amphibians

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29 05, 2017

Eggs – Evolution and Biology

By |2019-05-24T11:37:23-07:00May 29th, 2017|Biology|0 Comments

Fish eggs: Egg evolution starts with soft eggs like these When did the first eggs evolve? The earliest living creatures made babies by dividing themselves in half, so that one cell became two cells. But about 1.4 billion years ago, some creatures with more than one cell began to develop specialized cells. These [...]

26 05, 2017

What are intestines? Evolution and Digestion

By |2019-09-21T15:05:41-07:00May 26th, 2017|Biology|0 Comments

Whale intestines (from Medicine Chest) When did intestines evolve? The first animals to have anything like an intestine evolved around 548 million years ago. These were roundworms, just a few millimeters long. Roundworms had just a simple tube running from their mouth to their anus - no stomach in the middle. What's a [...]