Question

If you were presented with a phylogenetic tree, how would you go about identifying a clade on the tree? Make sure to use the terms “node” and “branch” in your answer. In most phylogenetic trees, is there a single clade (monophyletic group) or more than one? Explain.

Defend the claim that prokaryotes dominate most nutrient cycles on Earth.

Answer 1

Monophyletic group is the one which includes an ancestor and all of its descendants. We call it as a clade because all the descendants have been derived from the same common ancestor by showing different mutation or evolution of different characters.

The common ancestor in a monophyletic group is represented by a node and all the branches represent speciation event. The tips of all the branches represent descendants of the common ancestor.

It is not necessary that a phylogenetic tree will contain a single monophyletic group. There can be more than one monophyletic group and there are chances that the monophyletic groups are overlapping.

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