NCERT Solutions for Class 11 Science Biology Chapter 4 - Animal Kingdom

Answer:

Answer:

Interstitial cells are present between two epitheliomuscular layers and comprise about 80% of total Hydra cells. They are reserve cells that can differentiate into any type of cells. 

Hence, the correct answer is option b

Answer:

Answer:

Answer:

Birds and mammals are highly evolved organisms, having a common feature as warm-blooded, which means they can maintain a constant body temperature and do not need to rely on an external heat source to stay warm.

Hence, the correct answer is option d.

Answer:

Monkey, Chimpanzee, Man belong to a single taxonomic group such as order: Primates and class: Mammalia.  They are characterized by their advanced cognitive development and abilities, grasping hands and feet, and forward-facing eyes, along with other characteristics.

Hence, the correct answer is option c.

Answer:

Fasciola hepatica, also known as the common liver fluke or sheep liver fluke, is a parasite belonging to class Trematoda, and phylum Platyhelminthes. They have no body cavity i.e., acoelomate.

Hence, the correct answer is option c.

Answer:

The Prawns have green gland or antennal gland as excretory organ, which are found in pairs. They have one pair of green glands, located at the base of each antenna.

Hence, the correct answer is option A.

Answer:

Platypus and Echidna belongs to the subclass Prototheria that contains the egg-laying mammals, which are the most ancestral forms in the class Mammalia. Prototherians can be traced back to a lineage that began from reptile-like creatures, that  can be grouped into two families and a single order, the Monotremata. 

Hence, the correct answer is option a.

Answer:

Answer:

Correct match:

Answer:

Answer:

Correct match: 
 

Answer:

Phylum Echinodermata are exclusively marine animals, the larval forms of which show bilateral symmetry and adult forms show radial symmetry. e.g. Sea urchin, Star fish etc.
 

Answer:

Pneumatic bones are hollow and light weight, so it keep the body of aves light and hence help in flight. Air sacs help in respiration and buoyancy. It also aid as cooling devices and regulate body temperature.

Answer:

It is the phenomenon in which, the alternation of a sexual phase and an asexual phase in the life cycle of an organism occurs. These two phases, or generations, are different  morphologically, and sometimes chromosomally.

e.g. Obelia of Phylum Cnidaria exhibit metagenesis,where two basic body forms called polyp and medusa exist.

Answer:

The important functions of feathers  are:

• They provide  protection and insulation to birds.
• The feathers in the wings and tail play important role in controlling flight. 

Answer:

Class Cyclostomata, also called jawless fish possess sucking and circular mouths without jaws, hence they are also called Agnathans.
e.g., Lampreys, Hagfish.

Answer:

An animal possessing placoid scales- Trygon, Pristis
An animal possessing cycloid scales- Catla, Labeo 

Answer:

• Body is covered by dry and cornified skin.
• Internal fertillisation and Cleidoic eggs.

Answer:

The arthropods are the animals with chitinous exoskeleton.e.g. Cockroach 
The molluscans are the animals whose body is covered by a calcareous shell.e.g. Snails

Answer:

Radula is a file like rasping organ, present in most of the molluscs. It is a minutely toothed structure which is typically used for scraping or cutting food before the food enters the oesophagus.

Answer:

Bioluminescence is a form of chemiluminescence that involves the production of light energy within an organism's body. It occurs widely in most of the marine invertebrates that belong to the phylum Ctenophora.

For example-  Ctenoplana, Pleurobrachia, etc.

Answer:

a. Cold blooded animal- Rana tigrina
b. Warm-blooded animal- Homo sapiens
c. Animal possessing dry and cornified skin- Caiman crocodilus
d. Dioecious animal - Ascaris lumbricoides

Answer:

Answer:

a. Round worm- Ascaris lumbricoides
b. Fish possessing poison sting- Trygon
c. A limbless reptile / amphibian-  Ichthyophis
d. An oviparous mammal- Ornithorhynchus anatinus

Answer:

a.  Blood-filled cavity in arthropods - Haemocoel
b. Free-floating form of cnidaria - Medusa
c. Stinging organ of jellyfishes - Nematocyst
d. Lateral appendages in aquatic annelids - Parapodia

Answer:

Answer:

a.

Answer:

Answer:

The hearts show the evolution of the heart from a two-chambered heart in fish to a three-chambered in frogs to a four-chambered in mammals.

 Two chambered heart- One auricle and one ventricle- Class Chondrichthyes and Class Osteichthyes
Three chambered heart- Two auricles and one ventricle- Class Amphibia and Class Reptilia (except crocodiles)
Four-chambered heart- Two auricles and two ventricles- Class Aves and Class Mammalia

Answer:

Answer:

Answer:

1. Presence of adhesive organs like hooks and suckers for attachement to the host body.
2. Absence of digestive system.
3. Presence of high reproducing capacity.
4. Generally hermaphrodite.
5. Loss of sense organ

Answer:

a. Pila- v. Presence of shell
b. Cockroach- i. Jointed appendages
c. Asterias- iii. Water vascular system
d. Torpedo- iv. Electric organ
e. Parrot- ii.  Perching
f. Dog Fish- vi. Placoid scales

Answer:

a. 

Answer:

a. Chondrichthyes have cartilaginous endoskeleton having a ventrally located mouth. They have 5-6 pairs of gills without operculum. They show a streamlined body with a heterocercal tail. They are jawed fish that lack a swim bladder. They have leathery skin with placoid scales. They show internal fertilization with the help of claspers on males. e.g., Shark, Stingrays.

Osteichthyes have a bony endoskeleton having a terminally located mouth. They have 4 pairs of gills covered by the operculum. They show a streamlined body with a homocercal tail. They are jawed fish that shows the presence of swim bladder. They have cycloid or ctenoid scales. They lay eggs outside their body which are later externally fertilized by male sperm in the water. e.g., Rohu, Catla.

b. Both Urochordates and Cephalochordates belong to Protochordates. Both are marine and filter feeders. Urochordata, are also called tunicates because their body is covered by tunicin, a cellulose like substance. They show notochord in larval stage, in larval tail which disappear in adults, hence shows retrogressive metamorphosis.e.g., Herdmania, Salpa.

Cephalochordates show presence of notochord throughout their life, from head to tail region. e.g.,Amphioxus.
 

Answer:

a. The two similarities between aves and mammals are

• Both are homeothermic
• Both have four chambered heart

• Both are poilikothermic
• Both can respire through lungs.

• Both are oviparous.
• Both are poikilothermic.

Answer:

a. A limbless animal- 

Description

Answer:

a. A viviparous animal- Panthera leo
b. A fish possessing a poison sting- Trygon (Sting ray)
c. A fish possessing an electric organ- Torpedo (Electric ray)
d. An organ, which regulates buoyancy- Air Bladder
e. Animal, which exhibits alternation of generation-  Obelia (Sea-Fur)
f. Oviparous animal with mammary gland- Ornithorhynchus (Duck-billed Platypus)

Answer:

a. Balanoglossus- vi. Probosci's gland
b. Leech- Nephridia
c. Locust- Malpighian tubule
d. Liver fluke- Flame cells
e. Sea urchin- Absent
f. Pila- Metanephridia
 

Answer:

• They are triploblastic, bilaterally symmetrical, eucoelomate with organ system level of organisation.
• They show the presence of  dorsal, hollow nerve cord.
• They have pharyngeal gill slits, ventral heart and post anal tail.

Answer:

The relationship between germinal layers and the formation of body cavity in case of coelomate, acoelomates and pseudocoelomates are

• Coelomates-There are three germ layers in coelomate- ectoderm,mesoderm and endoderm, having true coelom which arises as a  cavity in embryonic mesoderm. Here, body cavity is lined by mesoderm. e.g., annelida, mollusca, chordates etc.
• Acoelomates-There are two germ layers in acoelomate- ectoderm and endoderm, having no body cavity. e.g., platyhelminthes.
• Pseudocoelomates- There are three germ layers in coelomate- ectoderm,mesoderm and endoderm, but the mesoderm is present as scattered pouches between ectoderm and endoderm.The body cavity is false as it is derived from blastocoel of the embryo.e.g., aschelminthes.

Answer:

Class Amphibia-

• Habitat-They are adapted for both water and land.
• External features- The body is divided into head and trunk. Tail is present in some cases. They have a pair of nostril,eye and tympanum which represents ear. Their skin is moist and glandular. They show sexual dimorphism. They are first true tetrapods with four limbs. They are ectothermic. e.g., Rana tigrina, Ambystoma, Bufo.

• Habitat- They are exclusively terrestrial,the first vertebrate to live on land. 
• External features- The body is divided into head,trunk and tail(mostly). They have highly keratinised skin with scales. They have a  pair of eyes. They have a keen sense of smell. Middle ear and internal ear  are well developed. They lay hard shelled eggs. They are ectothermic or cold-blooded, so they go for basking in the sun to raise their body temperature, and retreat to shady areas when they get hot which lowers their body temperature.e.g., Sphenodon,Hemidactylus, Draco, Ophiosaurus.

Answer:

Mammals are most adapted among the vertebrates because

• They are homeotherms that are adapted for aquatic, arboreal, and aerial life.
• The skin of the mammals is unique having a sweat gland, sebaceous gland, and possessing hair.
• RBCs without nucleus except for camel
• Four chambered heart
• Presence of external ear, three ear ossicles in middle ear and coiled spring like cochlea in internal ear
• Two pairs of limbs for walking, climbing, swimming, flying, running or burrowing
• Dioecious body with internal fertilisation and development
• Direct development, formation of placenta and viviparity