How have human activities caused desertification? Explain.
Human activities like over- cultivation, unrestricted grazing, deforestation and poor irrigation practices, resulting in arid patches of land. The open lands without any cover of vegetation is prone to soil erosion. The soil erodes and becomes incapable of providing nutrition to the plants. The land become barren over the years These large barren patches extend and meet over time to create a desert.Rapid urbanisation has led to the desertification.
Differentiate between inbreeding and outbreeding in cattle. State one advantage and one disadvantage for each one of them.
Describe the structure of a RNA polynucleotide chain having four different types of nucleotides.
(a) Draw a diagrammatic sectional view of a mature anatropous ovule and label the following parts in it:
(i) that develops into seed coat.
(ii) that develops into an embryo after fertilization.
(iii) that develops into an endosperm in an albuminous seed.
(iv) through which the pollen tube grains entry into the embryo sac.
(v) that attaches the ovule to the placenta.
(b) Describe the characteristic features of wind pollinated flowers.(a) Why are transgenic animals so called?
(b) Explain the role of transgenic animals in
(i) Vaccine safety
(ii) Biological products with the help of an example each.
Explain mutualism with the help of any two examples. How is it different from commensalism?
(a) Why is human ABO blood group gene considered a good example of multiple alleles?
(b) Work out a cross up to F1 generation only, between a mother with blood group A (Homozygous) and the father with blood group B (Homozygous). Explain the pattern of inheritance exhibited.
With the help of any two suitable examples explain the effect of anthropogenic actions on organic evolution.
(a) Why are the fruit juices bought from market clearer as compared to those made at home?
(b) Name the bioactive molecules produced by Trichoderma polysporum and Monascus purpureus.
