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Biological Environment > Amphibians |
Earth Earlier Earlier 350 Million Years ago Later Earth After Animals Later |
This site tells the story of the history of the universe. Click Earlier and Later to follow the story. Note: Many facts have been simplified to make them easier to understand. |
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Once the plants and arthropods were living on land there was plenty of food for any vertebrate which could manage to come out of the water. Some fish lived in ponds which dried up in summer. Their swim bladders evolved into lungs which they used to breathe air. They used their fins to crawl from one pond to another and these evolved into legs, two at the front and two at the back.
The vertebrates which emerged from the water and became land animals around 350 million years ago we call amphibians "am-fib-ee-ans". Their name means "both lives" because they lived both in water and on land at different times in their lives.
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![]() | Amphibians were still not totally free from the water. They needed to return to it to reproduce (like the ferns and the arthropods before them). Their eggs were laid and fertilized in water and the young developed in the water just like their fish ancestors. But when amphibians grew up they left the water to live on the land. Most frogs and newts are still at this stage of evolution. | |
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Earth Earlier Earlier 350 Million Years ago Later Earth After Animals Later |
Biological Environment > Amphibians |
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Basic Information |
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