Ecosystems — BIOLOGY STD 12 Science — Question

Draw and label the enlarged view of microsporangium of an Angiosperm. State the function of its innermost wall layer.

Explain the struggle for life in the context of Darwin.###According to Darwin, how many types of struggle for life are there in nature? Explain.

Differentiate between somaclones and somatic hybrids. Give one example of each.

A student on a school trip started sneezing and wheezing soon after reaching the hill station for no explained reasons. But, on return to the plains the symptoms disappeared. What is such a response called? How does the body produce it?

Write any four differences between bacteria and cyanobacteria.

A farmer harvests his crop and expresses his harvest in three different ways.

1. I have harvested 10 quintals of wheat.
2. I have harvested 10 quintals of wheat today in one acre of land.
3. I have harvested 10 quintals of wheat in one acre of land, 6 months after sowing.

Do the above statements mean one and the same thing. If your answer is yes, give reasons. And if your answer is ‘no’ explain the meaning of each expression.

How will an organism be benefitted, if it reproduces through spores?

Draw the sketches of a zoospore and a conidium. Mention two dissimilarities between them and at least one feature common to both structures.

Name the type of interaction seen in each of the following examples:

1. Ascaris worms living in the intestine of human.
2. Wasp pollinating fig inflorescence.
3. Clown fish living among the tentacles of sea-anemone.
4. Mycorrhizae living on the roots of higher plants.
5. Orchid growing on a branch of a mango tree.
6. Disappearance of smaller barnacles when Balanus dominated in the Coast of Scotland.

Name the main stages of translation.