Monotremes include the duck-billed platypus and the spiny echidna, both of which
ID: 272250 • Letter: M
Question
Monotremes include the duck-billed platypus and the spiny echidna, both of which are mammals, but lay eggs. Explain why these animals are considered mammals and give a possible explanation of why there are not more egg laying mammals. ps/assessment/take/launch.jsp m Take Test barn 4 Animas-x (L) e O a four-chambered heart O the ability to maintain a constant body temperature O two pairs of appendages the shelled, amniotic egg QUESTION 5 Monotremes include the duck-billed platypus a and give a possible explanation of why there are not more egg-laying mammals. Wite in your nd the spiny echidna, both of which are mammals, but lay eggs. Explain why these animals are considered mamma own words. Copying from any source will receive no points T TT Arial 3( Woids Path QUESTION 6 heen lost E eyglred independently an essay explaining the difference between "secondary loss" and independent evolution of traits Give at leastExplanation / Answer
The chief characteristics of mammals are: warm blooded (endothermic), presence of mammary glands, presence of four limbs, fur, sweat glands in skin, alveoli in lungs, a four chambered heart, a brain covering called as neocortex, have four different types of teeth
Monotremes are endothermic (warm blooded) animals, have mammary glands to feed their young, have fur. Eventhough they lay eggs, they carry them in the pouch of their bodies until they are hatched. So, by definition, from these basic fundamental characteristics they share with mammals, they can be classified as mammals. This can also be proved from their phylogeny. They are considered as mammals because they have a evolutionary lineage which branced off from mammals (over two hundred million years ago) and thus they are called as primitive mammals.