Evolution
Reptile and Amphibian evolution:
Fish develop lungs and walk on land: 390 million years ago
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The lop-finned fish called a Crossopterygian and the lung fish called Dipnoans were the first fishes to develop lungs. Through evolution, the Crossopterygians were the ancestors of land animals. They developed land animal-like features. The Eusthenopteron was one type of Crossopterygian and was one of the first fish to venture out onto land. Some reasons for this occurring was because they had to find a new food source, and when their pond dried out from a drought they had to cross over land to find a new pond.
Amphibians became adapted to life on land: 300-250 million years ago​
Amphibians began to evolve with different features which include:
- Bigger nostrils for breathing air
- Evolve hands and feet
- Tale size decreased
- Backbones grew stronger

The Eryops which is a type of amphibian, evolved and had an incredibly strong skeleton with toughened scales to protect itself from predators. They usually fed on fish and very few land living animals.
Reptiles begin to take over: 325 million years ago​
During this time, oceans were retrieving backwards causing competition for survival in the seas. This increased the number of reptiles.
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Advantages that reptiles have over amphibians:
​- More freedom from water
- A reptile's skin is thick and tough
- Stronger limbs
- There is no worry of the eggs being washed away because its on land​
Amphibians start to evolve into reptiles: 325- 250 million years ago
The connecting link between reptiles and amphibians is an animal called a Seymouria which lived during the Permian times. The Seymouria's skull was similar to an amphibian. However, it resembled a reptiles through it skeleton structure. It also had rough, over lapping scales.

Animals that lived in shallow water evolved lungs and scales. Following this, they developed legs, shelled eggs and the capability of breathing through their nostrils with their mouths closed. Shelled eggs have a huge advantage because it will not dry out when outside of water.
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Eusthenopteron
Eryops
Seymouria