EVOLUTION Flashcards
(42 cards)
Define the term ‘evolution’.
It refers to the gradual changes in living organisms over time.
Define Evolutionary Biology.
It is defined as the study of the history of life-forms on earth.
When the process of evolution actually begin?
Evolution began only after the origin of the earth.
Which theory explains the origin of the earth and who proposed it?
The BIG BANG THEORY explains the origin of the earth. It was proposed by Lemaitre.
Explain the Big Bang Theory.
At the beginning of time, the world was believed to a point. This point then explodes about 200 billion years ago which lead to the formation of matter and energy.
How were the different states of matter formed?
During the expansion of the universe, the temperature dropped leading to the condensation of matter.
Which was the first formed matter/ element?
Hydrogen.
Explain the formation of the universe.
Several interactions that include the fusion and condensation of big cosmic clouds lead to the formation of the galaxy. Many such galaxies form the milky way and many such milky ways formed the universe.
How was the solar system originated?
It happened due to the condensation of a cosmic cloud, as per the Condensation Theory or Nebular Hypothesis of Immanuel Kant.
How did the planets and the sun form?
The sun developed from a large whirling mass of cosmic material or a nebula while the planets developed from smaller peripheral condensed cosmic material.
Why did only the central mass become the sun?
Because only this mass had a critical temperature for thermonuclear reactions to occur.
When was the earth formed?
The earth was formed about 4.5 billion years ago.
What do you mean by the density gradient of cosmic material in the solar system?
It means that the clouds with heavier elements condensed nearer to the sun while the clouds with lighter and volatile elements, away from the sun.
How was primitive earth?
Primitive Earth was like a ball of gases of various elements. The heavier elements were found near the core and vice-versa. It had extremely high temperatures, volcanic storms, extreme climate with UV rays.
Explain the difference in the atmosphere now and then.
Today the atmosphere is an oxidizing one while earlier it had been a reducing one.
What is protobiogenesis?
It is the origin of life on the primitive earth.
Which theory suggests that the earth is a gift of the almighty?
The theory of Special Creation. But it did not support the theory of evolution as it is a purely religious concept.
Explain the theory of catastrophism.
It is a modification of the Special-Creation theory. It explains that several creations of life by God proceeded by a catastrophe i.e. each catastrophe completely destroyed existing life making way for new.
Which theory was dropped by H E Richter in 1865 and supported by Arrhenius?
The cosmozoic theory states that life reached on earth through heavenly bodies such as meteorites in the form of resistant spores. It works for many astronomers but not scientists.
Which theory explains that life on earth originated from non-living matter?
The theory of spontaneous generation or abiogenesis. It is supported by Aristotle. He thought that dead leaves became fish in water and in the soil became worms.
What was Von Helmont’s ridiculous claim?
He claimed to have made a soup that could generate rats spontaneously. This soup consists of a dirty cloth soaked in water with wheat grains and human sweat is added to it as an activator.
What did Pastuer’s experiments prove?
It was a continuation of Spallanzani’s experiment to prove that microbes arise from pre-existing ones.
What is the specialty of Pasteur’s experiments?
He used a weird swan-necked flask for his experiment. These flasks allowed air into it but not the particles from the air.
What is the other name of the Physicochemical Theory or Materialistic Theory?
The Theory of Primary Abiogenesis i.e. first life from non-life but thereafter life from pre-existing life.
