Ecosystems — BIOLOGY STD 12 Science — Question

Write the type and location of the gene causing thalassemia in humans. State the cause and symptoms of the disease. How is sickle cell anaemia different from this disease?

Ramesh visited a National Park on a school trip where he saw tiger eating a deer. He got disturbed and asked his teacher why is he doing so. His teacher replied that it is natural population controlling phenomenon.

1. Which type of interspecific interaction is found between tiger and deer?
2. State the role of predators.
3. What other type of population interactions are seen in nature?
4. State the values of Ramesh towards animals.

As we know, our rivers Ganga and Yamuna are getting polluted day-by-day. Many factories discharge sewage effluents into these rivers. The load of pollution in these rivers also increases due to municipal sewage and many things thrown by people in the name of worship. The government has however taken some steps to save these rivers.

1. What are the values shown by people who throw wastes in rivers?
2. How could we help in decreasing pollution of rivers?
3. State some advantages of saving the river
4. State the action taken by the government to stop the pollution in these rivers.

Explain the efforts for the conservation of biodiversity at international level.

Why are colour blindness and thalassemia categorised as Mendelian disorders? Write the symptoms of these diseases seen in people suffering from them.

Jeremy went to a butcher's shop with his father and saw that the goats before slaughter were fed on grasses and was fascinated to see the sequence of organism through which the food passes. On seeing his fascination his father asked him the reason and he quickly explained him the concept of food chain.

1. Describe food chain.
2. Grass was eaten by goat which in turn is consumed by humans. Explain their relation.
3. Name different types of food chains.
4. What values are shown by Jeremy?

What will be the P/ R ratio of a climax community and a pioneer community. What explanation could you offer for the changes seen in P/ R ratio of a pioneer community and the climax community.

Write the name of any one water-borne disease. Explain the measures to prevent water-borne diseases.

Who revealed biochemical nature of the transforming principle? How was it done?

Explain the following with reason :