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.
1 Wings: Wings are one of the most defining characteristics of birds, and even flightless birds have vestigial or adapted wings they may use for swimming, threat displays or courtship dances. The size and shape of wings varies between species based on how the bird flies, and wing markings are useful to identify bird species. 2  Bill: All birds have a bony, keratin-covered projection forming their mouth.