General Flashcards
1
Q
Metazoa
A
Animals can be further subdivided into two branches. The Choanozoa are unicellular aquatic protists that sometimes form colonies. The rest of the animals – including fish, birds, amphibians, reptiles and mammals – are all multicellular and are collectively referred to as the Metazoa. Metazoa are considered monophyletic, meaning that all organisms developed from a common ancestral form. As a group, they show an evolution from multicelled organisms acting more like colonies with quasi-independent cells, to more highly developed animals in which cells cooperate to form tightly coordinated tissues and organs.
