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.
Monotremes have an unusually complex sex chromosome system which shares extensive homology to bird sex chromosomes and no homology to sex chromosomes in other mammals. This has entirely changed the way we think about the evolution of sex chromosomes in mammals as it suggests that birds and early mammals shared the sex chromosomes which evolved in the reptilian common ancestor.