Define Evolution. How Does It Occur? - Science


Define evolution. How does it occur?



Evolution is the formation of more complex organisms from pre-existing simpler organisms over a certain period. Accumulation of variation in genetic material forms the basis of evolutionary processes.

Concept: Evolution
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2015-2016 (March) All India Set 3

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"We cannot pass on to our progeny the experiences and qualifications earned during our life time". Justify the statement giving reason and examples.

Insects, octopus, planaria and vertebrates possess eyes. Can we group these animals together on the basis of eyes that they possess ? Justify your answer giving reason.

 In what way are homologous organs evidence for evolution?


Which of the following gas was not present in early earth atmosphere?
(a) Ammonia
(b) Oxygen
(c) Hydrogen sulphide
(d) Methane


According to scientists, aves have evolved from :
(a) mammals
(b) amphibians
(c) reptiles
(d) arthropods

Out of the wing of a bird, wing of an insect and the wing of a bat :
 which two are analogous organs?

State the meaning of inherited traits and acquired traits. Which of the two is not passes on the next generation? Explain with the help of an example.

Read the following statement and justify same in your own words with the help of suitable example.

Human evolution began approximately 7 crore years ago.

Read the following statements and justify same in your own words with the help of suitable examples.

Study of fossils is an important aspect of study of evolution.

Complete the statement by choosing correct options from below .

Evolution means -- -- -- --.

Write short notes based upon the information known to you.


 Explain the following :

(a) Speciation

(b) Natural Selection 

List two differences between acquired traits and inherited traits by giving an example of each.

Very short answer question.

Define Organic evolution.

Fill in the blank.
The first systematic explanation of the concept of evolution was given by _______________.

The sequence of gradual changes which takes place in the primitive organisms over millions of years in which new species are produced is known as ______ 

The chronological order of human evolution from early to recent stages is ______.

The first fossil of human form, discovered was ______.


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