ANATOMY

Detailed explanation-1: -Common descent is an effect of speciation, in which multiple species derive from a single ancestral population. The more recent the ancestral population two species have in common, the more closely are they related.

Detailed explanation-2: -common ancestor: The most recent ancestral form or species from which two different species evolved.

Detailed explanation-3: -In genetic genealogy, the most recent common ancestor (MRCA) of any set of individuals is the most recent individual from which all the people in the group are directly descended. The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree.

Detailed explanation-4: -If two or more species share a unique physical feature, such as a complex bone structure or a body plan, they may all have inherited this feature from a common ancestor. Physical features shared due to evolutionary history (a common ancestor) are said to be homologous.

Detailed explanation-5: -Hippos and whales may look different in many ways, but they are actually each others’ closest living relatives-sharing a common ancestor that lived about 55 million years ago.