Long Answer Type(a) Give any three characters that have developed during human evolution.
(b) Explain the term chemogeny.
(c) Give any two distinctive features of Dryopithecus.
(a) Explain the evolution of giraffe’s neck according to Lamarck’s theory of evolution.
(b) Give two chromosomal similarities between man and apes.
(c) Name any two temporary embryonic structures in vertebrates which provide evidence for evolution.
(a) According to the Lamarck's theory of evolution:
Giraffes have evolved to have a long neck because of the continuous use of the organs.
The theory says:
i. The giraffes had evolved from the deer-like ancestors which were small in height and had short necks.
ii. The giraffes had a short neck and short forelimbs and grazed on grass.
iii. When the ground vegetation was consumed completely and was exhausted, the giraffes tried to reach the leaves on the higher branches of the trees.
iv. They stretched their necks and forelimbs continuously to reach the food. v. This resulted in gradual elongation of the neck and the forelimbs.
v. The trait of the long necks was then transmitted to the next generation. This is how the giraffes acquired long neck.
(b) Chromosomal similarities between man and apes are:
i. Almost similar chromosomal number 23 pairs in man and 24 pairs in apes.
ii. Similar banding pattern of chromosome 3 and 6.
(c) Two temporary embryonic structures which provide evidence for evolution are:
i. Gill clefts develop in the embryo of all land vertebrates.
ii. Embryo of all vertebrates develops a notochord which is replaced by a vertebral column in the adults.
(a) Persons suffering from sickle cell anaemia are at an advantage in Malaria infested areas. Explain.
(b) Define the term gene flow.
(c) What are analogous organs? Describe with one example from the plant kingdom.
(a) With the help of diagrams, name and describe the different types of placentation seen in angiosperms.
(b) Give four points of anatomical differences between a monocot stem and a dicot stem.
(c) Define the following terms:
(i) Racemose inflorescence
(ii) Osmotic pressure
(a) Draw a diagram of the internal structure of the human ovary.
(b) Define the term water potential.What are its components? Explain.
(c) Give definition and importance of:
(i) Imbibition
(ii) Parturition
(a) Give four adaptations in flowers pollinated by insects.
(b) Describe the mass flow hypothesis for translocation of organic solutes (food) in plants.
(c) Write a brief note on the causes of infertility.
(a) Give any four reasons for Mendel’s success.
(b) Briefly describe the technique employed in DNA fingerprinting.
(c) Give any two features of Genetic Code.
(a) Explain the mechanism of action of T cells to antigens.
(b)Explain how insulin can be produced using recombinant DNA technology.
(c) What is pisiculture? Give one advantage.
(a)Name the causative organism andpreventive measures for each of the following:
(i) Swine flu
(ii) Typhoid
(iii) Filariasis
(iv) Syphilis
(b)State four causes and four consequences of population growth.
(c)Differentiate between:
(i)Cannabinoids and Barbiturates
(ii)Biotic potential and Carrying capacity
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