Q15 of 43 Page 1

Charles Darwin during his famous sea voyage around the world in a ship (HMS Beagle), concluded that there has been gradual evolution of life.

Answer the following questions:


(a) What is his theory known as? Explain the salient features of his theory.


(b) Name a scientist who arrived at a similar conclusion as that of


Charles Darwin.


a) The theory is known as ’Darwinian Theory of evolution’. Salient features of this theory are:


1. There were varying degree of similarities between the existing and the life forms that existed million of years ago.


2. The evolution has been gradual which came at different time.


3. There is only the survival of the fittest .


4. The population that will survive better in the natural conditions will survive better than the others known as natural selection.


5. Adaptability is inherited and fitness is the end result of ability to adapt.


b) Alfred Russel Wallace was also a scientist who proposed the theory of evolution by natural selection.


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13

(a) A patient had suffered myocardial infarction and clots were found in his blood vessels. Name a ‘clot buster’ that can be used to dissolve the clots and the micro-organism from which it is obtained.

(b) A woman had just undergone a kidney transplant. A bioactive molecular drug is administered to oppose kidney rejection by the body. What is the bioactive molecule? Name the microbe from which this is extracted.


(c) What do doctors prescribe to lower the blood cholesterol level in patients with high blood cholesterol? Name the source organism from which this drug can be obtained.


 14

Give reasons for the following:

(a) Antibody mediated immunity is called humoral immunity.


(b) How is a child protected from a disease for which he/she is vaccinated?


(c) Name the type of cells the AIDS virus enters after getting into the human body.


OR



(a) Identify the nos. (i) to (iv) in the following table:


(b) Which ones of the above mentioned diseases are transmitted through mechanical carriers?


 16

Draw a diagram of LS of Maize grain and label its any six parts.

 17

A woman with ‘O blood group’ marries a man with ‘AB blood group’. Work out the cross to show all the possible phenotypes and genotypes of the progeny with respect to blood groups. Explain the pattern of inheritance observed in this cross.