Erythropoiesis (from Greek 'erythro' meaning red and 'poiesis' meaning to make) is the process which produces red blood cells (erythrocytes).
Birds and mammals have the following characteristics in common: they are vertebrates, meaning they have an internal skeletonthey are warm-bloodedthey breathe using lungs, so â¦ have full respiratory systems they have circulatory systems. Most mammals give live birth, but there is a sub-group known as monotremes, which are the egg-laying mammals. 2  This group includes just the platypus and the echidna. 3  They are still mammals because, like all mammals, they feed their young on mothers' milk.
Hair is common among mammals and can take many forms, including whiskers, spines and fur. All mammals breathe air, so even those living in water must surface to take a breath. Two types of mammalsâthe platypus and the echidnasâlay eggs, but all others give birth to live babies. Like birds, all mammals are warm-blooded.