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ASTRONOMY > HISTORY OF EARTH > Flashcards

HISTORY OF EARTH Flashcards

1
Q

What are the HYPOTHESES of the ORIGIN OF THE EARTH

A

Old Planetesimal Hypothesis : George Buffon
New Planetesimal Hypothesis : Geologist, TC Chamberlin and
Astronomer F.R Moulton
Nebular Hypothesis : Immanuel Kant,
Improved by French astronomer:
Laplace
[Kant – Laplace]
Dust Cloud Hypothesis : Karl Von Weizsacker
Tidal Hypothesis : James Jeans and Jeffery

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2
Q

What is the Old Planetesimal Hypothesis?

A

Old Planetesimal Hypothesis : George Buffon

The dynamic encounter theory is the theory for the historical origin of the planets as the result of a near collision of the Sun and Comet. This theory was first proposed on 1749 by Georges Buffon (1707-1788 AD), director of royal botanical collection in Paris. Later Buffon disassociated himself from his own views, giving up his theory of the formation of the planets.

The earth along with other planets and satellites was formed when a comet revolving around the universe stroke the sun millions of years ago.
OR,

According to this hypothesis the Earth along with all other planets and satellites, was formed when a comet revolving around the Universe stroke with Sun many years ago.
OR

Very large amount of matter was thrown out of the sun due to the collision of the sun and another star. Those hot matters cooled and the other planets along with the earth were formed and the remaining mass was the sun.

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3
Q

What is the New Planetesimal Hypothesis?

A

New Planetesimal Hypothesis : 1905 AD
Geologist, TC Chamberlin and Astronomer F.R Moulton
This hypothesis was slightly different from the old planetesimal hypothesis, suggested by Buffon.
It states that 2 stars did not collide but came very close to one another, and due to the gravity of the star, great bulges rose on the sun and the materials remained as large spiral arms and when they cooled, they broke away from the sun and the broken materials combined together to product the planets and the remaining gaseous matter became the sun.

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4
Q

What is the Nebular Hypothesis?

A

Nebular Hypothesis : Immanuel Kant, improved by French astronomer: Laplace
[Kant – Laplace]
The nebular Hypotheses:
-first introduced by German philosopher Kant in 1755 AD and
-Later modified by French Mathematician Laplace in 1976 AD
Since then it is called Kant-Laplace hypothesis.

It is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems).

  • Everything right from the sun, asteroids, planets have all been created by nebula cloud.
  • Stars were formed way before asteroids, planets came into existence.
  • The biggest star is the SUN.
  • Initially there was a nebula cloud which made of helium, hydrogen and other sorts of dust particles,
  • This cloud started rotating very heavily.
  • Because of that most of the heavy particles , hydrogen and helium elements came to the center and started colliding with each other and due to the friction and collision of particles, fusion reaction took place and pure Energy started generating and this created the SUN.
  • If lighter elements went to the center, the heavier moved away from the center like Carbon, Oxygen, Phosphorus, Nitrogen, Iron, Silicon etc. If you see the earth and all the planets, are made of dense elements than STARs.
  • These heavier elements started forming small clumps of clouds, smaller nebular with further rotation, friction and collision of particles. Which lead to formation of a disc shaped cloud and the planets were formed.
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5
Q

What is Dust Cloud Hypothesis?

A

Dust Cloud Hypothesis : Karl Von Weizsacker 1944

Improved version of Kant’s hypothesis.
This hypothesis proposed that the sun and the planets were formed from a large cloud of gases and dust. The light of the star pushed the atoms of the gases and dust to form huge particles which were attracted to each other by pull of gravity.
A huge ball of materials formed the sun and the part of the cloud of dust and gases stayed around the sun and slowly rotated. The huge whirlpools originated in this rotating clouds formed planets.
In this way, the earth was originated in its cold stage.

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6
Q

What is the Tidal Hypothesis?

A

Tidal Hypothesis : James Jeans and Jeffery
Jeans and Jeffery in 1917 AD
Tidal effect occurred on the sun when a big star orbiting round the sun approached it.
A large mass of gas was ejected from the sun due to the tidal effect.
In this course of cooling, the tidal matter fragmented into small pieces forming planets. Satellites etc.
As a result the solar system was formed.
OR,

The British scientists James Jeans and Harold Jeffery in 1917 A.D. explained the origin of the solar system as a result of a close encounter between the Sun and the second star. As a result of detailed mathematical analysis, Jeans concluded that the tidal interaction between the Sun and the passing star caused great attraction and would raise tides on the Sun resulting in the loss of a single cigar-shaped filament of hot gas. Then, the tidal hot matter fragmented from the sun and the fragmented particles cooled down. These particles revolved around the sun. in this way solar system was created.

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7
Q

What are the 2 methods by which the age of the earth is determined?

A

a) By analysis rocks and fossils available on earth

b) By studying the radioactivity of rocks and fossils

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8
Q

‘Origin of earth and human being did not occur at the same time.’ Give any 1 scientific reason.

A

The study of radioactivity of rocks and fossils of human beings present on the earth provides evidence that the origin of the earth and human beings did not occur at the same time.

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9
Q

What is the Smallest and largest section of geological time scale?

A

Smallest : EPOCH

Largest : EON

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10
Q

In how many parts is geological history divided on the basis of existence of living beings?

A

Basis of existence of living beings

a) EON Long period of time e.g billions of years, in geological history, which is divided into ERA’s.
[ Example: Phanerozoic eon, Proterozoic Eon]
b) ERA [Geological Era: duration of time in geological history which is a division of an EON in which important changes or events happened.]
[ Example: Mesozoic Era, Cenozoic Era]
c) PERIOD [Geological Period: length of time which is a division of ERA]
[ Example: Jurassic Period, Cretaceous Period]
d) EPOCH [length of time which is a division of a period in which important changes or events happened]
[ Example: Eocene Epoch, Miocene Epoch]

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11
Q

Why did dinosaurs evolve earlier than human?

A

According to the history of evolution, dinosaurs belong to the class Reptilia and humans belong to class Mammalia.
Dinosaurs are less developed than mammals.
So they evolved earlier.

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12
Q

Living beings evolved after million of years after the formation of earth, why?

A

Earth evolved 4.5 billion years ago. At that time of evolution of earth, it was very hot and there was no suitable environment for the volution and survival of living organisms. So there were no life at the time of the evolution of earth.

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13
Q
  1. How is the estimate age of the earth?
A

4.5 billion years

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14
Q
  1. Write the name of the eras in which green plant and crocodile were evolved on the earth
A

Green Plants – Palaeozoic Era

Crocodiles - Mezozoic Era

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15
Q
  1. Name the eras in which fishes and human being originated on the earth
A

Fish – Palaeozoic Era

Human – Cenozoic Era

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16
Q
  1. What is Cenozoic era
A
  • began about 65 million years ago and continues into the present,
  • is the current documented era in the history of Earth.
  • The current locations of the continents and their modern-day inhabitants, including humans, can be traced to this period.
  • Era of Mammals

-Evolution of -First mammal and horses
-Mammals (like elephant, whale), fish and owl.
-sharp toothed cats and monkeys
-grasses
-ancient human beings and mammoths (giant hairy elephant)
-modern human beings and mammals, dominance of human beings.
Evolution and development of - human beings.

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17
Q
  1. In which eras were frog and horse evolved
A

Frog – Palaeorozic Era

Horse – Cenozoic Era

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18
Q
  1. What is the duration of Mesozoic era?
A

250 million years ago to 650 million years ago

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19
Q
  1. In which era did dinosaur and man evolve
A

Dinosaur – Mesozoic Era

Man – Cenozoic Era

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20
Q
  1. In which era were the dinosaurs evolved and what was the duration of that era
A

Dinosaur – Triassic Period (evolved and extension) Mesozoic Era

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21
Q
  1. What is fossil and fossil fuel?
A

FOSSIL
The relics of plants and animals preserved by rocks which are buried in the rocks of earth’s crust over a long period of time is called fossil.
The literal meaning of fossils is ‘dug up’.

Fossils are found in Sedimentary Rocks.
Study of science which deals with the study of fossils is called “paleontology”.

FOSSIL FUEL
• Fossil Fuels are non-renewable sources of energy.
• Formed from the dead bodies of living beings after millions of years.
• Categories – Coal, Petroleum and Natural Gas used widely in industries, vehicles, kitchen as main source of energy
• Overuse will bring crisis and pollution.
• Found in sedimentary rocks [Not found in igneous rocks, as igneous rocks are formed by volcanic eruption]

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22
Q 
10.	Write the name of eras of existence 
Fern 					: ?
Coniferous Plants			: ?
Evolution of modern Human beings	: ?
Evolution of Primary Mammals		: ?
Dominance of Reptiles			: ?
Evolution of Fish			: ?
Evolution of Frog			: ?
Evolution of dinosaurs 			: ?
Evolution of Owl			: ?
Evolution of Flowering Plant		: ?
A

Fern : Palaeozoic Era
Coniferous Plants : Mesozoic Era
Evolution of modern Human beings : Cenozoic Era
Evolution of Primary Mammals : Cenozoic Era
Dominance of Reptiles : Mesozoic Era
Evolution of Fish : Palaeozoic Era
Evolution of Frog : Palaeozoic Era
Evolution of dinosaurs : Mesozoic Era
Evolution of Owl : Cenozoic Era
Evolution of Flowering Plant : Mesozoic Era

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23
Q
  1. Why is fossil found only in sedimentary rock?
    OR,
    How is information about ancient living beings taken?
A

Found in sedimentary rocks and not found in igneous rocks, as igneous rocks are formed by volcanic eruption.

Sedimentary rocks are formed in much lower pressure and temperature, compared to other rock types. The pressure and temperature are quite low to the extent that they do not destroy the remains of dead plants and animals buried in the rock. These rocks are formed on the Earth surface, under the water,

How is information about ancient living beings taken? [Ans: study of fossils in sedimentary rocks]

24
Q
  1. Write any 2-information obtained by the study of fossil.
    Or,
    The study of fossils in important for human beings. Justify this statement.
    OR,
    Write any 3 information obtained by the study of fossil.
    OR,
    Mention any 3 importance of fossil.
A

Study of fossils:

  • helps us to discover the evolutionary trend of plants and animals on the earth
  • helps us to investigate the deposits of coal and petroleum inside the earths crust.
  • determine the age of rocks, to know geological history and to know about organic evolution on the earth.
25
Q
  1. Why is Mesozoic era called the age of reptiles?
A

In the Mesozoic era there was a dominance of various types of large reptiles like dinosaurs, turtles etc on land and marine water. Hence it was called the age of reptiles.

26
Q
  1. Write any 2 differences between palaeozoic era and Mesozoic era.
A

Palaeozoic -

  • 570 million years ago – 250 million years ago
  • Dinosaurs were not present in this era.
  • Human beings absent

Era of Amphibians
Evolution of Fish and Frog

Mesozoic

  • 250 million years ago – 65 million years ago
  • Dominance of dinosaurs in this era
  • Human beings absent

Era of Reptiles
Era of Creepers

27
Q
  1. Write any 2 difference between Mesozoic era and Cenozoic era.
A

Mesozoic era
250 million years ago – 65 million years ago
Era of Reptiles
Era of Creepers

  • Dominance of dinosaurs in this era
  • Human beings absent

Cenozoic era.
65 million years ago – till date
Era of Mammals

  • Absence of Dinosaurs
  • Dominance of Human Beings
28
Q
  1. Write any 2 differences between coal and mineral oil.
A

COAL

  • Is formed in Solid State
  • generally used in factories as a source of heat

MINERAL OIL

  • is formed in Liquid State
  • generally used to run engine of vehicles.
29
Q

Why are fossils important?

A
  • Provides evidence of living beings
  • Helps to know about the extinct animals and plants.
  • Shows the history of location from where a fossil is obtained.
  • Fossil fuels such as coal and petroleum are the main source of energy.
  • Helps to make geological timescale.
30
Q

Why are mineral Oil important?

A
  • Used as a lubricant
  • Used as a cooking oil.
  • Used in vehicles as a fuel
  • Used in many industries as fuel.
  • Mineral Oil such as Black Tar is used in construction of roads.
  • Used in manufacturing of plastics, chemical fertilizers, pesticides, paints, explosives, medicines etc.
31
Q

Write 5 importance of coal

A
  • Used in industries, houses and other places for heating and generating electricity.
  • Coal Tar obtained from coal is used in the manufacture of plastic
  • Used in steam engine to change water into steam.
  • Main source of national economy in some countries
  • Used for manufacturing petroleum and synthetic natural gas
32
Q
  1. Living beings were evolved very long after the earth was evolved, why?
A

The earth evolved 4.5 billion years ago. At the time of evolution of the earth, it was very hot and there was no suitable environment for the evolution and survival of living organisms. So, there were no life at the time of the evolution of the earth.

33
Q
  1. The first life on earth was originated in water why?
A

Studies that track how life forms have evolved suggest that the earliest life on Earth emerged about 4 billion years ago.
That timeline means life almost certainly originated in the ocean, Lenton says. The first continents hadn’t formed 4 billion years ago, so the surface of the planet was almost entirely ocean.

34
Q
  1. Natural gas is found mostly on the top of mineral oil in nature, why?
A

Gas has a lower density than oil and

oil have a lower density than water.

35
Q
  1. Mention the hypothesis propounded by Jeans and Jeffery about the origin of the solar system.
A

According to the hypothesis given by James Jeans and Jeffery in 1917 AD, tidal effect occurred on the sun when a big star orbiting round the sun approached it.

A large mass of gas was ejected from the sun due to the tidal effect. In the course of cooling, the tidal matter fragmented into small pieces forming planets, satellites etc. As a result the solar system was formed.

36
Q
  1. Write any 3 information obtained by the study of fossil.
A

Study of fossils:

  • helps us to discover the evolutionary trend of plants and animals on the earth
  • helps us to investigate the deposits of coal and petroleum inside the earths crust.
  • determine the age of rocks, to know geological history and to know about organic evolution on the earth.
37
Q
  1. Write 3 events which occurred in Mesozoic era
A

Evolution
–First coniferous and flowering plant
-Reptiles like turtle and large dinosaurs on land and water.
Extinction
-dinosaur at the end, and mammals began to evolve.

Development

  • suitable conditions on land, water and air for the survival of life took place.
  • Different types of hills and mountains were formed.
38
Q
  1. Write 3 events which occurred in Mesozoic era
A

Evolution
-Evolution of
-First coniferous and flowering plant
-Reptiles like turtle and large dinosaurs on land and water.
Extinction
-dinosaur at the end, and mammals began to evolve.

Development

  • suitable conditions on land, water and air for the survival of life took place.
  • Different types of hills and mountains were formed.
39
Q
  1. Write any 3 importance of mineral oil.
A
  • Used to run automobiles like truck, bus, car, motorcycle etc.
  • Used to operate various machines in industries.
  • Mineral oil is a colorless, oily, almost tasteless, water-insoluble liquid. It’s found in cosmetics, carrier oils, and lubricant laxatives. Its uses include moisturizing the skin; treating dandruff, cradle cap, cracked feet, mild eczema, and other skin problems; removing earwax; and relieving constipation
40
Q
  1. Mention any 3 importance of fossil.
A

Study of fossils:
-helps us to discover the evolutionary trend of plants and animals on the earth.

  • helps us to investigate the deposits of coal and petroleum inside the earths crust.
  • determine the age of rocks, to know geological history and to know about organic evolution on the earth.
41
Q
  1. Write any 3 ways of identification of fossils.
A
  • the impression of a while ore a part of any organ of dead bodies remains in hard ground or stone. Fossils are identified by studying these impressions.
  • The whole skeleton of animals and plants are pressed in rocks. Fossils can be identified from the study of such structures.
  • The fossils are also identified by the morphology of hard parts of organisms like teeth, bones, skeleton, shoot, leaves etc.
42
Q
  1. How was it know that there were dinosaurs on the Earth in ancient times?
    In which era were they dominant?
    What is the time duration of that era?
A

Everything we know about dinosaurs is based on fossils, which include bones, teeth, footprints, tracks, eggs, and skin impressions. For centuries, people throughout the world have discovered amazing fossilized bones and footprints.

ERA of Dominance: Mesozoic ERA

250 million years ago – 65 million years ago

43
Q
  1. Mention the time duration of Paleozoic and Cenozoic era. Write 2 major event that occurred in each era.
A

Palaeozoic ERA
570 million years ago – 250 million years ago
Cenozoic ERA
65 million years ago – till date

Palaeozoic ERA
Evolution
-of various aquatic and terrestrial plants.
-Climate suitable for living beings was developed due to change in water, land, atmosphere and weather.
-various aquatic and terrestrial invertebrates evolved.

Cenozoic ERA
Cenozoic Era major events including mass extinctions, the rise of mammals, changes in the climate, and the movement of continents into their present positions.

44
Q
  1. Write down the duration of Paleozoic era and enlist the major events of that era.
A

570 million years ago – 250 million years ago

Evolution

  • of various aquatic and terrestrial plants.
  • Climate suitable for living beings was developed due to change in water, land, atmosphere and weather.
  • various aquatic and terrestrial invertebrates evolved.
Development 
-some marine animals
-first marine vertebrate
-first reptiles
Evolution and development 
-fish
-insects having wings.
Evolution 
-first terrestrial green plants.
-crawling animals and amphibians
Extinction 
-different invertebrates and vertebrates.
45
Q
  1. Mention the major events in Mesozoic era regarding evolution of living beings.
A

Evolution of
-First coniferous and flowering plant
-Reptiles like turtle and large dinosaurs on land and water.
Extinction
-dinosaur at the end, and mammals began to evolve.

Development

  • suitable conditions on land, water and air for the survival of life took place.
  • Different types of hills and mountains were formed.
46
Q
  1. Write the name of era and its duration for each of the following incidents
    a) Evolution of human beings
    b) Evolution and extinction of dinosaur.
A

a) Evolution of human beings
Cenozoic ERA
65 million years ago – till date

b) Evolution and extinction of dinosaur.
Mesozoic ERA
250 million years ago – 65 million years ago

47
Q
  1. Describe the process of formation of fossil.
    OR,
    Describe the process of formation of mineral oil.
A

Fossil: are the preserved remains or traces of remains of ancient organisms. Fossils are not the remains of the organisms themselves, but are rocks. Bones, Shells, feathers and leaves can all become fossils.
- Formed in nature by the decomposition of parts of plants and animals that are buried under the earth surface for a long period of time.
- When the hard parts of plants and animals are pressed by sedimentary rocks under high temperature and pressure, various chemicals reactions occur and crude oil is formed.
- Mineral oil is then obtained from the purification of Crude Oil.
- In this way, fossil fuels or mineral oils are obtained by the purification of crude oil.
- -These fuels are obtained by drilling the holes in the earths surface.
Used as: Lubricants
Fuel for cooking food
Vehicles as fuel
Many industries as fuel
Construction of roads black tar

48
Q
  1. Describe the method of coal formation.
    OR
    Why is Coal called a fossil Fuel?

Where is Nepal do you find COAL?

A

Types of coal.
The hard, black or brown material which is found below the ground is called COAL.

The process of formation of coal from the parts of plants due to high temperature and pressures inside the earth is called CARBONIZATION.

4 Types of COAL:

a) Peat
b) Lignite
c) Bituminous
d) Anthracite [ Superior quality Coal]

COAL found in Nepal : DANG

  • In the ancient times, plant and animals were buried under the earths crust due to different geological phenomena like earthquake, volcano etc.
  • Then the remnants were pressed under high pressure and high temperature for a long time.
  • Elements like carbon, hydrogen and oxygen are present in the coal.
  • When a whole or part of a plant remains in swamp land in the form of a fossil for a long time, it is converted to coal.
  • The principal parts of plants are cellulose and lignin.
  • These are formed from protein, oil, organic acid and mineral oil etc.
  • Lignin plays an important role in the formation of coal.
49
Q
  1. Mention any eight important datas related to the Earth according to the World Book Encyclopedia.
A
  • Earths age : 4.5 x 109 years
  • Total Surface Area : 509,700.000 km2
  • Part of land : 148400,000 km2
  • Part of water : 361,300,000 km2
  • Diameter : 12756.3 km
  • Main Gases : N2, O2, CO2
  • Average relative density : 5.5 g/cm3
  • Mass : 6 x 1021 metric ton
  • No. of satellite : 1 (moon)
  • Position : Earth is the 3rd from the sun
  • Squashed Shape : Earth is not a perfect sphere
  • Earths Waistline : Planet has a waistline
  • On the move : Earth moves around the Sun
  • Moonquakes : Earth quakes on the moon
  • States of Matter : Only place in the solar system where water can be present in all 3 states (Solid, liquid & Gas)
  • Earths Ocean : more than 95% of Earth’s Ocean are still unexplored.
  • Species : 99% of all species that ever existed on Earth are now extinct.
  • Inner Core : Earths inner core has a temperature between 5400 to 6000 degree Celsius.
  • Layer : Thickest of all 4 layers is mantle
  • Layer : Thinnest of all 4 layers is crust
  • Satellite : Moon is Earths only permanent natural satellite
50
Q
  1. What are the two conditions required to form mineral oil inside the Earth’s crust? Draw a labelled diagram showing the process of formation of mineral oil.
A
  • Lack of oxygen

- There should be heat and pressure to turn the organic matter into Kerogen (a waxy material)

51
Q

What is mineral fuel /Crude Oil? Reason to minimize consumption of mineral oil in Nepal

A

The mixture of hydrocarbons and other substance like oxygen, nitrogen and sulphur formed from fossil is called crude oil.

It’s a non renewable source of energy and it also pollutes the environment when burnt.

52
Q
  1. Write down the duration of Mesozoic era and describe the origin of organisms on this era
A

Dominance of reptiles like turtles, dinosaurs on the land and water. Called the era of golden age of reptiles.

53
Q
  1. Write short notes on
    Nebular Hypothesis :
    Tidal Hypothesis :
A

Nebular Hypothesis :
The nebular Hypotheses:
-first introduced by German philosopher Kant in 1755 AD and
-Later modified by French Mathematician Laplace in 1976 AD
Since then it is called Kant-Laplace hypothesis.

It is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems).

  • Everything right from the sun, asteroids, planets have all been created by nebula cloud.
  • Stars were formed way before asteroids, planets came into existence.
  • The biggest star is the SUN.
  • Initially there was a nebula cloud which made of helium, hydrogen and other sorts of dust particles,
  • This cloud started rotating very heavily.
  • Because of that most of the heavy particles , hydrogen and helium elements came to the center and started colliding with each other and due to the friction and collision of particles, fusion reaction took place and pure Energy started generating and this created the SUN.
  • If lighter elements went to the center, the heavier moved away from the center like Carbon, Oxygen, Phospohorus, Nitrogen, Iron, Silicon etc. If you see the earth and all the planets, are made of dense elements than STARs.
  • These heavier elements started forming small clumps of clouds, smaller nebular with further rotation, friction and collision of particles. Which lead to formation of a disc shaped cloud and the planets were formed.

Tidal Hypothesis :
Tidal Hypothesis : James Jeans and Jeffery
Jeans and Jeffery in 1917 AD
Tidal effect occurred on the sun when a big star orbiting round the sun approached it.
A large mass of gas was ejected from the sun due to the tidal effect.
In this course of cooling, the tidal matter fragmented into small pieces forming planets. Satellites etc.
As a result the solar system was formed.
OR,

The British scientists James Jeans and Harold Jeffery in 1917 A.D. explained the origin of the solar system as a result of a close encounter between the Sun and the second star. As a result of detailed mathematical analysis, Jeans concluded that the tidal interaction between the Sun and the passing star caused great attraction and would raise tides on the Sun resulting in the loss of a single cigar-shaped filament of hot gas.
Then, the tidal hot matter fragmented from the sun and the fragmented particles cooled down. These particles revolved around the sun. in this way solar system was created.

54
Q
  1. Mention the duration of palaezoic era. Explain about the origin of organism in palaezoic era shortly
A

Palaeozoic ERA
570 million years ago – 250 million years ago

Arthropods, molluscs, fish, amphibians, synapsids and diapsids all evolved during the Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, it was dominated by various forms of organisms.

Development 
-some marine animals
-first marine vertebrate
-first reptiles
Evolution and development 
-fish
-insects having wings.
Evolution 
-first terrestrial green plants.
-crawling animals and amphibians
Extinction 
-different invertebrates and vertebrates.
55
Q
  1. Short notes
    Pre Cambrain Era:
    Mesozoic Era
A

Pre Cambrian ERA
Origin – 570 million years ago
Evolution of Algae and bacteria
-Existence of bacteria about 3.8 billion years ago and moss before 3.2 billion years ago.
-Evolution of unicellular organisms
-Development of multicellular organisms.

Mesozoic Era
250 million years ago – 65 million years ago
Era of Reptiles
Era of Creepers

Evolution of 
-First coniferous and flowering plant
-Reptiles like turtle and large dinosaurs on land and water.
Extinction 
-dinosaur at the end, and mammals began to evolve. 
Evolution 
-as above.
Development
-suitable conditions on land, water and air for the survival of life took place.
-Different types of hills and mountains were formed.
Time
-Dominance of dinosaurs in this era
-Human beings absent
Crocodiles 
Coniferous Plants
Dinosaur
Reptiles

ASTRONOMY (1 decks)

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