Long Answer Type(a) Explain four measures to control population explosion.
(b) Write the causative agent and main symptoms of the following diseases
(i) Tuberculosis (ii) Tetanus
(iii) Hepatitis (iv) Malaria
(c) Write two differences between benign tumour and malignant tumour.
(a) Define:
(i) Vestigeal organs
(ii) Sympatric speciation
(iii) Mutagens
(iv) Biogeography
(b) Archaeopteryx is considered a connecting link between reptiles and birds. Justify the statement by giving two characteristics of each group.
(c) Give two differences between natural selection and artificial selection.
a) Write four characteristics that have developed during human evolution.
(b) What are stem cells? Write two applications of stem cell in medical treatment.
(c) Mention three basic ways to conserve plant resources.
(a) Four characteristics that have developed during human evolution are:
(i) Erect Posture with four reused curves in the spine.
(ii) An upright head having eyes facing in front.
(iii) Straight limbs with arms shorter than legs.
(iv) Fingers and toes had flat nails in place of claws.
(b) Stem cells are undifferentiated cells of a multicellular organism which are capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation.are characterised by the ability to renew themselves through mitotic cell division and differentiating into a diverse range of specialised cell type.
• Stem cells are being used in cancer therapy.
• Stem cell is used to make different muscles.
(c) In situ conservation means maintaining plant diversity in natural reserves it protects the species threatened with loss or Extinction, supply materials to restore degraded lands and provide materials for genetic improvement of crop plants. It is mostly done by establishing biosphere reserves.
Ex situ conservation crucial Besides the primary repositories for wild plants, botanical gardens have a crucial role both in conservation and education.
Gene Banks: A gene bank is an institution where valuable plant material likely to become irretrivably lost in the wild or in cultivation is preserved in a viable condition gene bank consume stocks of both seeds and vegetative material. The stored germplasm not only safeguard the species threatened with loss or extinction but is also actively utilized the world over by breeds to develop novel varieties.
Cryopreservation - Cryopreservation (preservation in liquid nitrogen, -196°C) of plant germplasm. The term 'cryopreservation' (cryogenic preservation) refers to the storage of cells, tissues and organs at the ultra-low temperature of liquid nitrogen (-196°C).
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