Question

Explain the challenges the vertebrates faced in moving from water onto land, and give a ‘solution’ or response to each challenge that can be seen in modern reptiles.

Answer 1

The main problems faced by the vertebrates in moving from water to land was weight and structural support and not breathing problem. In marine conditions, organisms are buoyed by the water and it is considered thier body weight to be zero. But, in land the body is held up by skelton and limbs. Other factors included locomotion, water balance, sensory system, feeding and reproduction.

But, the tricky transition happened in the modern reptiles that helped them to survive in the land. The main factor was the physical change, which included skeletal modifications, such as addition of ribs & development of interlocking vertebrae.

Also, seperation of skull and pectoral girdle favored modern reptiles to absorb shock generated during movement.

Loss of water was overcomed by development of waxy substance through glands, water tight skin or by the inhabitation of moist habitats.

Development of lungs from gills helped them to intake oxygen which ultimately developed thier breathing system. Finally, sensory organs where adjusted, for instance - modification in the anatomy of ear and eyes helped them to adjust the variations in sound and light transmission.