Question

what are the main differences and adaptation productively between eutherian mammals and marsupial mammals?

explain how homoplasy and ecotype intersect at the ordinal level?

Answer 1

DIFFERENCE BETWEEN EUTHERIAN AND MARSUPIAL MAMMALS-

Mammals are divided into three groups based on how their babies develop. These are placental, marsupial and monotreme mammals.The most important characteristic of all mammals is that they feed their babies milk from their mother's body. Hence the name "mammal" derived from the Latin word mamma which means teat or nipple. Mammals also breathe air, have backbones, are warm-blooded, have a four chambered heart and have fur or hair. The young of most, but not all, mammals are born alive.

Some of the main differences between eutherian and marsupial mammals are as follows-

a)Placental mammals constitute over 5,000 different species of animals and include those as varied as humans, aardvarks, cats, horses and even whales while Marsupial mammals constitute 334 species of mammals and include animals such as kangaroos, koalas, possums and bandicoots.

b)Another key difference is that in a placental mammal the baby remains attached to the placenta inside the mother's uterus for a relatively longer period of time compared to a marsupial.

c)Placental mammals provide nourishment for their young by providing them with milk through teats or nipples. Because the baby is already relatively well developed before it is born, the period of lactation is much shorter than for equivalent marsupial and monotreme mammals.

d)The basal metabolic rates (BMRs) of placental mammals is about 30% higher than marsupial and monotreme mammals. This means they consume far more energy than an equivalent sized marsupial or monotreme.

e)Marsupials, in general, have more teeth than placental mammals. They also grow only one set of teeth of which some are replaced during their lifetime. (They have no milk teeth).