period,the favourable variations accumulate, resulting the formation of new species.
Favourable variations : --------------- ?
Darwin.
19. What were the things that influenced Charles Darwin to thought about the importance of nature in the survival or elimination of organisms ?
His studies in Galapagos Islands and the population theory of Robert Malthus.
20. How Darwin could understand that the 13 different finches found in Galapogos
Islands came from a common ancestor ?
Though the finches were similar in sound and nesting habits, only they showed differences in food and food habits. [Insectivore finches have small beaks, cactus feeding finches have long and sharp beaks, woodpecker finches feed on worms in tree trunks have sharp beaks and ground finches feed on seeds have large beaks etc.] So, Darwin thought that they were evolved from a common ancestor.
21. According to Darwin, what might be the reasons for the peculiarities of the beaks of finches ?
The finches of Darwin's had beaks adapted to their feeding habits. When scarcity of food occurred in each island,only beaks with favourable variations (or adaptations) to that nature might have survived there.
22. Book published by Charles Darwin with his theory, Natural Selection ?
Origin Of Species by means of Natural Selection.
23. The ship by which Charles Darwin reached Galapogos Islands ?
HMS Beagle.
24. The theory of Robert Malthus was also influenced Charles Darwin to thought about the importance of nature in the survival or elimination of organisms. What was Malthu's theory ?
In his theory of population, Robert Malthus pointed out that rate of food production is not
proportionate to the growth rate of human population, and when scarcity of food occur, it
will lead to diseases, starvation and struggle for existence.
25. What, according to Darwin, is the cause of the struggle for existence ?
According to Darwin, organisms of one kind, when produced in large numbers (Over Production), compete for food, space, mate, and other limited resources (Struggle for Existence).
26. What was the limitation in Darwin's theory ? Who gave sufficient explanations to this ?
Darwin could not explain the reasons for continuous variations in organisms. However, Hugo deVries explained that one of the reasons for variations in organisms is mutation (sudden changes that occur in genes).
27. What do you mean by Neo Darwinism ?
Neo Darwinism is the modified version of Darwin's theory in the light of new information from the branches of genetics, cytology, geology and paleontology about the reasons of variations occurred in organisms. Hugo deVries first supported Darwin by his theory of mutation.
28. Charles Darwin : Theory of natural selection
Hugo deVries : ------------- ?
Mutation theory.
29.In what ways Hugo de Vries described evolution ?
Hugo de Vries described that sudden and heritable changes (mutation) lead to evolution.
30. The branches of science which provide evidences to organic evolution.
- Palaeontology (fossil study),
- Comparative morphological studies,
- Biochemistry-physiology
- Molecular biology.
31.Define fossils.
Fossils are remnants of primitive organisms , preserved in earth crust.
32. What evidences of organic evolution do the study of fossils (Palaeontology) reveal ?
The study of fossils reveals that complex structured organisms are evolved from primitive simple organisms.
Certain linking fossils reveal the evolution of one form of organisms from another form.
Extinction of some species as well as the emergence of new species .
33. 'Comparative study of structure gives evidences to evolution'. Evaluate this statement.
Though there are differences in the external structure (morphology) among different organisms , there are certain similarities in their internal structure (anatomy). The evidences from the comparative morphological studies justify the inferences that all organisms were evolved from a common ancestor.
For example,
The forelimbs in lizard, bat and sea cow are internally similar but morphologically different (homologous organs). Reason for these differences are their adaptations to live their own habitats.
34. What do you mean by homologous organs?
Organs that are similar in structure but perform different functions are called homologous organs.
35. How do biochemistry and physiology justify evolution ?
All organisms are made up of cells with protoplasm. There are similarities among the cell organelles and cellular activities. Enzymes control chemical reactions and energy is stored in ATP molecules in all organisms. Hereditary factors are gene , seen in DNA and the structure of DNA is alike in all.
Carbohydrates, proteins and fats are the basic substances. There are similarities in growth,
excretion etc.
36. What evolutionary interference can be arrived from the evidences from the comparative morphological , Biochemical and physiological studies ?
All organisms were evolved from a common ancestor.
37. What evidences of organic evolution do the study of molecular biology provide us?
a). Through a comparative study of protein molecules in different species, the evolutionary relationship (similarity / difference) among organisms can be identified.
For instance, we can analyse the similarities or differences in the sequence of amino acids in the beta chain of haemoglobin molecules of different mammals and there by we can understand about the evolutionary relationship among them.
b). Mutations are the main reason for evolutionary changes. Through the molecular studies, we can find out how mutation occur in the genes that determine amino acid sequence in protein molecules. From this we can infer the period of separation of different group of organisms from their ancestor.
38. The differences of the sequential arrangement of amino acids in the beta chain of haemoglobin of man with other animals are given below. Which one is so close to human being?
Chimpanzee No difference
Gorilla Difference of 1 amino acid
Rat Difference of 31 amino acids
Chimpanzee is so close to human being .
39. Evolutionary tree of certain organisms related to man.
Gibbon→ ------A------ →Gorilla →--------B------→ Man.
A- Orangutan B- Chimpanzee.
41. Do you agree with the statement that man is evolved from monkeys ? What is your opinion ?
This statement is wrong. Man come under the group Hominoidea while monkeys are included in Cercopithecoidea. It is believed that both the ancestors of man and monkeys are evolved from a common ancestor.
42. The oldest fossil of the genus ,Homo ?
Homo habilis
43. How do modern man differ from the other groups of human beings ?
Modern man have developed brain and equipped with advanced technologies.
44. Table showing the organisms that are included in the evolutionary history of modern man.
Yes. Biodiversity is on a dangerous decline due to the interference of human beings in nature and natural resources. By human interventions climatic changes brought in as well as the extinction of many organisms.
46. Here is an incomplete illustration of human evolutionary tree. Find out the missing links.
A- Australopithecus
B- Homo habilis
C- Homo neanderthalensis.
Prepared by Rasheed Odakkal, GVHSS Kondotty -9846626323
Class X Geography eng
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UNIT 3 Lore of values
The Best Investment I Ever Made
The Ballad of Father Gilligan
The danger of a single story
UNIT 2 The frames
Notes
Discourses
Project Tiger textual questions and answers
My Sister's Shoes textual questions and answers
Blowin' in the wind textual questions and answers
Project Tiger
My sister's shoes
Blowin in the wind
Chapter 1 തരംഗചലനം
à´…à´¨ുà´¦ൈà´°്à´˜്à´¯ തരംà´—ം
തരംà´— സവിà´¶േഷതകള്
à´…à´¨ുരണനം
à´ª്à´°à´¤ിà´§്വനി
Chapter 2 à´µൈà´¦ൃുതപ്à´°à´µാഹത്à´¤ിà´¨്à´±െ ഫലങ്ങള്
à´«ിലമെà´¨്à´±് à´²ാà´®്à´ª് (ഇന്à´•ാà´¨്à´¡à´¸െà´¨്à´±് à´²ാà´®്à´ª് )
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LED à´²ാà´®്à´ª്
ആര്à´•്à´•് à´²ാà´®്à´ª്
Chapter 1 Know The Plant World Closely / സസ്യലോà´•à´¤്à´¤െ à´…à´Ÿുà´¤്തറിà´¯ാം
Photosynthesis
Stomata
Photosynthesis
Realise chloroplast and Chlorophyll
Photosynthesis and respiration
Vanda
Loranthus
Rafflesia
Neottia
Monotropa
Climbers and creepers
Climbers , motion video
Mangroves
Roots
Unit 1 The Mirror
The Mirror
The Magic Mirror
Use of a and an
Chapter 3 OUR FAMILY / നമ്à´®ുà´Ÿെ à´•ുà´Ÿുംà´¬ം
Family is the basic unit of society
Nuclear family
Extended family
Joint family
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