Similarities between marsupials and placental mammals? (Details inside!)?
I'm doing an AP Bio assignment and need to fill in a ven diagram. I have most of the circles filled in aside from three.
-Similarities between marsupials and placental mammals
-Similarities between marsupials and monotremes
-Similarities between monotremes and placental mammals
PLEASE not differences. The only things I can find online are differences. I need similarities.
Update:Thank you, that was actually very helpful.
Now we just need to fill in the last circle/ Monotremes and placentals.
Answers & Comments
Verified answer
Most of those would come under the categories of features common to all mammals, such as fur and production of milk, pentadactyle limbs, etc
common between marsupials and placentals is that they are viviparous (give birth to live young, rather than laying eggs which is what the monotremes do)
common between marsupials and monotremes is that they lack a placenta
EDIT: monotremes and placentals are the most difficult because they are the furthest separated on an evolutionary timeline: there is nothing I can think of that is common to both that doesn't also feature in the marsupials. In a Venn diagram it is perfectly possible to have an empty set.
Therian > was once the last original ancestor a monotreme? The Therians are placed in a single clade, because of this taxonomists consider the marsupials and placentals branched off an animal that gave are living beginning. Wikipedia seems to location placentals before marsupials (160Mya versus 125Mya), which might point out that the long-established ancestors would were placentals.