5. Origin And Evolution of life

 

Q. 1: What is life?

Ans.: Life is an inherent capacity that an organism possesses to maintain and reproduce itself.

Q.2: Name two basic events in the history of life.

Ans.: First is the origin of life and second is the evolution of life.

Q. 3: What is big bang?

Ans.: A fiery explosion which resulted in the big bang sound and release of cosmic condensed matter scattered in the form of fragments is big bang theory.

Q. 4: Who proposed big bang theory?

Ans.: Abbey Lemaitre proposed big bang theory in 1931.

Q.5: When did earth form?

Ans.: The earth formed about 4.6 billion years ago.

Q.6: What is   protobiogenesis?

Ans.: The origin of life on earth is known as protobiogenesis?

Q.7: Define a biogenesis?

Ans.: Origin of life from non-living things in a spontaneous manner is known as a biogenesis

Q.8: Explain various theories of origin of life.

Ans.: The different theories can be explained as under:-

A) Theory of Specie Creation:

1) This concept has no scientific support.

2) The theory suggests that God or Creator or super natural power created life on earth. It supports divine creation of life.

3) The theory states that all life created as such of nothing and all of sudden.

4) All living organisms never explain or show any kind of relationship among them.

5) The life is immutable and showed no change since their formation.

6) Hebrew and Spanish Monk Father Suarez strongly support this theory on the basis of chapter Genesis in Bible.

Hindu mythology also supports this theory and considers “Brahma” as Creator of world.

7) However, this theory was strongly rejected in the focus of modern evolution theories.

B) Cosmozoic Theory / Inter planetary Theory:

1) Richter proposed this theory and was supported by Arrhenius.

2) The theory suggests that life came on the earth from some other planet or the solar system.

3) It was in the form of spore or seed called as panspermia or spore theory.

4) However, theory failed to explain the mechanism of panspermia.

5) The idea or concept of meteorites (masses of matter from outer space) was given and stated that such meteorites struck the barren land to release cosmozoa and helped in the development of different types of living organisms.

 

C) Theory of spontaneous or theory of abiogenesis or auto biogenesis:-

1) Van Helmont proposed theory of abiogenesis.

2) The theory is based on the postulate that life originated abiogenetically from non-living, decaying, rotting, matter such as straws, mud etc. by spontaneous generation about 3.5 million year ago.

3) The different examples given are as follows:

a) Anaximander considered

b) Aristotle proposed that different insects, fishes, frogs and even mice develops from soil and filth Animal excreta produced flatworms, crabs whereas salamanders, frog etc., from earth and slime.

c) Grotius developed from white, horse tail.

d) Mud from Nile River produced different organisms when warmed in summer.

e) Human sweat and wheat produced both sexes of mice.

f)  Insects developed from dew and dogs from muddy bottom of ponds.

4) However, this theory was rejected by Francisco Reid, Louis Pasture and Spallanzani.

D) Theory of Biogenesis:

1) The theory strongly suggests that life originated from preexisting life only.

2) Francisco Reid founded this theory of biogenesis.

3) Redi Concluded from his experiment on mug guts and meat that maggots arise from eggs and not from decaying meat.

4) Spallanzani (1729-1799) from his experiment concluded that air contains microbes and all the microbes develop from preexisting microbes only.

5) Louis Pasteur tried to show that protists and bacteria develop from organisms of same kind.

6) Final conclusion from all experiment was in support of theory of biogenesis.

Q. 9: Who proposed the theory of special creations?

Ans. Spanish Monk Father Suarez proposed theory special creation.

Q.10: Who proposed the cosmozoic theory?

Ans. Richter in 1865 proposed cosmozoic theory.

Q.11: What is panspermia or cosmozoa?

Ans. According to cosmozoic theory life on earth existed from distant planet in the form of spores and microorganisms. These are called as cosmozoa or panspermia.

Q. 12: What is autobiogenesis?

Ans.: Origin of life from non –living material by spontaneous generation is called as autobiogenesis.

Q.13: What is biogenesis?

Ans.: Origin of life from preexisting life forms of the   same kind is known as biogenesis.

Q. 14: Who proposed autobiogenesis?

Ans.: Von Helmont proposed theory of auto biogenesis.

Q.15: Who proposed the concept of modern self-assembly theory?

Ans.: Lininger (1970), Fox and Dose (1972) and Fox (1968) proposed concept of modern self-assembly theory.