The 500 Million Year History of Vertebrates

This creature was one of the earliest amniotes.

Some tetrapods soon evolved the ability to lay water-tight eggs, making them amniotes. This adaptation allowed them to lay eggs on land instead of in the water. Along with water-tight skin, this adaptation helped animals live on land entirely.

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The adaptation of water-tight eggs allowed amniotes to lay their eggs on land instead of in the water. How do you think this helped them survive better?

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I wonder if the eggs were in any danger in the water.

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Predators sometimes eat other animals' eggs. On land, there were fewer predators to hunt and eat the eggs than in the water.

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