Saltar la navegación

9.4. Adaptations of vertebrates to the terrestrial environment

Adaptations of vertebrates to the terrestrial environment

The animals, when they left the aquatic environment to colonize the terrestrial environment , had to face the problem of desiccation. Only those that had the necessary adaptations to avoid desiccation were able to conquer the terrestrial environment. Some of these adaptations are:

  • The skin: A skin is needed to isolate the organism from the environment and prevent water loss.
    • Reptiles: their skin is covered with scales, which prevents it from growing. This is the reason they have to shed their skin.
    • Mammals: They have fur covered skin.
    • Birds: Feathers cover their skin.
  • Efficient kidneys allow more water to be used by reducing its loss in excretion.
  • Movement: terrestrial vertebrates have four legs with which they can move or manipulate.
  • Lungs: necessary to capture oxygen from the air and be able to carry it, through the circulatory system, to the cells.
    • Amphibians: their lungs are rudimentary, they need cutaneous respiration as a complement.
    • Birds and mammals: their lungs are more evolved.
  • Reproduction.
    • Amphibians: It is the group worst adapted to life on land. Their fertilization is external, they lay eggs in the water and the young cannot leave the water until they become adults.
    • The rest of tetrapods have sexual reproduction with internal fertilization:
      • Reptiles and birds are oviparousThe bone has a hard shell and a protective bag, the amnion, filled with a liquid that protects and isolates the embryo. Normally, the mother deposits the eggs and the embryo does not come out until it is already developed. In some cases, they are ovoviviparous, and the eggs remain inside the mother until the young hatch.
  • Mammals, except for the platypus, are viviparousThe embryo is not protected by an egg, but instead develops in the mother's womb and is nourished through the umbilical cord (except in marsupials). When they are born, they feed on mother's milk.

The horse and the chicken

You already know that horses are herbivores... almost always. Do you want to see what a horse did with a chick?