Q29 of 30 Page 1

Explain the salient features of Hugo de Vries theory of mutation. How is Darwin’s theory of natural selection different from it? Explain.

OR


(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 earth. State the brain capacity of each one of them.


(iii) When did modern Homo sapiens appear on this planet?


Hugo de Vries worked on the plant Evening Primrose and found out various things about mutation and proposed a theory of mutation whose some of the salient features are

i) Mutations are discontinuous variations.


ii) Mutations occur suddenly and causes speciation.


iii) Mutations can occur in number of individuals in the same species.


iv) Mutations occur in all conceivable directions.


v) All mutations are inheritable.


vi) Mutation causes evolution and not the minor variations(heritable).


vii) Mutations are random and directionless.


Whereas Darwin after his research on Darwin finches on the Galapagos islands concluded that mutations are directional, small and show branching descent and natural selection.


OR


a) The primates that existed approx. 15 million years ago were Dryopethicus.


Some characteristic features are:-


1) Looked more like apes but had arms and legs.


2) Semi-erect posture.


3) Large brain size and canines.


4) No browridges.


5) Arboreal and knuckle walker.


6) Ate soft fruits and leaves.


b) i)First man like animal was found in Sahara grasslands of African continent.


ii) The series in which they appeared are:-


Homo habilis (650-800 cc)


Homo erectus (about 900 cc)


Neanderthals (1400 cc)


iii) Homo sapiens arose during the ice age approx. around 75000-10000 years ago.


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26

How can crop varieties be made disease resistant to overcome food crisis in India? Explain. Name one disease resistant variety in India of:

(a) Wheat to leave and stripe rust


(b) Brassica to white rust


OR


Write the source and the effect on the human body of the following drugs:


(i) Morphine


(ii) Cocaine


(iii) Marijuana


 27

Name the type of interaction seen in each of the following examples:

(i) Ascaris worms living in the intestine of human.


(ii) Wasp pollinating fig inflorescence.


(iii) Clown fish living among the tentacles of se-anemone.


(iv) Mycorrhizae living on the roots higher plants.


(v) Orchid growing on a branch of a mango tree.


(vi) Disappearance of smaller barnacles when Balanus dominated in the Coast of Scotland.


 28

(a) Draw a labelled diagram of the human female reproductive system.

(b) Enumerate the events in the ovary of a human female during:


(i) Follicular phase


(ii) Luteal phase of menstrual cycle
OR


(a) Write the specific location and the functions of the following cells in human males:


(i) Leydig cells


(ii) Sertoli cells


(iii) Primary spermatocyte


(b) Explain the role of any two accessory glands in human male reproductive system.


 30

(a) Explain primary productivity and the factors that influence it.

(b) Describe how to oxygen and chemical composition of detritus control decomposition.


OR


(a) What is El Nino effect? Explain how it accounts for biodiversity loss.


(b) Explain any three measures that you as an individual would take, to reduce environmental pollution.