(a) List the various causes of variations in the progeny of a population.
(b) Describe the three different ways in which natural selection operates in nature, with regard to organic evolution.

5

(a)

(a) Name the primates that lived about 15 million years ago. List their characteristic features.
(b) (i) Where was the first man-like animal found?
(ii) Write the order in which Neanderthals, Homo habilis and Homo erectus appeared on the earth. State the brain capacity of each one of them.
(iii) When did modern Homo sapiens appear on this planet?

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(a)

(a) Explain taking one example of vertebrate anatomy, that evolution of life has occurred on earth.
(b) 'Nature selects for fitness'. Explain with suitable example.

5

(a)

Name the law that states that the sum of allelic frequencies in a population remains constant. What are the five factors that influence these values?

5

(a)

Two organisms occupying particular geographical area show similar adaptive strategies. Taking examples, describe the phenomenon.

5

(a)

One day, while returning home from school, Anil saw a crowd gathering front of Mr. Sharma's house. He asked his mother about it. She told that Mrs. Sharma gave birth to a child with small tail. Many people gathered just for curiosity and some whispered that it is a bad omen.
Read the above passage and answer the following questions:
(i) What is your opinion about child?
(ii) What is atavism?
(iii) What will be your role as a good citizen and student of biology?

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(a)

State the modifications of forelimb in animals as an example of homology.

5

(a)

(i) List any four evidences of evolution.
(ii) Explain any one of the evidences that helps to understand the concept of evolution.

5

(a)

How they are considered as an evidence of evolution.

5

(a)

(a) Write Hardy-Weinberg principle.
(b) Explain the three different ways the natural selection can affect the frequency of a heritable trait in a population shown in the graph given below.

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(a)