Chapter 9: Diversity among animals

Short Questions and Answers.

Non- reasoning.

Q1: Define the following

ANSWER: Parazoa
Organisms that lack true tissues are termed parazoa. E.g Sponges
Eumatazoa
Organisms that have tissues organized into organs (in lower groups) and organs into organ
systems (in higher forms) are called eumatazoa. E.g. Annelida, Arthropoda & Chordata.

Q2:What are diploblastic and triploblastic animals?

Triploblastic Animals.
Animals with three gem layers during development are called triploblastic animals. These
germ layers are:
ectoderm, mesoderm and endoderm. Such animals have organ and system levels of
organization
Example: Platyhelminthes to chordata.
Diploblastic Animals.
Some animals have only two germ layers during the development stage. These germ layers
are
Ectoderm and endoderm . Such animals have the tissue level of organization.
Example: Cnidarians.

Q3: Write a short note on symmetry

ANSWER: SYMMETRY
Symmetry means the overall shape of the body, that how the body parts are arranged
around the central axis.
. Asymmetrical animals.
The simplest animals have many representatives. whose bodies are irregular and variable in
shape called asymmetrical. E.g., sponges and snails.
Symmetrical animals
Eumatazoans are divided into two major groups based on body symmetry.
Bilateral symmetry
Bilateral symmetry is defined as body symmetry where the body can be divided into two
equal halves by only one plane is called bilateral symmetry and animals having bilateral
symmetry are called bilateral symmetrical animals. These animals have not only a dorsal and
ventral side but also an anterior and posterior end and left and right side. E.g.
platyhelminthese & Chordata.
Radial symmetry
Organisms being cut in two equal halves by any plane or axis are known as radial
symmetrical animals and this phenomenon is known as radial symmetry. A radial animal has
a top or bottom, or an oral and aboral side but no head and rear end and no left and right
side.
E.g: Cnidarians
Q4: Write a note on coelom.
ANSWER: COELOM
The coelom is the main body cavity that resides in the internal organs. It is a fluid-filled
cavity. A true coelom is that which is completely lined with mesoderm, internally as well as
externally.
Types of Coelom
There are three types of animals based on Coelom.
Acoelomate
Pseudocoelomates
Coelomates
Acoelomate
Simple animals such as flatworms(Platyhelminthes) lack any internal space or coelom
between their body wall and their gut and are called acoelomates.
E.g., flatworms (planaria).
Pseudocoelomates
Animals such as roundworms (Aschelminthes) have a body cavity called pseudocoelom.
Therefore they are called pseudocoelomates. Pseudocoelom is a false coelom because it is
not completely lined with mesoderm.it is only beneath the ectoderm but not around the
gut.
E.g,Round worms(aschelminthes).
Coelomates
Coelomates animals have a true body cavity or coelom that is completely lined with
mesoderm internally as well as externally.
E.g, Phylum annelids to chordates.

Q:6 Define protostoms and deuterostomes animals.

Protostomes
protostomes are the animals in which blastopore develops into a mouth during their
embryonic development.
E.g., Annelids, Molluscs, and Arthropods.
Deuterostomes
When the blastopore develops into an anus and the second opening becomes the mouth
during embryonic development• These animals are called deuterostomes.
E.g,Echinodermates, hemichordates and chordate.
Q7: Write functions of the following & What are the different types of cells present in
porifers?
ANSWER: Ostia
Pores in the body of members of phylum Porifera through which water is drawn into the
body.
Osculum
The osculum functions as an exit for the water to flow out from the body of a sponge.
Pinacocytes
The outer layer of sponges is made up of flattened epithelial cells known as pinacocytes.
Choanocytes
The inner layer of sponges is made up of flagellated cells called collar or choanocytes.
Amoebocytes
Amoebocytes form eggs and sperm during sexual reproduction.
Q11:Define polymorphism regarding Phylum Cnidaria.
Polymorphism
The phenomenon in which an organism has more than one distinctive body form or
physiological structure during its life is called polymorphism.
Members of phylum Cnidaria have 2 distinct body forms,
Polyps
Medusa
Polyps
Polyps are cylindrical with mouth and tentacles upward.
Medusa
Medusa is umbrella-shaped, whose tentacles are downward.

Q12: Write evolutionary adaptations of phylum Porifera.

ANSWER: BOOK PAGE NO 196

Q13: Write general characters of phylum Platyhelminthes.

ANSWER: GENERAL CHARACTERS OF PHYLUM PLATYHELMINTHES
BODY TYPE
They are acoelomate, triploblastic animals with organs and organ systems.
SYMMETRY
They are bilaterally symmetrical.
BODY STRUCTURE
Eye spots
Some flatworms have a head with a pair of eye spots that detect light.
Locomotion
free-living flatworms move with the help of cilia present on the ventral epidermis.
Reproduction
Flatworms can reproduce by both asexual and sexual methods. Free-living form reproduces
asexually through regeneration. All forms can reproduce sexually and most are
hermaphrodite (monoecious).

Q14: What is the use of leeches in medicinal purposes?

ANSWER: Leeches have been used for medicinal purposes for a long time. Back then it was
believed that leeching would get rid of the “Bad Blood” that caused diseases because
leeches are ectoparasites and suck the blood.

Q15: write evolutionary adaptations of the following

Phylum Cnidaria
Book page no 197
Phylum Platyhelminthes
Book page no 198 and 199
Phylum ascehelminthes
Book page no 199 and 200
Phylum Echinodermata
Book page no 204

Q27: Write the economic importance of arthropods.

Arthropods are of great economic importance,
The insects help the plants in pollination.
They act as predators of plant pests.
They act like vectors in the transmission of bacteria and viruses
Arthropods are an important source of food for many animals and carnivores plants.
Seafood other than fish or molluscs is generally arthropods.

Q18:What are the four main features of chordates?

FEATURES OF CHORDATES
The four main features of phylum Chordata which all members possess at different stages
are:
Notochord
Nerve cord
Gill slits
Post anal tail
Notochord:
It is a flexible rod that extends the length of the body and provides an attachment site for
muscles.
Nerve cord:
Lying dorsal to the digestive tract, this hollow neural structure develops a bulging at its
anterior end that becomes a brain.
Gill slits:
Gill slits are located in the pharynx, these may form functional respiratory openings or may
appear only as grooves during an early stage of development.
Post anal tail:
Most chordates have a tail extending posteriorly to the anus.

Q20: What are the major classes of vertebrates?

ANSWER: Vertebrates are classified into seven major classes
Class pieces (fishes)
Class Amphibia (living in both, water and land)
Class Reptilia (To crawl and creep)
Class Aves (Birds)
Class Mammalia

Q21: Differentiate btw vertebrate and invertebrate chordates.

Invertebrate chordates Vertebrates
Invertebrate chordates lack Vertebrates have large
a head. heads.

They have notochord in They have notochord only

every stage of life. during their

In adults, notochord is embryonic stages.

present in head to tail In adults, the notochord is
throughout life. replaced by the vertebral
column.
 They have simple brain and They have complex brain
sensory structures. and sensory structures.
They do not have Appendages are present.
appendages.

Example urochordates & Examples of amphibians,

cephalochordates. reptiles & mammals

Q22: Difference btw cartilaginous fish & bony fish.

Cartilaginous(Chondrichthyes) Bony(Osteichthyes)
Fishes Fishes
The skeleton of cartilaginous fish The skeleton of bony fishes is
is made up of cells called made up of cells called
chondrocytes. osteocytes.
Their skeleton is soft & flexible Their skeleton is hard.
An enormous number of tiny The exoskeleton is made up of
sharp, enamel-coated dentiles tiny plates which are called
called placoid scales. cycloid scales.
Their tail fin is heteroceral. Their tail fin is homocercal.
Gills are not covered by the Gills are covered by operculum.
operculum. Example Flying fish and globefish
Example Dog fish.

Q28: Four characters of reptilia

Tough skin
Reptiles contain tough, scaly skin that resists water loss and protects the body.
Fertilization
Fertilization in reptiles is internal.
Amniotic egg
Eggs of reptiles have a protective covering called amnion.
Heart
Reptiles have three-chambered hearts, allowing some better separation of oxygenated and
deoxygenated blood.

Q24: Write a short note on class aves.

ANSWER: CLASS AVES
A bird can be defined as feather feather-covered bipedal flying vertebrate possessing wings.
Characteristics of birds
Body temperature
Birds regulate their body temperature by physiological and behavioral mechanisms,
maintaining a temperature that is usually higher than that of their surroundings.
Metabolic rate
These animals have a high metabolic rate that increases their energy demand and requires
oxygen for tissues.
Heart
A chambered heart keeps oxygenated blood separated from deoxygenated blood.
Respiratory system
The respiratory system of birds is supplemented by air sacs that supply oxygenated air to the
lungs.
Wings
Forelimbs are modified into wings.
Fertilization
Fertilization is internal and eggs are amniotic.

Q25: Write the imp character of class mammalia.

Metabolism
Mammals have an active metabolism.
Endotherms
They are endotherms.
Respiratory and circulatory system
Efficient respiratory and circulatory systems having a four-chambered heart support a high
metabolic rate.
Diaphragm
A sheet of muscle called the diaphragm helps to ventilate the lungs.
Metabolic heat
Hairs and a layer of fat under the skin help the body to retain metabolic heat.
Q26: differentiate btw running bird and flying bird.OR dif btw ratitae and carinatae.
Ratitae(Running Carinatae(flying)

1Ratitae are running Carinatae are flying

birds having heavy birds having light body
body weight. weight.
They have rudimentary They have well-
and vestigial wings. developed wings for
They have a flat flight.
sternum without a keel. Their sternum is
Examples are ostrich, provided with a crest-
kiwi penguin, etc like keel.
Examples are pigeons,
crows, and parrots, etc.

Q28: Four characters of reptilia

Tough skin
Reptiles contain tough, scaly skin that resists water loss and protects the body.
Fertilization
Fertilization in reptiles is internal.
Amniotic egg
Eggs of reptiles have a protective covering called amnion.
Heart
Reptiles have three-chambered hearts, allowing some better separation of oxygenated and
deoxygenated blood.
Reasoning questions

Q9: Why diploblastic animals are different from the triploblastic animals?
ANSWER: Diploblastic animals are different from triploblastic animals because diploblastic
animals have two germ layers i.e, ectoderm and endoderm, for example, jellyfish whereas
triploblastic animals have three germ layers i.e, ectoderm, mesoderm, and endoderm for
example Ascaris.
Q:5 Why protostomes are named so?
Protostomes are named so, because in protostomes, during embryonic development,
blastopore develops into the mouth before the anus formation.
protostomia is a Greek word that means first mouth.
Eg: Annelids, Molluscs, and arthropods.
Q8: How animals are classified?
ANSWER: CRITERIA OF ANIMAL'S CLASSIFICATION
The classification or grouping of animals is called taxonomy or systematics. It is carried out
primarily based on their evolutionary relationships. Clues to these relationships are found in
Comparative morphology
Internal architecture
Which includes,
Presence and absence of tissues
Number of tissue layers
Symmetry and the embryological development pattern of their coelom and blastopore

Q10: Why are sponges placed in the animal kingdom, when it lacks tissue organization?
ANSWER: Sponges are placed in the animal kingdom because sponges have a Cellular grade
of organization. They do not possess any structure or organs instead sponges have cells of
various types that are responsible for body functions. For example, choanocytes help the
organisms to filter food particles.

Q17: Why flatworms are named so?

ANSWER: Flatworms are so named because their bodies are thin between the Dorsal and
ventral surfaces. Their dorsoventrally flattened bodies are relatively simple and
unsegmented. They range in size from nearly microscopic free living to 20m long tapeworms.
For example Planaria and liver fluke.

Q16:Why oyster are ambisexual?

ANSWER: The oyster is usually bisexual. Because it begins life as a male and then becomes a
female. it may go back and forth many times.

Q23: Why echinoderms are placed in bilateria when adults are radial symmetrical?
ANSWER: They are radially symmetrical as an adult, but as their larva is a free swimming
filter feeder with bilateral symmetry that's why echinoderms are placed in bilateria. for
example starfish and sea urchins.
Q19: Why birds can fly while other reptiles can not?
Birds can fly but other reptiles can not because birds have air sacs with their lungs and other
reptiles don't have air sacs moreover, birds have wings that are highly developed their
sternum is provided with crest-like keel and they have developed pectoral flight muscles
while reptiles lack all of these characters.

Q29: Why can a kiwi not fly Why kiwi not fly but an owl can? Why does an eagle fly and a
penguin not?
Kiwis/penguins can't fly because of their heavy weight and their wings are vestigial. similarly,
kiwis/penguins have a flat sternum without a keel and accordingly, their flight muscles are
poorly developed. On the other hand owls/eagles have sternum with a kneel and have well-
developed flight muscles.

Long questions and answers

Q30: Write general characters, evolutionary adaptations, and economic importance of
phylum Annelida.
ANSWER: General characters of Phylum Annelida
Common name
Annelids are commonly called segmented worms.
Habitat
they live on land. in moist soil, freshwater, or in the sea.
Body Type
They are all triploblastic coelomate and protostomes with an organ system level of
organization.
Symmetry
They are bilaterally symmetrical.
Locomotory organs
Chitinous chaetae also called setae with or without parapodia are usually present in most of
annelids and help in locomotion.
Reproduction
Reproduction is usually sexual, most annelids are hermaphrodites, and in a few, sexes are
separate, developing through trochophore larvae.
Examples
Common Annelids: Earthworms, Neries and Leech.
Evolutionary adaptations of phylum Annelida
Digestion: Tubular digestive system with both mouth and anus, complete system.
Respiration: The respiratory system is not found, diffusion is sufficient for gas exchange.
Transport: Closed-type circulatory system with blood confined to the. Heart and blood
vessels.
Excretion: Excretory organs are nephridia which are found in most segments.
Nervous system: Nervous system consists of simple ganglionic brain in the head
Economic importance.
Earthworms help the farmer by continuously plowing the soil and adding nitrogenous waste
into it thus making the soil fertile.

Q31: Write general characters of phylum arthropods and their evolutionary adaptations.
ANSWER: General characters of phylum Arthropoda
Habitat
They are found everywhere on earth wherever life is possible even in the oil wells.
Symmetry
They are bilaterally symmetrical.
body type
They are triploblastic coelomates and protostomes.
The segmented
body is divided into the head thorax and abdomen.
Exoskeleton
the body of arthropods is completely covered with a cuticle and exoskeleton made up of
protein and chitin.
Reproduction
Sexes are usually separate and metamorphosis is common.
Examples
honey bee scorpion mosquito.
Evolutionary adaptations of phylum Arthropoda
Digestion: Alimentary canal is Well developed with the mouth and anus. The mouth is
assisted by jaws, and the digestive system is complete.
Respiration: Arthropod's efficient gas exchange is accomplished by gills in aquatic forms
such as crustaceans, tracheae, and terrestrial forms. By either book- lungs in
Transport: Arthropods have a well-developed circulatory system, and blood not only travels
through vessels but also empties into the hemocoel, where it bathes the internal organs
directly, and this arrangement is known as an open-type circulatory system.
Excretion: Excretory organs are mostly malpighian tubules. They remove nitrogenous waste
by osmoregulation.
Nervous system: Arthropod's nervous system is similar in plan to that of annelids but more
complex. It consists of a brain composed of fused ganglia in the head, connected to a series
of ganglia running down the length of the body and linked by a ventral nerve cord.

Q32: Write general characters of phylum mollusca with their evolutionary adaptations.
ANSWER: General characters of phylum Mollusca
Habitat
All molluscs mostly live in aquatic regions or moist soil.
Body type
All the Molluscs are triploblastic coelomates with organ system level of body organization.
Symmetry
They are bilaterally symmetrical.
Body plan
All molluscs have a Similar body plan with three main parts
Muscular foot
Visceral mass
A mantle
Muscular foot
These are usually used for movement.
Visceral mass
It contains most of the internal organs.
Mantle
Mantle, a fold of tissue that wraps over the visceral mass and secretes a shell.
Food habitat
Many molluscs feed using a strap-like rasping organ called a radula to scrap food.
Reproduction
Reproduction is always sexual, some species have separate sexes and others are
hermaphrodites.
Example
Unio, pearl oyster, and Octopus
Evolutionary adaptations of phylum mollusca
Digestion: Digestive system is straight with mouth and anus.
Respiration: Exchange of gases in aquatic forms with gills and simple lungs in terrestrial
form.
Transport: Open-type circulatory system in which blood directly bathes the organs in a
hemocoel.
Excretion: well-developed excretory system using tubular nephridia.
Nervous system: Nervous system consists of ganglia connected by nerves, but many more of
the ganglia are concentrated in the brain.
Economic importance of mollusca:
A variety of molluscs called shellfish, together with crustaceans are still an important source
of food. Their shells are decorative,

Q33: Define class mammalia with its characters and sub-classes.

Metabolism
Mammals have an active metabolism.
Endotherms
They are endotherms.
Respiratory and circulatory system
Efficient respiratory and circulatory systems having a four-chambered heart support a high
metabolic rate.
Diaphragm
A sheet of muscle called the diaphragm helps to ventilate the lungs.
Metabolic heat
Hairs and a layer of fat under the skin help the body to retain metabolic heat.
Development of embryo
(except the egg-laying monotremes, such as the platypus and spiny anteater mammalian
embryos develop in the uterus.
Sub-classes
Class mammalia is divided into three subclasses Prototheria,
Metatheria and
Eutheria,
Sub-class Prototerhia (egg-laying mammals)
Egg laying mammals
They are the only living mammals that lay eggs.
Structure of egg
The egg of prototheria is like a reptilian, in structure and development.
Nourishment of embryo
contains enough yolk to nourish the developing embryo.
Example
Spiny ant eaters and platypus.
Sub-classes Metatheria
They are called pouched mammals.
Development.
A marsupial mammal(pouch mammal) is born very early in its development and completes
its embryonic development while nursing.
Marsupium
In most species, the nursing young are held within a maternal pouch called a marsupium.
example
Kangaroos (Fig: 9.31-a), Koalas (Fig: 9.31-b), and Opossums (Fig 9.31-c) are examples of
pouch mammals
Sub-class Eutheria (Placental mammals)
Period of pregnancy
Eutherian mammals have a longer period of pregnancy.
Embryonic development.
Young eutherians complete their embryonic development within the uterus, joined to the
mother by the placenta.
Placenta
The embryo receives oxygen and food from the mother's circulation and discharges the
wastes into her blood through the placenta.
Common eutherian mammals are Hedgehogs, rabbits & humans.