1.

What are the difficulties that youwould face in

classification of animals, if common fundamental
features are not taken into account?

Sol.

Common fundamental features help in grouping

animals in certain categories sub-categories. For
example, the common fundamental feature of all
the Arthropods is joined legs for locomotion. Higher
animals, like mammals too have joined but the
difference is the absence/ presence of muscles to
facilitate articulation.
Similarly, all birds have fore-limbs modified to assist
in flying. This gives us one clue to categorise a
particular animal among aves.
Had we not used fundamental features we could
not get a point to start with. Fundamental features
help us further pin point the classification and
identification.
2. If you are given a specimen, what are the steps
that you would follow to classify it?

Sol.

Steps to Follow for Classification:

1. Identify Levels of Organization. ldentify if it is
cellular level of organizationor tissue level of
organization.
2. Identify Body Symmetry. Find if the animal is
having a radial body symmetry or a bilateral body
symmetry.
3. Presence or Absence of Body Cavity. This will
give a clue if the animal belongs to acoelomata or
pseudocoelomata or coelomata.
Once these steps have been followed a fair idea can
be derived about animal. It can be inferred if the
animal is multicellular or unicellular. It can be known
if the animal isa chordate or a non-chordate.
3. How useful is the study of the nature of body
cavity and coelom in the classification of animals?
Sol.

The presence or absence of the body cavity gives a

clue about a particular animals position in
evolutionary ladde. The absence of coelom
indicates that the animal is yet to develop a
functionaldivision of labour to carry out various
activities.

This indicates towards a simplicityof activities

going on inside the body. The presence of coelom
paves the way for evolution of a more complex and
more efficient organ systenm for various activities.
4. Distinguish between intracellular and
extracellular digestion?
Sol.

In smaller animals the food comprises of mainly

basic molecules, like carbohydrates so need of
elaborate digestive system is not there. The same
cell is responsible for carrying out allthe basic
activities. The intracellular digestion is enough to
take care of the nutrition needs of the animal in this
case.

In animals with complicated systems the need for

variety of food components increases manifold. The
complexity of food substances necessitates a
complex digestive system. So major steps of
digestion take place outside the cell.
5. What is the difference between direct and
indirect development?
Sol.

Direct Development. In direct development the

young animal resembles an adult.
There is no intermediate stage.
Indirect Development. In indirect development there
is intermediate stage, like larval stage. For example,
frogs before being developed into adult pass
through a tadpole stage. This is the case of indirect
development.
6. What are the peculiar features that you find in
parasitic platyhelminthes?

Sol.

In parasitic platyhelminthes hooks and suckers are

present. Suckers help the parasite in sucking the
blood from the host.
7. What are the reasons that you can think of for
the arthropods to constitute the largest group of the
animal kingdom?
Sol.

Arthropods are the first phylum to have well

developedsystems to carry out different activities.
There is distinct system for respiration, locomotion
and reproduction. Their survival capacity is great
because of elaborate system. This has helped them
Survive in diverse conditions.

Theycan live in water, on land and in air. This can be

one of the reasons why arthropods are the largest
group among the animal kingdom. Another reason
is their early development compared to animals of
higher phylum.
8. Water vascular system is the characteristic of
which group of the following:
a. Echinodermata

b. Porifera

c. Ctenophora
d. Chordata

Sol. a)

Echinodermata

Echinodermata contain water vascular system that

help in nuttrition and respiration.
9. Allvertebrates are chordates but allchordates
are not vertebrates. Justify the statement.

Sol.

Allchordates have notochord present in some stage

of life. The difference between vertebrates and non
vertebrates is as follows: In vertebrates the
notochord is present in the embryonic stage. This is
replaced by a vertebral column during the adult
stages.
10. How important is the presence of air bladder in
Pisces?

Sol.

Presence of air-bladder in Pisces helps in buoyancy.

This means that members of pisces don't have to
keep on swimming to remain floating.
11. What are the modifications that are observed in
birds that help them fly?
Sol.

Following modifications in birds help them fly:

1.Pneumatic or hollow bones make for a lightweight
skeleton.
2. Fore-limbs are modified into wings to assist in
flight.
3. Excretion of urine and faeces is through single
opening facilitating weight reduction.
4. Aerodynamic body helps in flying.
12. Could the number of eggs or young ones
produced by an oviparous and viviparous mother be
equal? Why?
Sol.

Usually number of eggs produced by oviparous

mothers is greater than number of young ones
produced by viviparous mothers. The main reason
for this is the need of resources required for
development of the embryo. In oviparous the major
part of development of the embryo takes place
outside the uterus.

This makes lesser burden on the mother. On the

other hand in viviparous animals the development
takes place inside the uterus so lesser number of
young ones can be successfully incubated.

Moreover, once eggs are outside they are at risk of

getting eaten by some predator because of their
immobility,so need of more eggs is there to ensure
continuity of progeny.
13. Segmentation in the body is first observed in
which of the following:

a. Annelida

b. Platyhelminthes

c. Aschelminthes

d. Arthropoda

Sol. a)

Annelida

Annelida body is divided into small segments.

14. Match the folowing:

)Operculum (a) Ctenophora

(ii) Parapodia (b) Mollusca

(ii) Scales (c) Porifera

|(v) Comb plates(d) Reptilia

(V) Radula (e) Annelida

() Cyclostomata and
(vi) Hairs
Chondrichthyes

(vi)
(g) Mammalia
Choanocytes

(vii) Gill slits (h) Osteichthyes

Sol.

The correct order of match is ()-(h), (ii)-(e), (ii)-(d),

(iv)-(a), ()-(b),(vi)-(g), (vii)-(c), (vii)- ().
15. Prepare a list of some animals that are found
parasitic on human beings.
Sol.

Parasites on Human body

i. Ascaris
ii. Wucheraria
ii. Acylostoma
0v. Taenia
v. Fasciola