Animal Kingdom (Chordates) Handwritten Notes PDF Download

Description

1. Introduction to Chordates

• Definition: Chordates are animals possessing a notochord, a hollow dorsal nerve cord, pharyngeal slits, and a post-anal tail at some point in their life cycle.
• Characteristics:
  • Notochord: A flexible, rod-shaped structure found in the embryonic stage of all chordates.
  • Dorsal Nerve Cord: Develops into the brain and spinal cord.
  • Pharyngeal Slits: Openings in the pharynx that develop into gill structures in aquatic chordates.
  • Post-Anal Tail: Extension of the body past the anal opening.

2. Classification of Chordates

• Three Subphyla:
  • Urochordata (Tunicates):
    • Marine organisms.
    • Notochord present only in the larval stage.
    • Examples: Sea squirts.
  • Cephalochordata (Lancelets):
    • Marine organisms.
    • Notochord extends throughout life.
    • Examples: Amphioxus.
  • Vertebrata (Craniata):
    • Have a vertebral column.
    • Includes fishes, amphibians, reptiles, birds, and mammals.

3. Subphylum Vertebrata

• Characteristics:
  • Endoskeleton: Made of cartilage or bone.
  • Complex Nervous System: Highly developed brain enclosed in a skull.
  • Closed Circulatory System: Heart with two, three, or four chambers.
  • Excretory System: Kidneys filter waste products from the blood.

4. Classes of Vertebrates

• Agnatha (Jawless Fishes):
  • Lack jaws and paired fins.
  • Examples: Lampreys, hagfish.
• Chondrichthyes (Cartilaginous Fishes):
  • Skeleton made of cartilage.
  • Examples: Sharks, rays.
• Osteichthyes (Bony Fishes):
  • Skeleton made of bone.
  • Examples: Salmon, goldfish.
• Amphibia (Amphibians):
  • Dual life: aquatic larval stage and terrestrial adult stage.
  • Examples: Frogs, salamanders.
  • Reptilia (Reptiles):
  • Scaly skin, lay shelled eggs.
  • Examples: Snakes, lizards, turtles.
  • Aves (Birds):
  • Feathers, beak, lay eggs, endothermic.
  • Examples: Eagles, sparrows.
  • Mammalia (Mammals):
  • Hair or fur, mammary glands, endothermic.
  • Examples: Humans, whales, elephants.
  • 5. Adaptations in Chordates
  • Respiratory Adaptations:
  • Gills in fishes.
  • Lungs in amphibians, reptiles, birds, and mammals.
  • Reproductive Adaptations:
  • Oviparous (egg-laying) and viviparous (live-bearing) species.
  • Locomotory Adaptations:
  • Fins in fishes.
  • Limbs in amphibians, reptiles, birds, and mammals.
  • Sensory Adaptations:
  • Highly developed eyes, ears, and olfactory systems.
  • 6. Examples and Economic Importance
  • Fishes: Important for food, sport, and aquarium trade.
  • Amphibians: Indicators of environmental health, pest control.
  • Reptiles: Control rodent populations, some are pets.
  • Birds: Pollination, seed dispersal, pest control, food.
  • Mammals: Domesticated animals for food, labor, and companionship.