Biology

Organisms and Populations

Question:

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

Answer:

Yes, regional and local variations exist within each biome. Regional and local variations within each biome lead to the formation of a wide variety of habitats. On planet Earth, life exists not just in a few favourable habitats but even in extreme and harsh habitats-^scorching Rajasthan desert, perpetually rain-soaked Meghalaya forests, deep ocean trenches, torrential streams, permafrost polar regions, high mountain tops, boiling thermal springs, and stinking compost pits, to name a few. Even our intestine is a unique habitat for hundreds of species of microbes.

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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.

Comment on the following figures 1, 2 and 3:
A, B, C, D, G, P, Q, R, S are species
ncert-exemplar-problems-class-12-biology-organisms-and-populations-10

Q 4.

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

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.

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

Q 7.

Species that can tolerate narrow range of temperature are called

Q 8.

What is Mycorrhiza?

Q 9.

What is the interaction between two species called?

Q 10.

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.

Q 11.

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

Q 12.

Name important defence mechanisms in plants against herbivory.

Q 13.

Define stenohaline species.

Q 14.

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

Q 15.

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 16.

What are Eurythermic species?

Q 17.

Species that can tolerate wide range of salinity are called .

Q 18.

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 19.

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 20.

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 21.

Give a suitable example for commensalism.

Q 22.

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 23.

Discuss the various types of positive interactions between species.

Q 24.

What is high altitude sickness? Write its symptoms.

Q 25.

In an association of two animal species, one is a termite which feeds on wood and the other is a protozoan Trichonympha present in the gut of the termite. What type of association they establish?

Q 26.

An individual and a population has certain characteristics. Name these attributes with definitions.

Q 27.

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

Q 28.

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

Q 29.

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

Q 30.

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

Q 31.

Observe the set of 4 figures A, B, C and D, and answer the following questions: •
(i) Which one of the figures shows mutualism?
(ii) What kind of association is shown in D?
(iii) Name the organisms and the association in C.
(iv) What role is the insect performing in B?
ncert-exemplar-problems-class-12-biology-organisms-and-populations-9

Q 32.

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 33.

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

Q 34.

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 35.

Last the attributes that populations but not individuals possess.

Q 36.

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 37.

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

Q 38.

Categorise the following plants into hydrophytes, halophytes, mesophytes and xerophytes. Give reasons for your answers.
a. Salvinia b. Opuntia
c. Rhizophora d. Mangifera

Q 39.

Fill in the blanks:
ncert-exemplar-problems-class-12-biology-organisms-and-populations-7

Q 40.

List any three important characteristics of a population and explain.

Q 41.

What is commensalism?

Q 42.

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

Q 43.

Define aestivation.

Q 44.

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

Q 45.

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

Q 46.

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

Q 47.

Name the association in which one species produces poisonous substance or a change in environmental conditions that is harmful to another species.

Q 48.

What is diapause and its significance?

Q 49.

What are the organisms that feed on plant sap and other plant parts called?

Q 50.

Define ectoparasite and endoparasite, and give suitable examples.