Animal Kingdom Part - Detailed Notes

1. Classification of Animals:

• Levels of Classification: Phylum, Class, Order, Family, Genus, Species.

  • NCERT Reference: Class 11, Biology, Chapter 1: The Living World.

• Binomial Nomenclature:

  • NCERT Reference: Class 11, Biology, Chapter 1: The Living World.

2. Porifera (Sponges):

• General Characteristics and Body Plan:

  • Multicellular, sessile animals.
  • Porous body with a canal system for water circulation.
  • Choanocytes - cells responsible for filter feeding.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Canal System and Choanocytes:

  • Choanocytes line the canals and filter food particles from the water.
  • Water enters through small pores and exits through a larger opening called the osculum.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Importance of Sponges in the Marine Ecosystem:

  • Provide food and shelter for other organisms.
  • Help filter and clean the water.
  • Used in the production of medicines and cosmetics.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

3. Coelenterates (Cnidarians):

• General Characteristics and Body Plan (Polyp and Medusa Forms):

  • Multicellular, diploblastic animals.
  • Two basic body forms - polyp (attached) and medusa (free-swimming).
  • Cnidocytes - stinging cells used for capturing prey and defense.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Cnidocytes and Their Functions:

  • Cnidocytes contain a venom-filled capsule called a nematocyst.
  • Nematocysts are triggered by contact and release venom to immobilize prey or deter predators.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Coral Reefs and Their Significance:

  • Formed by colonies of corals, which are marine cnidarians.
  • Provide habitat and shelter for diverse marine life.
  • Important for tourism and fisheries.
  • Vulnerable to climate change and human activities.
  • NCERT Reference: Class 12, Biology, Chapter 13: Organisms and Populations.

4. Platyhelminthes (Flatworms):

• General Characteristics and Body Plan:

  • Multicellular, acoelomate animals.
  • Flat, dorsoventrally flattened body.
  • Parasitic and free-living species.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Parasitic Adaptations in Flatworms (Examples Like Taenia and Fasciola):

  • Taenia (Tapeworm): Adaptations for absorbing nutrients from the host’s intestine, proglottids for reproduction.
  • Fasciola (Liver Fluke): Adaptations for living in the liver of host, complex life cycle involving multiple hosts.
  • NCERT Reference: Class 11, Biology, Chapter 4: Animal Kingdom.

5. Nemathelminthes (Roundworms):

• General Characteristics and Body Plan:

  • Multicellular, pseudocoelomate animals.
  • Cylindrical, unsegmented body.
  • Parasitic and free-living species.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Parasitic Adaptations in Roundworms (Ascaris and Wuchereria):

  • Ascaris (Roundworm): Adaptations for living in the intestine of humans, muscular body for attachment, high reproductive rate.
  • Wuchereria (Filarial Worm): Adaptations for living in the lymphatic system of humans, transmitted by mosquitoes, causes elephantiasis.
  • NCERT Reference: Class 11, Biology, Chapter 4: Animal Kingdom.

6. Annelids (Segmented Worms):

• General Characteristics and Body Plan (Earthworms and Leeches):

  • Multicellular, coelomate animals.
  • Metamerically segmented body.
  • Closed circulatory system with blood vessels.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Earthworms - Their Role in Soil Aeration and Nutrient Cycling:

  • Burrowing and burrowing of earthworms improves soil aeration.
  • Earthworms feed on organic matter and excrete castings, which enriches the soil with nutrients.
  • NCERT Reference: Class 12, Biology, Chapter 13: Organisms and Populations.

7. Mollusca:

• General Characteristics and Body Plan:

  • Multicellular, coelomate animals.
  • Soft body, often enclosed in a calcareous shell.
  • Open circulatory system with a heart and blood vessels.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Classification into Major Groups (Bivalves, Gastropods, Cephalopods):

  • Bivalves: Mollusks with two shells, such as clams and mussels.
  • Gastropods: Mollusks with a single shell, such as snails and slugs.
  • Cephalopods: Mollusks with reduced or no shell, such as squid, octopus, and cuttlefish.
  • NCERT Reference: Class 11, Biology, Chapter 4: Animal Kingdom.

• Economic Importance of Mollusks (Pearl Formation, Edible Species):

  • Pearls are formed when oysters or other bivalves secrete layers of nacre around an irritant.
  • Many mollusks, such as oysters, clams, scallops, and squid, are important food sources.
  • NCERT Reference: Class 11, Biology, Chapter 4: Animal Kingdom.

8. Echinoderms:

• General Characteristics and Body Plan (Starfish, Sea Urchin):

  • Multicellular, coelomate animals.
  • Radial symmetry.
  • Unique water vascular system with tube feet for locomotion and feeding.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Water Vascular System and Its Role in Locomotion and Feeding:

  • Water vascular system consists of a network of canals and tube feet.
  • Tube feet are used for locomotion, capturing prey, and sensing the environment.
  • NCERT Reference: Class 11, Biology, Chapter 4: Animal Kingdom.

9. Protochordates:

• General Characteristics and Body Plan (Amphioxus, Tunicates):

  • Multicellular, coelomate animals.
  • Bilateral symmetry.
  • Presence of notochord, a flexible rod-like structure.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Significance of Protochordates in Understanding Vertebrate Evolution:

  • Protochordates share some features with vertebrates, making them important in understanding the evolutionary relationship between invertebrates and vertebrates.
  • Amphioxus is often used as a model organism to study early developmental processes in vertebrates.
  • NCERT Reference: Class 11, Biology, Chapter 9: Strategies for Enhancement in Food Production.

10. Vertebrates:

• General Characteristics and Classification (Fishes, Amphibians, Reptiles, Birds, and Mammals):

  • Multicellular, coelomate animals with a backbone (vertebral column).
  • Classification into major groups based on key features and evolutionary relationships.
  • NCERT Reference: Class 11, Biology, Chapter 2: Biological Classification.

• Comparative Anatomy of Major Vertebrate Groups:

  • Comparative study of the skeletal, muscular, digestive, circulatory, respiratory, excretory, and reproductive systems of different vertebrate groups.
  • NCERT Reference: Class 11, Biology, Chapter 9: Strategies for Enhancement in Food Production.

• Evolutionary Relationships Among Vertebrates:

  • Phylogenetic trees and cladograms are used to depict the evolutionary relationships among different vertebrate groups.
  • Understanding the common ancestor and derived characters help trace the evolutionary history of vertebrates.

For further details, refer to NCERT Biology textbooks for Class 11 and Class 12, especially the chapters mentioned in the reference section.