Chapter-13 Organisms and Populations

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 antarctic fish                       _______________
x. An organism which can conform                                      _______________

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

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

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

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

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.

Discuss the various types of positive interactions between species.

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

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

List any four characters that are employed in human population census.

Define ‘zero population growth rate’. Draw a age pyramid for the same.

What is a tree line?

Give the scientific names of any two microorganisms inhabiting the
human intestine.

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.

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?

In a pond, we see plants which are free-floating; rooted–submerged;
rooted emergent; rooted with floating leaves. Write the type of plants
against each of them.
Plant Name Type
a. Hydrilla _____________
b. Typha _____________
c. Nymphaea _____________
d. Lemna _____________
e. Vallisnaria _____________

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

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

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

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

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

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

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?

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

Define ectoparasite and endoparasite and give suitable examples.

Give a suitable example for commensalism.

What is high altitude sickness? Write its symptoms.

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

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

What is diapause and its significance?

Define aestivation.

What is homeostasis?

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

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

What is Mycorrhiza?

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

What is commensalism?

What is the interaction between two species called?

Define stenohaline species.

Species that can tolerate wide range of salinity are called ______.

What are Eurythermic species?

Species that can tolerate narrow range of temperature are called ______.

Orchid flower, Ophrys co-evolves to maintain resembelance of its petal to female bee. Explain how and why does it do so?

What is altitude sickness? What its causes and symptoms? How does human body try to overcome altitude sickness?

Species facing competition might evolve mechanism that promotes co- existence rather than exclusion. Justify this statement in light of Gause’s competitive exclusion principle, citing suitable examples.

How will you measure population density in following cases? (i)        fish in a lake

(ii)   tiger census in a national park

(iii)  single huge banyan tree with large canopy.

Darwin showed that even a slow growing animal like elephant could reach enormous number in absence of checks. With the help of your understanding of growth models, explain when is this possible? Why is this notion unrealistic?

How does the shape of age pyramid reflect the growth status of a population?

Why do clown fish and sea anemone pair up? What is this relationship called?

What are the four ways through which the living organisms respond to abiotic factors?

Mention the attributes which a population has but not an individual organism.

List four features which enable the Xeric plants to survive in the desert conditions.

Differentiate between stenohaline and euryhaline organisms

What are the four levels of biological organisation with which ecology basically deals?

Write what do phytophagous insects feed on?

An organism has to overcome stressful condition for a limited period of time. Which strategies can it adopt to do so?

In biological control method, one living organism is used against another to check its uncontrolled growth. Which kind of population interaction is involved in this?

Calculate the death rate if 6 individuals in a laboratory population of 60 fruit flies died during a particular week

Define diapause. Which organisms exhibit it?

With  which  population  growth  model  is  the  Verhulst  Pearl  equation associated?

Fresh water animals are unable to survive for long in sea water. Give reason.

Which are the factor responsible for the wide variety of habitat formed within each biome?

Study the three representative figures of age of pyramid relating to human
population & answer the following question.

Why are predators “prudent in nature?

Mention any two ways in which organisms tide over unfavourable
conditions by suspending their activities.

Most living organisms cannot survive at temperature above 450c. How are
some microbes able to live in habitat with temperature exceeding 1000c.

What role do predators play in an ecosystem?

List any two factors which determine the nature of soil?

Name the mechanism employed by ophrys to get its flowers pollinated?

Write the equation for verhulst – poarl logistic growth of population.

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

What is Age pyramid? What are the different types of age pyramid?

Give an example to show that completely unrelated species can also
compete for same resources?

How is diapause different from Hibernation?

How do kangaroo rats live in the absence of water in North American
deserts?

Out of the two population growth models, which one is more realistic &
Why?

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

Define carrying capacity?

What are the two primary requirements of a parasite from host?

Why are calotropis plants not browsed by herbivores?

Name the type of interaction in which one species is harmed while other
is neither benefitted nor harmed?

Describe the logistic growth model of population along with a suitable
curve. Why is this curve more realistic?

Mutualism often involves co-evolution of mutualists. Describe taking
the example of animal plant (wasp-fig) relationship.

Mention the different defense mechanism to reduce the impact of
predation?

Name the bind of interaction present between the following :-
i) Indian Nightingale & crow
ii) Nodulated roots & rhizobium
iii) Plasmoduim & man
iv) Orchids & Mongo tree

Differentiate between Hibernation & aestivation?

How do desert lizards maintain a fairly constant body temperature?

What does J-shaped curve indicates?

Give one function of aerenchyma in aquatic plants?

“Cuckoo bird lays eggs in the nest of crow” which type of interaction is
shown in this relation?

Describe the exponential growth model of a diagram along with a curve?

Name & explain the bind of interaction in the following.
i) Algae & fungi in
ii) Head louse & humans
iii) Hermit crab & sea anemone

Describe the specific adaptations of hydrophytes with respect to roots,
stem & leaves?

What is migration? Why do animals show this phenomenon?

State Gauss’s competitive exclusion principle?

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

What is Allen’s rule?

Give an example of suspension?

Define homeostasis?

List the important characteristics of a population & Explain?

Describe the specific adaptation of xerophytes with respect to root
system, stem & leaves.

What is Brood parasitism? Give an example. What adaptation has evolved
in this phenomenon?

Give any two examples of defense mechanism in plants against
herbivory?

Lichens are considered good examples of obligate mutualisms”.
Comment?

Distinguish between ectotherms & Endotherms?

What type of interaction is shown by sparrows eating the seeds?

Name the type of interaction that is detrimental to both the interaction.

Why do leaves contains Sunken stomata?

List any three important characteristics of a population and explain

Select the statement which explains best parasitism.

(a) One organism is benefited.

(b) Both the organisms are benefited.

(c) One organism is benefited, other is not affected.

(d) One organism is benefited, other is affected.

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

Define the following terms and give one example for each:

(a) Commensalism

(b) Parasitism

(c) Camouflage

(d) Mutualism

(e) Interspecific competition

Define population and community.

Give an example for:

(a) An endothermic animal

(b) An ectothermic animal

(c) An organism of benthic zone

List the various abiotic environmental factors.

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.

Distinguish between the following:

(a) Hibernation and Aestivation

(b) Ectotherms and Endotherms

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

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

Name important defence mechanisms in plants against herbivory.

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

List the attributes that populations but not individuals possess.

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

Define phenotypic adaptation. Give one example.

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

How is diapause different from hibernation?