Question

What are some examples of polyphyletic organisms?

Answer 1

A polyphyletic group is a group whose most recent ancestor does not have the same characteristic features as the group.
Polyphyletic classification has the purpose of grouping together species such that they have the same common ancestor.

Complete answer:
Polyphyly is a term that describes a group of organisms whose last common ancestor is not a member of the group i.e. the last common ancestor has different characteristics as the group.
A polyphyletic group of organisms is a series of organisms that have been grouped together with respect to the characteristics of these organisms that do not imply that these organisms share a common ancestor that is also not a common ancestor of other taxa.
Reptiles are an example of polyphyletic organisms. A crocodile has more common characteristics with a lizard than a bird and both lizards and crocodiles are classed as reptiles. However, crocodiles share more recent common ancestors with birds than with lizards.
Birds and mammals may share some physiological and biochemical characteristics. However, the most recent common ancestor of birds was cold-blooded which means that birds developed the characteristic of warm-blood independently.
Flying vertebrates are a polyphyletic group as it includes bats and birds but their most recent common ancestor was a non-flying animal such as a primate.
Photosynthetic organisms are polyphyletic as there are plants and bacteria present in the group and their nearest common ancestor may include non-photosynthetic organisms.

Note:
Polyphyly is a term used in the field of cladistics. Polyphyly describes a group of organisms whose previous common ancestor is not a member of the same group i.e. the ancestor has differing characteristics when compared to the group. Polyphyly can also be expressed by saying that it includes groups in which a few members have descended from an ancestral population.
A few examples of polyphyletic groups are:
-Warm-blooded birds and mammals
-Elephants, Hippopotamuses, Rhinoceroses
-Anteaters and protozoans
-Flying vertebrates
-Photosynthetic organisms