One small step: There have been a number of dramatic transitions over the history of life. After a few billion years of nothing but single-celled organisms, multicellular life developed. Organisms evolved tissues and organs. Plants developed spores, flowers, and seeds. Animals developed complex neurological systems and external and internal skeletons. And, of course, bacteria evolved novel methods to live just about everywhere on Earth.One of these great transitions is the subject of this level. Have you ever heard of an animal called Tiktaalik? How about Acanthostega? They are but two of the many remarkable fossils we have that document the transition of animal life from water to land. Answer questions below before you move on to the next level, “Origin of whales.”1.For an animal that lives in shallow water, what is the advantage of having eyes on the top of itshead?2.We know that Tiktaalik is more closely related to Acanthostega than it is to EusthenopteronbecauseTiktaalik and Acanthostega:a.Both lackeddigitsb.Both lacked strong forearmsc.Both had a humerus, radius, andulnad.Both had eyes on the top of theirheads
