Structural Organization in Animals: Frogs

Introduction to Frogs

• Topic introduced: Structural organization in animals focusing on frogs.
• Common Indian frog: Rana tigrina (scientific name).
• Classification: Frogs are amphibians, belonging to class Amphibia.

Characteristics of Amphibians

• Habitat: Can live in both water and land.
• Reproduction: Requires water for breeding; often found near water bodies.
• Seasonal Activity: Active during the rainy season for breeding.
• Metabolism: Undergo hibernation (winter) and activation (summer) due to cold-blooded nature (poikilothermic).

Hibernation and Activation

• Cold-blooded (poikilothermic) animals cannot maintain a constant body temperature.
• When external temperature drops (4-5 degrees Celsius), their metabolism slows.
• They enter hibernation or summer sleep (activation) to survive extreme temperatures.
• Store reserve food and burrow in mud during these periods.

Morphology of Frogs

• Skin Color: Typically olive green but can change color (camouflage and mimicry).
  • Dorsal side (top): Olive green to brown depending on surroundings.
  • Ventral side (bottom): Pale yellow.
• Body Structure: Divisible into head and trunk (no neck or tail in adults).
• Eyes: Bulging eyes are prominent.
• Limbs:
  • Hind limbs: Longer and stronger for jumping/leaping; have webbed feet.
  • Forelimbs: Smaller and weaker than hind limbs.

Distinguishing Male and Female Frogs

• Sexual Dimorphism: Males and females can be distinguished by specific features:
  • Male Frogs:
    • Have copulatory pads (nuptial pads) on the first digit of forelimbs (ventral side).
    • Possess vocal cords (vocal sacs) that create croaking sounds to attract females.
  • Female Frogs: Do not have these pads or vocal sacs.

Summary of Morphology

• Frogs have a streamlined body for swimming efficiency.
• Features like webbed feet and absence of a neck aid in aquatic movement.
• The morphology discussed lays the foundation for further topics like respiration and skin functions.