Three food chains are shown below:
  1. Grass\(\rightarrow\)Deer \(\rightarrow\) Tiger
  2. Tree \(\rightarrow\) Beetle \(\rightarrow\) Bacteria
  3. Flowering plant \(\rightarrow\) Butterfly \(\rightarrow\) Bird
They can be represented by the three pyramids of numbers P, Q and R below:

Write the correct combination that correctly matches food chains and pyramids.

Due to uncontrolled excessive hunting, the population of tigers in a forest has become zero.Discuss the long-term effects of this situation on the population of deer in that forest.

Decomposition is the process of breaking down of complex organic matter into inorganic substances. Different steps involved in the process of decomposition are fragmentation, leaching, catabolism, humification and mineralisation. Fragmentation is the breakdown of detritous (dead remains and faecal matter)with the help of detrivores e.g.earthworm.With reference to the above paragraph, answer the questions that follow.
(i) State the phylum and scientific name of earthworm.
(ii) The process of fragmentation involves the coordinated function of its digestive and excretory system.Mention the location of oesophagus, integumentary nephridia, typhlosole and gizzard in the earthworm.
(iii) Why does an earthworm die in sunlight?

Nutrients are essential for growth of producers, i.e. for the primary productivity of the ecosystem. The inorganic elements required by the plants present in the soil in the form of minerals are called mineral elements or mineral nutrients. Some of these mineral elements are nitrogen, sulphur, calcium, iron and manganese.State the deficiency symptoms of all elements mentioned above

(i) Define pioneer species.
(ii) Among bryophytes, lichens and fern, which one is a pioneer species in a xeric succession? And why?