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Animal Kingdom Class 11 Biology NCERT notes with detailed summary, MCQs, keywords, questions-answers, flowchart and exam tips. Simple, SEO-friendly, and student-oriented.
Introduction of the Chapter: Animal Kingdom
The Animal Kingdom chapter in Class 11 Biology (NCERT) deals with the scientific study of animals and their classification based on fundamental characteristics. This chapter is extremely important for school exams, NEET, and other competitive examinations. It introduces students to the vast diversity of animals and helps them understand how animals are grouped systematically.
The Animal Kingdom includes all multicellular, heterotrophic organisms that lack cell walls. Animals show a wide range of structural and functional diversity. To study such diversity easily, scientists have classified animals into different phyla based on criteria like level of organization, symmetry, coelom, segmentation, and presence or absence of notochord.
Understanding the Animal Kingdom helps students build a strong foundation in taxonomy, evolution, and comparative anatomy. This chapter emphasizes the importance of classification in identifying similarities and differences among animals. NCERT-based questions from the Animal Kingdom are frequently asked in exams, making it a high-weightage chapter.
Short Notes on Animal Kingdom
- Animals are multicellular, eukaryotic, and heterotrophic organisms
- Most animals show locomotion at some stage of life
- Classification is based on structural and embryological features
- Levels of organization: cellular, tissue, organ, organ system
- Body symmetry: asymmetrical, radial, bilateral
- Coelom types: acoelomate, pseudocoelomate, coelomate
- Segmentation may be present or absent
- Notochord is the key feature for chordates
- Non-chordates lack notochord
- Chordates include vertebrates and protochordates
Detailed Summary of Animal Kingdom (800–900 Words)
The Animal Kingdom represents one of the largest and most diverse groups of organisms on Earth. Members of the animal kingdom vary greatly in size, shape, habitat, and mode of life. Despite this diversity, animals share some common features such as multicellularity, heterotrophic nutrition, and absence of a rigid cell wall.
To simplify the study of such diversity, animals are classified into various groups based on specific criteria. The basis of classification in the Animal Kingdom includes levels of organization, symmetry, germ layers, body cavity, segmentation, and notochord.
Levels of Organization
Animals exhibit different levels of organization. The simplest animals show a cellular level of organization, where cells perform all functions. Sponges exhibit this level. More complex animals show tissue, organ, or organ system level of organization, allowing specialization of functions.
Body Symmetry
Body symmetry refers to the arrangement of body parts around a central axis. Animals may be asymmetrical, radially symmetrical, or bilaterally symmetrical. Radial symmetry is common in aquatic animals like cnidarians, while bilateral symmetry is seen in most advanced animals.
Germ Layers
During embryonic development, animals form germ layers. Diploblastic animals have two germ layers, while triploblastic animals have three. This feature is important for understanding body complexity in the Animal Kingdom.
Coelom
The presence or absence of a body cavity called coelom is another classification criterion. Animals may be acoelomate, pseudocoelomate, or coelomate. Coelom provides space for internal organs and allows efficient movement.
Segmentation
In some animals, the body is divided into repeated segments. This segmentation is called metamerism and provides flexibility and specialization.
Classification of Animal Kingdom
The Animal Kingdom is broadly divided into non-chordates and chordates.
Non-Chordates
Non-chordates do not possess a notochord. They include phyla such as Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, and Hemichordata. Arthropoda is the largest phylum and includes insects, crustaceans, and arachnids.
Chordates
Chordates possess a notochord, dorsal hollow nerve cord, pharyngeal gill slits, and post-anal tail at some stage of life. They are divided into protochordates and vertebrates. Vertebrates have a vertebral column replacing the notochord.
The Animal Kingdom classification helps in understanding evolutionary relationships and adaptations. This systematic arrangement allows scientists and students to identify organisms correctly and study their biology efficiently.
Flowchart / Mind Map (Text-Based)
Animal Kingdom
→ Non-Chordata
→ Porifera
→ Cnidaria
→ Platyhelminthes
→ Nematoda
→ Annelida
→ Arthropoda
→ Mollusca
→ Echinodermata
→ Hemichordata
→ Chordata
→ Protochordata
→ Vertebrata
→ Pisces
→ Amphibia
→ Reptilia
→ Aves
→ Mammalia
Important Keywords with Meanings
- Heterotrophic – Dependent on others for food
- Coelom – Body cavity between gut and body wall
- Notochord – Flexible supporting rod in chordates
- Radial symmetry – Body parts arranged around axis
- Bilateral symmetry – Right and left halves equal
- Metamerism – Segmented body plan
- Diploblastic – Two germ layers
- Triploblastic – Three germ layers
- Vertebrate – Animal with backbone
- Invertebrate – Animal without backbone
Important Questions & Answers
Short Answer Questions (10)
- What is the basis of classification in Animal Kingdom?
Answer: Structural, embryological, and morphological features. - Define notochord.
Answer: A rod-like structure present in chordates. - What is bilateral symmetry?
Answer: Body divisible into two equal halves. - Name the largest phylum of Animal Kingdom.
Answer: Arthropoda. - What are diploblastic animals?
Answer: Animals with two germ layers. - Define coelom.
Answer: Fluid-filled body cavity. - Give one example of mollusca.
Answer: Snail. - What is metamerism?
Answer: Segmentation of the body. - What is the level of organization in sponges?
Answer: Cellular level. - Name one chordate feature.
Answer: Dorsal hollow nerve cord.
Exam Tips / Value-Based Questions
Exam Tips
- Draw neat classification flowcharts
- Learn examples for each phylum
- Focus on differences between groups
- Practice MCQs regularly
- Revise keywords before exams
Value-Based Questions (5)
- Why is classification important in biology?
Answer: It helps in systematic study and conservation. - How does biodiversity benefit humans?
Answer: It maintains ecological balance. - Why should animals be protected?
Answer: They are essential for ecosystems. - What values are promoted by studying Animal Kingdom?
Answer: Respect for nature and biodiversity. - How does scientific classification help society?
Answer: It supports research and education.
Conclusion: Animal Kingdom (SEO-Friendly)
The Animal Kingdom chapter of Class 11 Biology NCERT is a foundational topic that introduces students to the immense diversity of animals and the scientific principles behind their classification. By studying the Animal Kingdom, students gain a clear understanding of how animals are grouped based on structural, functional, and developmental characteristics.
A strong command over the Animal Kingdom helps students perform well in board exams as well as competitive examinations like NEET. The chapter enhances analytical thinking by encouraging comparison between different animal groups. It also highlights the importance of biodiversity and conservation.
The systematic classification of the Animal Kingdom simplifies learning and helps students remember key features and examples. This chapter connects concepts of evolution, anatomy, and ecology, making it one of the most scoring units in Class 11 Biology.
Regular revision of Animal Kingdom notes, MCQs, keywords, and diagrams is essential for exam success. With clear concepts and proper practice, students can easily master the Animal Kingdom and build a strong base for higher studies in biological sciences.
compitative long Questions:
1. Explain the Basis of Classification of Animal Kingdom
The classification of the Animal Kingdom is based on fundamental structural and embryological features. These criteria help in grouping animals with similar characteristics and understanding their evolutionary relationships.
Major Bases of Classification
1. Level of Organization
Animals show different levels of structural organization:
- Cellular level – Cells are loosely arranged (Porifera)
- Tissue level – Cells form tissues (Cnidaria)
- Organ level – Tissues form organs (Platyhelminthes)
- Organ system level – Organs form systems (Annelida onwards)
2. Body Symmetry
- Asymmetrical – No symmetry (Sponges)
- Radial symmetry – Body parts arranged around central axis (Cnidaria, Echinodermata)
- Bilateral symmetry – Body divisible into two equal halves (Most animals)
3. Germ Layers
- Diploblastic – Two germ layers (ectoderm and endoderm)
- Triploblastic – Three germ layers (ectoderm, mesoderm, endoderm)
4. Body Cavity (Coelom)
- Acoelomate – No body cavity (Platyhelminthes)
- Pseudocoelomate – False coelom (Nematoda)
- Coelomate – True coelom (Annelida onwards)
5. Segmentation
Presence of repeated body segments (Annelida, Arthropoda)
6. Presence of Notochord
- Non-chordates – Notochord absent
- Chordates – Notochord present
Thus, the Animal Kingdom classification is scientific, logical, and helps in systematic study.
2. Describe Phylum Arthropoda with Examples
Arthropoda is the largest phylum of the Animal Kingdom and includes insects, spiders, crustaceans, and millipedes.
General Characteristics
- Body is segmented
- Presence of jointed appendages
- Bilateral symmetry
- Triploblastic and coelomate
- Hard chitinous exoskeleton
- Open circulatory system
- Respiration by gills, trachea, or book lungs
- Sexes usually separate
Examples
- Cockroach
- Butterfly
- Crab
- Spider
- Scorpion
Importance
- Pollination (insects)
- Food source (prawns, crabs)
- Some are disease vectors (mosquito)
Arthropoda shows maximum diversity and adaptability in the Animal Kingdom.
3. Differentiate Between Chordates and Non-Chordates
| Feature | Chordates | Non-Chordates |
|---|---|---|
| Notochord | Present | Absent |
| Nerve cord | Dorsal, hollow | Ventral, solid |
| Gill slits | Present | Absent |
| Post-anal tail | Present | Absent |
| Heart position | Ventral | Dorsal or absent |
Examples
- Chordates: Fish, Frog, Bird, Human
- Non-chordates: Earthworm, Insect, Starfish
This distinction forms the major division of the Animal Kingdom.
4. Explain Levels of Organization in Animals
Animals differ in complexity based on how cells are organized.
1. Cellular Level
- Cells are loosely arranged
- No true tissues
- Example: Porifera
2. Tissue Level
- Cells form tissues
- Tissues perform specific functions
- Example: Cnidaria
3. Organ Level
- Tissues combine to form organs
- Example: Platyhelminthes
4. Organ System Level
- Organs work together as systems
- Highly specialized
- Example: Annelida to Chordata
Higher levels of organization indicate evolutionary advancement in the Animal Kingdom.
5. Describe the Classification of Vertebrates
Vertebrates belong to Phylum Chordata and have a backbone.
General Features
- Vertebral column present
- Notochord replaced by backbone
- Well-developed brain
- Closed circulatory system
Classes of Vertebrates
1. Pisces
- Aquatic
- Fins for locomotion
- Respiration by gills
Example: Rohu
2. Amphibia
- Live on land and water
- Moist skin
Example: Frog
3. Reptilia
- Dry, scaly skin
- Cold-blooded
Example: Snake
4. Aves
- Feathers and wings
- Warm-blooded
Example: Pigeon
5. Mammalia
- Mammary glands
- Hair present
- Warm-blooded
Example: Human
Vertebrates represent the most advanced group in the Animal Kingdom.
Animal Kingdom – MCQs with Answers
1. Animals showing cellular level of organization belong to
A. Cnidaria
B. Porifera
C. Annelida
D. Arthropoda
Answer: B
2. Which symmetry is found in Hydra?
A. Bilateral
B. Asymmetrical
C. Radial
D. Spherical
Answer: C
3. Diploblastic animals possess
A. Three germ layers
B. Two germ layers
C. No germ layers
D. Four germ layers
Answer: B
4. Which phylum is acoelomate?
A. Nematoda
B. Annelida
C. Arthropoda
D. Platyhelminthes
Answer: D
5. Presence of pseudocoelom is seen in
A. Platyhelminthes
B. Annelida
C. Nematoda
D. Mollusca
Answer: C
6. Metameric segmentation is characteristic of
A. Mollusca
B. Annelida
C. Echinodermata
D. Cnidaria
Answer: B
7. Which is the largest phylum of Animal Kingdom?
A. Mollusca
B. Arthropoda
C. Chordata
D. Annelida
Answer: B
8. Jointed appendages are found in
A. Annelida
B. Mollusca
C. Arthropoda
D. Echinodermata
Answer: C
9. Open circulatory system is present in
A. Annelida
B. Arthropoda
C. Chordata
D. Platyhelminthes
Answer: B
10. Which phylum shows water vascular system?
A. Mollusca
B. Arthropoda
C. Echinodermata
D. Annelida
Answer: C
11. Adult echinoderms are
A. Bilaterally symmetrical
B. Radially symmetrical
C. Asymmetrical
D. Cylindrical
Answer: B
12. Which phylum includes earthworm?
A. Arthropoda
B. Mollusca
C. Annelida
D. Nematoda
Answer: C
13. Which is a triploblastic animal?
A. Hydra
B. Sponge
C. Planaria
D. Jellyfish
Answer: C
14. Notochord is present in
A. All animals
B. Non-chordates
C. Chordates
D. Arthropods
Answer: C
15. Dorsal hollow nerve cord is a feature of
A. Mollusca
B. Annelida
C. Arthropoda
D. Chordata
Answer: D
16. Which of the following is a protochordate?
A. Starfish
B. Earthworm
C. Balanoglossus
D. Cockroach
Answer: C
17. Vertebral column is present in
A. Protochordates
B. Invertebrates
C. Vertebrates
D. Hemichordates
Answer: C
18. Fish belong to which class?
A. Amphibia
B. Pisces
C. Reptilia
D. Mammalia
Answer: B
19. Amphibians are
A. Fully aquatic
B. Fully terrestrial
C. Live on land and water
D. Aerial
Answer: C
20. Dry and scaly skin is a feature of
A. Amphibia
B. Aves
C. Reptilia
D. Mammalia
Answer: C
21. Feathers are characteristic of
A. Mammalia
B. Reptilia
C. Aves
D. Amphibia
Answer: C
22. Mammary glands are found in
A. Aves
B. Amphibia
C. Reptilia
D. Mammalia
Answer: D
23. Warm-blooded animals include
A. Pisces and Amphibia
B. Reptilia and Amphibia
C. Aves and Mammalia
D. Pisces and Reptilia
Answer: C
24. Which animal shows bilateral symmetry?
A. Starfish
B. Hydra
C. Human
D. Sponge
Answer: C
25. Respiration through tracheae occurs in
A. Earthworm
B. Cockroach
C. Fish
D. Frog
Answer: B
26. Body cavity lined by mesoderm is called
A. Pseudocoelom
B. Acoelom
C. Coelom
D. Haemocoel
Answer: C
27. Example of mollusca is
A. Frog
B. Cockroach
C. Snail
D. Starfish
Answer: C
28. Which animal is a non-chordate?
A. Frog
B. Fish
C. Bird
D. Earthworm
Answer: D
29. Which feature is absent in non-chordates?
A. Segmentation
B. Coelom
C. Notochord
D. Symmetry
Answer: C
30. Animal Kingdom classification helps in
A. Confusion
B. Random study
C. Systematic study
D. Ignoring diversity
Answer: C
Sample Question Paper
Class 11 – Biology (NCERT)
Chapter: Animal Kingdom
General Instructions
•All questions are compulsory.
•The question paper consists of Section A, B, C, and D.
•Draw neat and labeled diagrams wherever necessary.
•Use simple and clear biological terminology.
SECTION – A (MCQs)
Choose the correct option.
1.Which phylum shows cellular level of organization?
a) Cnidaria
b) Porifera
c) Annelida
d) Arthropoda
2.Radial symmetry is found in
a) Earthworm
b) Human
c) Hydra
d) Cockroach
3.Diploblastic animals have
a) One germ layer
b) Two germ layers
c) Three germ layers
d) No germ layers
4.Acoelomate animals belong to phylum
a) Nematoda
b) Annelida
c) Platyhelminthes
d) Arthropoda
5.Jointed appendages are characteristic of
a) Mollusca
b) Arthropoda
c) Annelida
d) Echinodermata
6.Which phylum has water vascular system?
7.Notochord is present in
8.Largest phylum of Animal Kingdom is
9.Open circulatory system is found in
10.Adult echinoderms are
11.Vertebral column is present in
13.Example of mollusca is
13.Tracheal respiration occurs in
14.Amphibians live
15.Dry and scaly skin is seen in
16.Feathers are found in
17.Mammary glands are present in
18.Bilateral symmetry is seen in
19.Pseudocoelom is found in
20.Earthworm belongs to phylum
SECTION – B (Very Short Answer)
Answer in 2–4lines.
21.Define Animal Kingdom.
22.What is body symmetry?
23.Define coelom.
24.What is metamerism?
25.Name any two chordate features.
26.What is notochord?
27.Write two characteristics of Porifera.
28.What are diploblastic animals?
29.Name two examples of Arthropoda.
30.What is haemocoel?
SECTION – C (Short Answer)
Answer in 4–5 lines.
31.Explain levels of organization in animals.
32.Describe body cavity based classification.
33.Write characteristics of phylum Mollusca.
34.Differentiate between radial and bilateral symmetry.
35.Write three differences between chordates and non-chordates.
SECTION – D (Long Answer)
Answer in detail.
36.Explain the basis of classification of Animal Kingdom.
37.Describe phylum Arthropoda with examples.
38.Explain the classification of vertebrates.
END OF QUESTION PAPER
Below are the complete, correct, NCERT-based solutions for the Sample Question Paper: Animal Kingdom – Class 11 Biology.
Answers are exam-oriented, written in simple language, and follow CBSE marking style.
SOLUTIONS – SAMPLE QUESTION PAPER
Chapter: Animal Kingdom (Class 11 Biology)
SECTION A – MCQs (1×20 = 20 Marks)
- Porifera
- Hydra
- Two germ layers
- Platyhelminthes
- Arthropoda
- Echinodermata
- Chordata
- Arthropoda
- Arthropoda
- Radially symmetrical
- Vertebrates
- Snail
- Cockroach
- On land and in water
- Reptilia
- Aves
- Mammalia
- Human
- Nematoda
- Annelida
SECTION B – Very Short Answer (2×10 = 20 Marks)
21. Define Animal Kingdom.
The Animal Kingdom includes all multicellular, eukaryotic, heterotrophic organisms that lack cell walls.
22. What is body symmetry?
Body symmetry refers to the arrangement of body parts around a central axis or plane.
23. Define coelom.
Coelom is a fluid-filled body cavity between the digestive tract and the body wall.
24. What is metamerism?
Metamerism is the division of the body into repeated segments.
25. Name any two chordate features.
- Presence of notochord
- Dorsal hollow nerve cord
26. What is notochord?
Notochord is a flexible, rod-like structure present in chordates during some stage of life.
27. Write two characteristics of Porifera.
- Cellular level of organization
- Presence of water canal system
28. What are diploblastic animals?
Diploblastic animals have two germ layers: ectoderm and endoderm.
29. Name two examples of Arthropoda.
- Cockroach
- Butterfly
30. What is haemocoel?
Haemocoel is the blood-filled body cavity found in animals with open circulatory system.
SECTION C – Short Answer (3×5 = 15 Marks)
31. Explain levels of organization in animals.
Animals show different levels of organization:
- Cellular level – cells loosely arranged (Porifera)
- Tissue level – cells form tissues (Cnidaria)
- Organ level – tissues form organs (Platyhelminthes)
- Organ system level – organs form systems (Annelida onwards)
32. Describe body cavity based classification.
Animals are classified based on body cavity as:
- Acoelomate – no coelom (Platyhelminthes)
- Pseudocoelomate – false coelom (Nematoda)
- Coelomate – true coelom (Annelida onwards)
33. Write characteristics of phylum Mollusca.
- Soft, unsegmented body
- Bilateral symmetry
- Coelomate
- Body divided into head, muscular foot, and visceral mass
34. Differentiate between radial and bilateral symmetry.
| Radial Symmetry | Bilateral Symmetry |
|---|---|
| Body parts arranged around axis | Body divisible into two equal halves |
| Seen in Cnidaria | Seen in humans |
35. Write three differences between chordates and non-chordates.
| Chordates | Non-Chordates |
|---|---|
| Notochord present | Notochord absent |
| Dorsal nerve cord | Ventral nerve cord |
| Post-anal tail present | Post-anal tail absent |
SECTION D – Long Answer (5×3 = 15 Marks)
36. Explain the basis of classification of Animal Kingdom.
The classification of the Animal Kingdom is based on structural and developmental features:
- Level of Organization – cellular, tissue, organ, organ system
- Body Symmetry – asymmetrical, radial, bilateral
- Germ Layers – diploblastic or triploblastic
- Body Cavity (Coelom) – acoelomate, pseudocoelomate, coelomate
- Segmentation – presence or absence of metamerism
- Notochord – presence in chordates, absence in non-chordates
This scientific classification helps in systematic study and understanding of animal diversity.
37. Describe phylum Arthropoda with examples.
Arthropoda is the largest phylum of the Animal Kingdom.
Characteristics:
- Jointed appendages
- Segmented body
- Chitinous exoskeleton
- Bilateral symmetry
- Open circulatory system
Examples:
Cockroach, Butterfly, Crab, Spider
38. Explain the classification of vertebrates.
Vertebrates are chordates with a vertebral column.
Classes:
- Pisces – aquatic, gills, fins (Fish)
- Amphibia – live on land and water (Frog)
- Reptilia – dry scaly skin (Snake)
- Aves – feathers, wings (Birds)
- Mammalia – mammary glands (Human)
Vertebrates represent the most advanced animals.
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