NCERT Solutions for Class 11 Biology Chapter 4
NCERT Solutions for Class 11 Biology Chapter 4 Animal Kingdom to Study online as well as available to download in PDF format free for new academic session 2020-2021. Download NCERT Solutions based on latest and updated NCERT Books for CBSE courses 2020-21.Join the Discussion Forum to ask questions or reply the others.
NCERT Solutions for Class 11 Biology Chapter 4
|Chapter 4:||Animal Kingdom|
Class 11 Biology Chapter 4 Solutions in English
NCERT Solutions for Class 11 Biology Chapter 4 is given below to download in PDF format free for new academic session 2020-21. Download Offline Apps based on updated NCERT Solutions 2020-21 following the latest CBSE Syllabus 2020-21. NCERT Books are also given to download in PDF form for class 11 all subjects. Ask your questions via Discussion Forum to discuss with others.
Important Terms related to Chapter 4
Bilateral symmetry: Only one plane can divide the organism into two identical left and right halves e.g., Annelids and Arthropods.
1. Coelom (Body cavity which is lined by mesoderm)
2. Coelomates: Have coelom e.g., Annelids, Arthropods, molluscs, Echinoderms, Chordates etc.
3. Pseudocoelomates: No true coelem as mesoderm is present in scattered pouches between ectoderm and endoderm. e.,g., Aschelminthes.
4. Acoelomates: Body cavity is absent e.g., Platyhelminthes.
Important Terms on Animal Kingdom
1. Asymmetrical: Cannot be divided into equal halves through median plane e.g., Sponges.
Radial symmetry: Any plane passing through central axis can divide organism into identical halves. e.g., coelentrates,Ctenophores and echinoderms.
2. Metamerism: If body is externally and internally divided into segments (metameres) with serial repetition of atleast some organs, then phenomenon is called metamerism e.g., Earthworm.
3. Pseudometamerism: Found in tapeworm. The proglottids (segments of tapeworm) budded off from neck not emryonic in origin.
4. Notochord: Rod-like structure formed during embryonic development on t he dorsal side. It is mesodermally derived e.g., Chordates. Non-chordates do not have notochord .e.g., porifera to echinoderms.
1. Also called as sea walnuts or comb jellies.
2. Are exclusively marine, radially symmetrical.
3. Have tissue level organisation, are diploblastic.
4. Digestion both extra and intracellular.
5. Body has eight external rows of ciliated comb plates for locomotion.
6. Show Bioluminescence (Property of living organisms to emit light).
7. Hermaphrodite (sexes are not separate).
8. Only sexual reproduction occurs. Exernal fertilization. Indirect development. e.g., Ctenoplana, Pleurobrachia.
1. Are aquatic or terrestrial, free-living or parasitic.
2. Are bilaterally symmetrical, triploblastic, organ-system level of organisation and metamerically segmented body.
3. Are coelomate animals.
4. Have longitudinal and circular muscles for locomation.
5. Have closed circulatory system.
6. Nereis (dioecious and aquatic annelid) has lateral appendages called parapodia for swimming.
7. Have nephridia for osmoregulation and excretion.
8. Neural system consists of paired gangila connected by lateral nerves to a double ventral nerve cord.
9. Reproduction is sexual. e.g., Earthworm (Pheretima) and Leech (Hirudinaria) which are hermaph rodites (i.e., monoecious).
Important Questions on 11th Biology Chapter 4
If we consider specific characteristics, then each organism will be placed in a separate group and the entire objective of classification would not be achieved.
Classification of animals is also important in comparing different organisms and judging their individual evolutionary significance. If only a single characteristic is considered, then this objective would not be achieved.
They are known as acoelomates. An example of acoelomates is platyhelminthes.
Peculiar features in parasitic platyhelminthes are as follows.
They have dorsiventrally flattened body and bear hooks and suckers to get attached inside the body of the host.
Their body is covered with thick tegument, which protects them from the action of digestive juices of the host.
The tegument also helps in absorbing nutrients from the host’s body.
Jointed legs that allow more mobility on land
Hard exoskeleton made of chitin that protects the body
The hard exoskeleton also reduces water loss from the body of arthropods making them more adapted to terrestrial conditions.
Streamlined body for rapid and smooth movement
Covering of feathers for insulation
Forelimbs modified into wings and hind limbs used for walking, perching, and swimming
Presence of pneumatic bones to reduce weight
Presence of additional air sacs to supplement respiration