ORIGIN AND EVOLUTION OF LIFE

Question 1

means the appearance of
simplest primordial life from non-living
matter.

Answer 1

origin of life

Question 2

means the gradual
formation of complex organisms from
simpler ones.

Answer 2

evolution of life

Question 3

It states that life migth have first originated
on earth through a series of combinations of
chemical substances in the distant past and
it all happened in water.

Answer 3

Chemosynthetic Theory of Origin of Life

Question 4

Chemosynthetic Theory of Origin of Life was proposed by

Answer 4

Alexander Ivanovich Oparin

Question 5

the source of energy - ultraviolet rays or
electric discharge (lightening) or heat or a
combination of these caused reactions that
produced complex organic compounds

Answer 5

first stage

Question 6

simple organic molecules combined to form large molecules which included peptides (leading to the formation of proteins), sugars, starches and fat molecules.

Answer 6

second stage

Question 7

the large molecules of different kinds combined together to form multi-molecular heaps and complexes.

Answer 7

third stage

Question 8

It is also believed that RNA molecules might have shown
enzymatic activity in the “primordial soup” of chemical
compounds. Such molecules have been termed ________

Answer 8

ribozymes

Question 9

some sort of nucleoproteins or nucleic acids may have evolved by random
combinations which have provided two or more properties to coacervate like
bodies.

Answer 9

fourth stage

Question 10

The formation of complex organisms through ‘change’ from simple ancestral types over the course of geological time.

Answer 10

evolution

Question 11

The various present day organisms were not
created in the same form in which they exist today, but have gradually evolved from much simple ancestral forms of a common ancestor.

Answer 11

Theory of Organic Evolution

Question 12

Though organisms of different species and
groups are quite different from each other
still they retain certain common features.

Answer 12

evidences from morphology

Question 13

are the organs which are similar in structure and origin but may look very different and perform different functions.

Answer 13

homologous organs

Question 14

The structure which are functionally similar but
structurally different are called _________

Answer 14

analogous organs

Question 15

is any small degenerate
or imperfectly developed
(non-functional) organ or part which may have been complete and functional in
some ancestor.

Answer 15

vestigial organs

Question 16

The animals or plants which possess characters of two different groups of
organisms are knowns as

Answer 16

connecting links

Question 17

is the study of development
of an orgnanism

Answer 17

embryology

Question 18

the embryos of all vertebrates are similar in shape and structure in their
early stages.

Answer 18

evidences from embryology

Question 19

is the study of fossils.

Answer 19

paleontology

Question 20

The fossils discovered provide the ancestral history of individual. Animals like horse, camel etc. are direct proofs of organic evolution. This can be very well illustrated by the past history of horse.

Answer 20

evidences from paleontology

Question 21

All organisms have cell as the basic unit of life. The cell is made of biomolecules.

Answer 21

molecular evidence of evolution

Question 22

still holds ground
but was modified with progress in genetics and
developed into the Modern synthetic theory which is
regarded as the most valid theory of evolution.

Answer 22

Darwin’s Theory of Natural Selection

Question 23

which is a sudden genetic change.

Answer 23

mutation

Question 24

which occurs in sexually reproducing organisms at every reproduction. The chromosomes and thus
genes of the parents mix at random during zygote formation.

Answer 24

genetic recombination

Question 25

when there is chance for mixing of genes of closely related species through sexual reproduction.

Answer 25

gene flow

Question 26

occurs in small populations when it breaks off from a large population only
representative genes of the large population are
present which undergo change and the small
population may evolve as a result.

Answer 26

genetic drift