Biology

Organisms and Populations

Question:

Give one example for each of the following:
(i) Eurythermal plant species ………………
(ii) A hot water spring organism ………………
(iii) An organism seen in deep ocean trenches ………………
(iv) An organism seen in compost pit ………………
(v) A parasitic angiosperm ………………
(vi) A stenothermal plant species ………………
(vii) Soil organism ………………
(viii) A benthic animal ………………
(ix) Antifreeze compound seen in antarcticfish ………………
(x) An organism which can conform ………………

Answer:

(i) Eurythermal plant species Red algae
(ii) A hot water spring organism Thermus aquaticus
(iii) An organism seen in deep ocean trenches ”Sea cucumbers
(iv) An organism seen in compost pitâ Earthworm
(v) A parasitic angiosperm—Cuscuta reflexa
(vi) A stenothermal plant species—Conifers
(vii) Soil organism—Earthworm
(viii) A benthic animal—Crabs, Sponges
(ix) Antifreeze compound seen in Antarctic fish—Antifreeze glycoproteins orAFGPs
(x) An organism which can conform—Frog

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Organisms and Populations

Q 1.

What is homeostasis?

Q 2.

Why do all the fresh water organisms have contractile vacuoles whereas , majority of marine organisms lack them?

Q 3.

What is high altitude sickness? Write its symptoms.

Q 4.

Define stenohaline species.

Q 5.

Lianas are vascular plants rooted in the ground and maintain erectness of their stem by making use of other trees for support. They do not maintain direct relation with those trees. Discuss the type of association the lianas have with the trees.

Q 6.

Give one example for each of the following types.
(a) Migratory animal (b) Camouflaged animal
(c) Predator animal (d) Biological control agent
(e) Phytophagous animal (f) Chemical defense agent

Q 7.

Give a suitable example for commensalism.

Q 8.

Species that can tolerate narrow range of temperature are called

Q 9.

Define zero population growth rate'. Draw an age pyramid for the same.

Q 10.

Define the following terms and give one example for each:
(a)Commensalism (b)Parasitism
(c)Camouflage (d)Mutualism
(e)Interspecific competition

Q 11.

Do you agree that regional and local variations exist within each.biome? Substantiate your answer with suitable example.

Q 12.

What is Mycorrhiza?

Q 13.

ncert-exemplar-problems-class-12-biology-organisms-and-populations-6
a. Label the three tiers 1, 2, 3 given in the above age pyramid.
b. What type of population growth is represented by the above age pyramid?

Q 14.

Define population and community.

Q 15.

An orchid plant is growing on the branch of mango tree. How do you describe this interaction between the orchid and the mango tree?

Q 16.

In a pond, we see plants which are free-floating; rooted-submerged; footed emergent; rooted with floating leaves. Write the type of plants against each of them.
ncert-exemplar-problems-class-12-biology-organisms-and-populations-5

Q 17.

What is commensalism?

Q 18.

What are Eurythermic species?

Q 19.

What would be the growth rate pattern, when the resources are unlimited?

Q 20.

Give the scientific names of any two micro organisms inhabiting the human intestine.

Q 21.

If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population?

Q 22.

Last the attributes that populations but not individuals possess.

Q 23.

Species that can tolerate wide range of salinity are called .

Q 24.

What is the interaction between two species called?

Q 25.

While living in and on the host species, the animal parasite has evolved certain adaptations. Describe these adaptations with examples.

Q 26.

Write a short note on
(a)Adaptations of desert plants and animals
(b)Adaptations of plants to water scarcity
(c)Behavioural adaptations in animals
(d)Importance of light to plants
(e)Effect of temperature or water scarcity and the adaptations of animals.

Q 27.

The following diagrams are the age pyramids of different populations. Comment on the status of these populations.
ncert-exemplar-problems-class-12-biology-organisms-and-populations-12

Q 28.

What is the ecological principle behind the biological control method of managing with pest insects?

Q 29.

Emergent land plants that can tolerate the salinities of the sea are called

Q 30.

Define ectoparasite and endoparasite, and give suitable examples.

Q 31.

Why are coral reefs not found in the regions from. West Bengal to Andhra Pradesh but are found in Tamil Nadu and on the east coast of India?

Q 32.

Why do high altitude areas have brighter sunlight and lower temperatures as compared to the plains?

Q 33.

Define aestivation.

Q 34.

What is brood parasitism? Explain with the help of an example.

Q 35.

Why do submerged plants receive weaker illumination than exposed floating plants in a lake?

Q 36.

A population of Paramoecium caudatum was grown in a culture medium. After 5 days the culture medium became pvercrowded with Paramoecium and had depleted nutrients. What will happen to the population and what type of growth curve will the population attain? Draw the growth curve.

Q 37.

Name important defence mechanisms in plants against herbivory.

Q 38.

Comment on the growth curve given below.
ncert-exemplar-problems-class-12-biology-organisms-and-populations-13

Q 39.

Does light factor affect the distribution of organisms? Write a brief note giving suitable examples of either plants or animals.

Q 40.

With the help of suitable diagram describe the . ; logistic population growth curve.

Q 41.

In an aquarium two herbivorous species of fish are living together and feeding on phytoplanktons. As per the Gause's Principle, one of the species is to be eliminated in due course of time, but both are surviving well in the aquarium. Give possible reasons.

Q 42.

Which element is responsible for causing soil salinity? At what concentration does the soil become saline?

Q 43.

Define phenotypic adaptation. Give one example.

Q 44.

Most living organisms cannot survive at temperature above 45 °C. How are some microbes able to live in habitats with temperatures exceeding 100 °C?

Q 45.

List the various abiotic environmental factors.

Q 46.

Give an example for:
(a)An endothermic animal
(b)An ectothermic animal
(c)An organism of benthic zone

Q 47.

If a fresh water fish is placed in an aquarium containing sea water, will the fish be able to survive? Explain giving reasons.

Q 48.

Define heliophytes and sciophytes. Name a plant from your locality that is either heliophyte or sciophyte.

Q 49.

If a marine fish is placed in a fresh water aquarium, will the fish be able to survive? Why or why not?

Q 50.

In a sea shore, the benthic animals live in sandy, muddy and rocky substrata
and accordingly developed the following adaptations.
a. Burrowing  
b. Building cubes
c. Holdfasts/peduncle
Find the suitable substratum against each adaptation.