Biology Flashcards
(58 cards)
What does the Panspermia hypothesis propose?
The Panspermia hypothesis argues that life originated in some other planet in the universe and accidentally reached the Earth.
Who are the proponents of the theory of chemical evolution?
The proponents of the theory of chemical evolution are A.I. Oparin (1924) and J.B.S. Haldane (1929).
What is the basis of the theory of chemical evolution?
The theory of chemical evolution suggests that life originated as a result of changes in chemical substances in seawater under specific conditions on primitive Earth.
What gases were present in the atmosphere of primitive Earth?
The atmosphere of primitive Earth contained gases like hydrogen, nitrogen, carbon dioxide, methane, ammonia, water vapor, and hydrogen sulfide.
What were the simple organic molecules formed on primitive Earth?
Simple organic molecules included amino acids, monosaccharides, nitrogen bases, and fatty acids.
What led to the formation of oceans on primitive Earth?
The condensation of water vapor present in the atmosphere and the resulting incessant rain led to the formation of oceans.
What are some sources of energy that contributed to chemical evolution?
Sources of energy included thunder and lightning, ultraviolet radiations, and volcanic eruptions.
What complex organic molecules were formed during chemical evolution?
Complex organic molecules included proteins, polysaccharides, nucleotides, and lipids.
What was the scientific basis of the hypothesis regarding the origin of life?
It was later proved through various experiments.
What experiment did Urey and Miller conduct?
They artificially recreated the atmosphere of primitive Earth containing methane, ammonia, hydrogen, and water vapour.
What energy sources were used in the Urey-Miller Experiment?
High voltage electricity was passed through the gaseous mixture instead of natural energy sources like thunder and lightning.
What were the main components used in the Urey-Miller Experiment?
Methane, ammonia, hydrogen, and water vapour.
What was found after the sediment substances were separated in the Urey-Miller Experiment?
Organic molecules such as amino acids were found.
What hypothesis gained more acceptance due to the Urey-Miller Experiment?
The Oparin-Haldane Hypothesis.
What process led to the formation of organic compounds in the oceans of primitive Earth?
Chemical evolution that continued for millions of years.
Who conducted the Urey-Miller Experiment?
Stanley Miller and Harold Urey.
What is the main quest of many space explorations?
To find out whether similar phenomena occur anywhere else among the millions of celestial orbs.
What is the method of science?
Formulation of inferences on the basis of evidences obtained through experiments and observations.
When did science emerge?
Science emerged along with the origin of human beings.
Why are direct evidences not available for explaining the origin of life?
Because the process of evolution began a long time before the origin of man.
What happens to scientific concepts in the areas of origin of life and evolution?
They undergo continuous changes.
What makes science credible?
Science is unprejudiced and accepts all new knowledge formulated on the basis of derived evidences, rejecting or revising existing ones.
