CBSE Class 11 Biology Notes Chapter 4 Animal Kingdom PDF Download

CBSE Class 11 Biology Notes Chapter 4: In CBSE Class 11 Biology, Chapter 4 talks about the Animal Kingdom. It's all about different types of animals and how we classify them. We look at things like their shape, if they have a backbone, and what their body is like inside.

CBSE Class 11 Biology Notes Chapter 4 Animal Kingdom PDF Download

CBSE Class 11 Biology Notes

CBSE Class 11 Biology Notes Chapter 4 Animal Kingdom PDF

CBSE Class 11 Biology Notes Chapter 4 Animal Kingdom

Animal Kingdom

• Cellular level of organization: This is the simplest level, where cells are loosely put together, seen in creatures like sponges.
• Tissue level of organization: Cells doing the same job form tissues, seen in animals like coelenterates.
• Organ level of organization: Tissues group up to form organs that do specific jobs, like in flatworms.
• Organ system level of organization: Here, a bunch of organs work together for a particular function, seen in animals like annelids and arthropods.

• Open circulatory system: Blood is pumped out of the heart directly to the cells and tissues.
• Closed circulatory system: Blood moves around in a network of tubes like arteries, veins, and capillaries.

• Diploblastic: The embryo has two layers, like sponges and cnidarians.
• Triploblastic: The embryo has three layers, with mesoderm between the outer and inner layers, seen in animals from flatworms to chordates.

• Asymmetrical: No symmetry, like in sponges.
• Radial symmetry: The body can be split into equal halves by any plane passing through the center, seen in animals like jellyfish.
• Bilateral symmetry: The body can be split into equal left and right halves, seen in animals like worms and insects.

• Acoelomates: No body cavity, like flatworms.
• Pseudocoelomates: Their body cavity is filled with scattered pouches of mesoderm, like roundworms.
• Coelomates: They have a proper body cavity, seen in animals from segmented worms to vertebrates.

Classification of Animals

Classification of the Animal Kingdom based on common fundamental features

Phylum – Porifera (Sponges)

• Found in the ocean, asymmetrical shape, and cellular level of organization.
• They take in food, exchange gases, and excrete waste through water flow.
• Water enters through pores and exits through an opening called osculum.
• The inner cavity, spongocoel, is lined with collar cells or choanocytes.
• They have a skeleton made of spongin fibers or spicules.
• Sponges can reproduce both asexually and sexually, and they're hermaphrodites.

Phylum – Coelenterata (Cnidaria)

• Aquatic animals, either stationary or free-swimming, with tissue-level organization and radial symmetry.
• They have a central digestive cavity with a single opening surrounded by sensory tentacles.
• Special cells called cnidoblasts on tentacles contain stinging structures called nematocysts.
• Digestion is both inside and outside the body.
• Some have a hard skeleton made of calcium carbonate.
• They exist in two forms: polyps (sessile) and medusae (free-swimming).
• Some undergo alternation of generations, producing offspring asexually and sexually.

Phylum – Ctenophora (Comb jellies)

• Marine animals with tissue-level organization, radial symmetry, and no body cavity.
• They have eight rows of cilia-covered comb plates for locomotion.
• Digestion happens both inside and outside their bodies.
• Some species can produce light (bioluminescence).
• They can reproduce both sexually and externally, and they're hermaphrodites.

Phylum – Platyhelminthes (Flatworms)

• Mostly parasitic worms with flattened bodies, bilateral symmetry, and no body cavity.
• Parasites have hooks and suckers for attachment.
• They have flame cells for osmoregulation and excretion.
• Flatworms are hermaphrodites and can regenerate.
• Reproduction is both internal and through larval stages.

Phylum – Aschelminthes

• These are either free-living or parasitic, found in water or on land.
• They have round bodies, bilateral symmetry, and a pseudocoelom.
• Their digestive system is complete with a muscular pharynx.
• They reproduce sexually, with females usually longer than males.
• Examples include Ascaris (roundworm), Wuchereria (Filarial worm), and Ancylostoma (hookworm).

Phylum – Annelida

• These creatures have bilateral symmetry, a true coelom, and segmented bodies.
• Longitudinal and circular muscles aid in movement.
• They have closed circulatory systems and nephridia for waste removal.
• Reproduction is usually sexual, with some species being hermaphrodites.
• Examples are Pheretima (earthworm), Nereis, and Hirudinaria (bloodsucking leech).

Phylum – Arthropoda

• This is the largest phylum, containing insects.
• They have bilateral symmetry, a true coelom, and jointed legs.
• Their bodies are covered by a hard exoskeleton made of chitin.
• Respiration occurs through various methods like trachea, gills, or book lungs.
• They have open circulatory systems and compound or simple eyes.
• Examples include economically important species like Bombyx (silkworm) and disease vectors like mosquitoes.

Phylum – Mollusca

• These animals have bilateral symmetry, a true coelom, and a shell.
• They have distinct body parts like a head, foot, and visceral hump.
• Respiration and waste removal happen through feather-like gills.
• They have a rasping organ called a radula for feeding.
• Reproduction is usually sexual, with indirect development.
• Examples include Pila (apple snail), Octopus, and Pearl oyster.

Phylum – Echinodermata

• Adults show radial symmetry, while larvae have bilateral symmetry.
• They have a true coelom and an endoskeleton made of calcareous ossicles.
• Echinoderms have a unique water vascular system for various functions.
• Reproduction is usually sexual with indirect development.
• Examples include Asterias (starfish), Ophiura (brittle star), and Echinus (sea urchin).

Phylum – Hemichordata

• They have features similar to both chordates and invertebrates.
• They possess a structure called a stomochord resembling a notochord.
• Hemichordates have bilateral symmetry and a coelom.
• They reproduce sexually, with indirect development.
• Examples include Balanoglossus and Saccoglossus.

Phylum – Chordata

• Chordates are characterized by a hollow nerve cord, notochord, and gill slits.
• They have bilateral symmetry, a true coelom, and a closed circulatory system.
• Chordata is divided into three subphyla: Urochordata, Cephalochordata, and Vertebrata.
• Vertebrata is further divided into Agnatha (jawless) and Gnathostomata (jawed), which includes Pisces and Tetrapoda.
• Examples include various fish species, amphibians, reptiles, birds, and mammals.

Class I – Cyclostomata (Circular Mouthed Fishes)

• These fishes have a circular and sucking mouth without jaws.
• They are ectoparasites on other fishes.
• Cyclostomes have 6-15 pairs of gill slits, with no scales or fins.
• They have a cartilaginous vertebral column and closed circulation.
• Examples include Petromyzon (Lamprey) and Myxine (Hagfish).

Class II – Chondrichthyes (Cartilaginous fishes)

• These fishes have a cartilaginous endoskeleton and their mouth is on the ventral side.
• They lack operculum covering the gills.
• Chondrichthyes have placoid scales on their skin.
• They maintain buoyancy by constant swimming as they lack air bladders.
• Examples include Scoliodon (Dogfish), Trygon (Stingray), and Carcharodon (Great white shark).

Class III – Osteichthyes (Bony fishes)

• These fishes have a streamlined body with a bony endoskeleton.
• They possess cycloid scales on their skin.
• Osteichthyes have a two-chambered heart and an air bladder for buoyancy.
• Examples include marine species like Hippocampus (Sea horse) and freshwater species like Labeo (Rohu).

Class IV – Amphibia

• Amphibians can live both in water and on land.
• They typically have moist skin and lay eggs in water.
• Examples include frogs, salamanders, and limbless salamanders like Ichtthyophis.

Class V – Reptilia

• Reptiles are mostly terrestrial and have dry, cornified skin with scales or scutes.
• They lay eggs on land and have internal fertilization.
• Examples include crocodiles, alligators, chameleons, and snakes like Naja and Viper.

Class VI – Aves

• Birds have feathers for flying and their forelimbs are modified into wings.
• They have dry skin with oil glands and pneumatic bones for flight.
• Birds lay eggs with hard shells and exhibit internal fertilization.
• Examples include crows, pigeons, parrots, and flightless birds like ostriches.

Class VII – Mammalia

• Mammals are mostly terrestrial but some can fly or live in water.
• They have skin covered in hair or fur and mammary glands to feed their young.
• Mammals have a four-chambered heart and are warm-blooded.
• They give birth to live young and exhibit internal fertilization.
• Examples include kangaroos, cats, lions, and marine mammals like dolphins.

Benefits of CBSE Class 11 Biology Notes Chapter 4

• These notes provide a comprehensive overview of the Animal Kingdom, covering various aspects such as classification, characteristics, and examples of different animal phyla.
• The notes are organized in a structured manner, making it easier for students to follow and understand the concepts sequentially.
• Complex biological concepts are simplified in these notes, enhancing clarity and making it easier for students to grasp the content.
• Students can use these notes for self-study purposes, allowing them to review the material at their own pace and reinforce their understanding of the Animal Kingdom.