Definition of float in the AudioEnglish.org Dictionary. Meaning of float. What does float mean? Proper usage and pronunciation (in phonetic transcription) of the word float. Information about float in the AudioEnglish.org dictionary, synonyms and antonyms.
Mammals evolved from a group of mammal-like reptiles called the Synapsids, specifically the Therapsids, in the Triassic period, around 250 million years ago.
Through time three major groups of mammals evolved: Prototherians - lay eggs (eg. platypuses and echidnas) Metatherians - young develop in pouches (marsupials such as kangaroos and koalas) Eutherians - give birth to well-developed offspring (includes many familiar species such as rabbits, elephants, horses, and humans) The platypus is a prototherian.