Answer: What makes a marsupial, a marsupial? A discussion on the historical biogeography and biological evolution of marsupial mammals. Dr. Robert Voss is a professor at Richard Gilder Graduate School and the American Museum of Natural History. His primary research interests are the evolution of marsupials and the systematics and biogeography of other Neotropical mammals that inhabit moist-forest habitats in Amazonia and the Andes.
What anatomical characteristics distinguish marsupial mammals from placental?
Living marsupials and placentals can be distinguished by a number of anatomical features, including structural differences in their ear regions, teeth, postcranial skeletons, reproductive tracts, and brains. Most people think of pouches when they think about marsupials, but not all marsupials have pouches.
When did these two subclasses of mammals separate from their common ancestor? What do we know about that common ancestor?
The lineages that gave rise to living marsupials and placentals are recognizably distinct in the fossil record as far back as the Early Cretaceous (about 125 million years ago), so the most recent common ancestor of these groups must have lived even earlier. How much earlier is controversial, with some estimates suggesting a date of almost 150 million years (in the Late Jurassic). We don’t know anything about that ancestor for certain, but we assume that it was not unlike the earliest known marsupials and placentals: probably a small climbing (arboreal or semiarboreal) mammal, perhaps superficially resembling living opossums or tree shrews. Because the earliest known marsupial and placental fossils are from China, most paleontologists assume that their most recent common ancestor lived somewhere in eastern Asia.
What is convergent evolution and what are some examples of convergent evolution between marsupial and placental mammals?
Convergent evolution is the appearance of similar traits in distantly related lineages. Examples of convergent evolution between placentals and marsupials are the extinct Tasmanian “wolf” (a very wolflike marsupial), marsupial “moles” (living molelike marsupials that burrow in the sandy deserts of Australia), and kangaroo rats (North American rodents that hop on their hind legs like kangaroos).
Explanation:
Answer:
A) incomplete dominance.
Explanation:
It is a clear case of incomplete dominance. This kind of inheritance shows deviation from Mendel's popular law of genetics which is known as "Law of Dominance". This law states that when two pure breeding parents i.e. homozygous dominant and homozygous recessive are mated then all their off-springs are genotypically heterozygous but phenotypically they all show dominant trait. But in incomplete dominance, <u>the dominant allele is unable to mask the expression of recessive allele completely</u> which leads to a phenotype which is a blend of both the traits.
In the example, orange beak is unable to mask the expression of ivory beak completely as a result of which all the off-springs have an intermediate trait which is pale, ivory-orange beak.
Answer:
Of these, there are six main elements that are the fundamental building blocks of life. They are, in order of least to most common: sulfur, phosphorous, oxygen, nitrogen, carbon, and hydrogen.
Explanation:
There is a messy and water is everywhere.
Explanation:
Metals and the frequency in which they're found influences a lot since different metals have different densities. Heat also influences a lot since hotter things tend to be less dense though the inner core is more dense.
Answer:
The inner core is more dense because it's liquid and hotter, and since it's liquid the earth's movement makes it difficult for the inner core to be less denser than it is.
Hope it helped,
BioTeacher101
