Today, Earth is home to animals of all shapes ... probably had little or no recognizable pattern. Related: What were the first animals to have sex? Turner presented what she proposes as the ...

Fossil evidence reveals that molluscs may have been among the first animals to spend time out of the water, overturning the popular theory that arthropods were the undisputed early land pioneers. The ...

The first life forms to appear on Earth were unicellular, i.e. composed of a single cell, such as yeast or bacteria. Later, animals -- multicellular organisms -- evolved, developing from a single ...