Amphibian Reproduction Notes

Amphibian Reproduction and Water Dependence

Dependence on Water

• Amphibians are strongly tied to water sources throughout their lives.

Respiration

• Many amphibians breathe through their skin, which requires moisture.

Fertilization and Reproduction

• Most amphibians use internal insemination or internal fertilization but are still egg-layers.

• They need to return to the water to breed.

Road Impact

• Roads kill approximately 15-20 tonnes of amphibians per year.

Egg Laying Strategies

• Various strategies exist, from multiple chains of eggs to singular eggs laid upon leaves.

• Some species try to extend their range if possible.

Parental Care Examples

• Strawberry Poison Dart Frog:
  • Returns to water eggs.
  • Lays eggs in basin plants and comes back to water them.
• Cream-backed Poison Frog:
  • Carries offspring to water.
  • Holds water for its young.
• Common Midwife Toad:
  • Carries eggs on its back.
• Rangara Frog:
  • Produces floating foam near to lay eggs.
  • Lays eggs in a biofilm to protect tadpoles.
  • The biofilm has antimicrobials.
• Pouched Frogs:
  • Layer of water to cover eggs is created.
• Darwining Frogs:
  • Engulf eggs in vocal pouch with frothy nutrient film.

Water Dependence

• All parts of the amphibians' lives are limited to a water source.