Karthikeyan

Amphibia

General Characteristics

• Cold-blooded vertebrates

• Four limbs

• No scales; skin is moist

• Name amphibian means “double life” (water + land)

• Examples: frogs, toads, newts

• Carnivorous (feed on other animals)

Habitat & Lifestyle

• Live mostly on moist land

• Return to water to lay eggs

• Depend on water for reproduction

Body Features

• Frogs & toads: no tail

• Newts: have a tail

• Toad’s skin:

  • Drier than frog’s skin

  • Has glands that release bad-tasting chemicals to deter predators

Limbs & Movement

• Four limbs

• Frogs and toads:

  • Hind feet have webbed toes

  • Helps in swimming

• Newts:

  • Swim using fish-like wriggling movements

  • Limbs used less for swimming

Respiration

• Moist skin with many capillaries for gas exchange

• Also have lungs

• Air is taken in by a swallowing action

• No ribs or diaphragm

Reproduction

• Migrate to ponds

• External fertilisation

• Male grips female; releases sperms over eggs as they are laid

Reptiles

General Characteristics

• Cold-blooded, land-living vertebrates

• Skin is dry and scaly

• Scales reduce water loss

• Examples:

  • Lizards, snakes, turtles, tortoises, crocodiles

Habitat & Adaptations

• Not limited to damp places

• Eggs have a tough, leathery shell

• Do not need water for breeding

Temperature Regulation

• Cold-blooded but can regulate body temperature

• Bask in sunlight to warm up

• Warm reptiles move faster and hunt better

Limbs

• Most reptiles:

  • Four limbs

  • Each limb has five toes

• Snakes:

  • No limbs

  • Some still have traces of limb bones

Reproduction

• Internal fertilisation

• Sperms passed into female’s body

• In some species:

  • Eggs are kept inside until they hatch