ECOSYSTEMS
2010 MARCH
1. During a study tour teacher showed the
primary colonizers on the banks of the river ‘Nila’.
a. Identify the succession and justify your
answer.
b. List the different stages of the
identified succession. (3)
2. While learning trophic levels in
class-room, teacher asked you to explain ‘standing crop’ to Raman. Explain. (1)
2010 SAY
1. Pond is a self-sustainable unit. Some
organisms related to pond ecosystem is listed below:
Tadpole, fish, water, plants, kingfisher
a. Construct a food chain with the listed
organisms.
b. Explain trophic level.
c. Point out trophic level of each organism
in the constructed food chain.
d. Name interconnection of food chains in
nature. (4)
2011 MARCH
1.
Consider
pond as an ecosystem showing the number of individuals in the following
categories.
Carnivores- 2500, Producers- 15000,
Herbivores- 5000
a. Draw the pyramid of numbers in this
ecosystem.
b. Comment on the energy flow in the
ecosystem. (2)
2. The gradual change in the species
composition of a given area leading to the formation of climax community is
called ecological succession. In a rocky area,
a. What is the expected type of pioneer
species?
b. How this pioneer species leads to the
establishment of a stable climax community? (2)
2011 SAY
1.
Fill up
the blanks with appropriate terms in the given pyramid of trophic level: (1)
2. Kalyani wrote man, hen, earthworm,
mango-tree in her notebook. Arrange the terms in a food chain sequence. Explain
food chain and name the types of food chain.
(3)
2012 MARCH
1.
In a marine ecosystem, a population of phytoplankton
(150,000) supports a standing crop of fishes (40,000).
a.
Draw the pyramid of biomass and
b.
The pyramid of numbers in this ecosystem. (2)
2.
The gradual and fairly predictable change in the
species composition in an area is called ecological succession.
a.
Name the pioneer species in the primary succession
in water.
b.
Give the sequence of events and climax community in
the hydrarch succession. (2)
2012 SAY
1. Given number of individuals in a grass
land ecosystem.
Grasshopper – 1500 Grass – 5,842,000 Wolf – 28 Birds – 215
a. Draw a pyramid of numbers showing various
trophic levels.
b. Explain trophic level. (2)
2. Rate of biomass production is called
productivity and can be divided into GPP and NPP.
a. Define GPP and NPP. b. How can we relate GPP and NPP? (2)