Q25 of 27 Page 1

People living in the coastal areas are forced to evict their dwelling units as the sea has inundated into the land areas. State the possible reasons and suggest measures that could be taken to reduce the deleterious changes in the environment.

OR


A young sperm whale, 33-foot long was found dead off the coast. It had a large amount of human trash like trash bags, polypropylene sacks, ropes, net segments etc. amounting to 29 kilograms in its digestive system. The whale died because of inflammation of the abdominal lining. Analyze the possible reasons for such mishaps and suggest measures that can be taken to reduce such incidents.

Increase in the greenhouse gases has led to heating the earth leading to global warming. The scientist believes that the rise in temperature is leading to the deleterious changes in the environment which bring odd climatic changes. Thus melting the polar ice caps and other places like Himalayan snow caps. If this continuous for a long period; the sea level significantly rises and can submerge many coastal areas. Thus forcing the inhabitants of coastal areas to evict their dwelling units.

OR


The possible reasons for such mishaps are due to the increasing solid wastes and their improper disposal. Buring these trash bags, polypropylene sacks, ropes, net etc were the first option to reduce their volume; but unburnt materials serve as breeding ground for flies and rats. The second method of disposal adopted was sanitary landfills, but due to high generation of garbage in metro cities resulted in continuous filling of landfills. Eventually, humans turned to use the remaining open source i.e. the rivers and oceans for waste disposal. This turns out to be dangerous for aquatic life. Fishes start to feed on this plastic bag, sacks, ropes, nets, etc. They are hence leading to their death. Careless behaviour of throwing useless nets, ropes etc by fisherman, depositing solid waste to channels of water that eventually runs to seas and oceans are all various reasons for the threat caused to aquatic life.


Measures to avoid such mishaps:


• Refuse the use of polythene bags.


• Recycling the solid waste


• Treatment of waste water before being released to natural water bodies.


• Proper waste disposal systems need to be introduced.


• Switch on to natural fibre carry bags.


• Strict bans on contaminating water bodies with trash.


More from this chapter

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23

Study the given pedigree chart and answer the questions that follow:


(a) Is the trait recessive or dominant?


(b) Is the trait sex-linked or autosomal?


(c) Give the genotypes of the parents shown in generation I and their third child shown in generation II and the first grandchild shown in generation III.


OR


Haemophilia is a sex-linked recessive disorder of humans. The pedigree chart given below shows the inheritance of Haemophilia in one family. Study the pattern of inheritance and answer the questions given.


pedigree.png


(a) Give all the possible genotypes of the members 4, 5 and 6 in the pedigree chart.


(b) A blood test shows that the individual 14 is a carrier of haemophilia. The member numbered 15 has recently married the member numbered 14. What is the probability that their first child will be a haemophilic male.? Show with the help of Punnett square.

 24

(a) In a pond, there were 200 frogs. 40 more were born in the year. Calculate the birth rate of the population.

(b) Population in terms of number is not always a necessary parameter to measure population density. Justify with two examples.

 26

Aneuploidy of chromosomes in human beings results in certain disorders. Draw out the possibilities of the karyotype in common disorders of this kind in human beings and its consequences in individuals.

OR


In a dihybrid cross, white-eyed, yellow bodied female Drosophila was crossed with red-eyed, brown bodied male Drosophila. The cross produced 1.3 per cent recombinants and 98.7 progeny with parental type combinations in the F2 generation. Analyze the above observation and compare with the Mendelian dihybrid cross.

 27

Differentiate between spermatogenesis and oogenesis.

OR


‘Parturition is induced by a complex Neuro endocrine mechanism’. Justify