Video Transcript
Why is it difficult to classify
viruses into Whittaker’s system of classification? (A) Because they have very few
defining features. (B) Because they are generally
considered to be nonliving. (C) Because Whittaker’s system did
not include classification of microorganisms. (D) Because they were discovered
after Whittaker created his system of classification. Or (E) because they share
characteristics with both kingdom Plantae and kingdom Fungi.
Whittaker’s five kingdoms are
Monera, Protista, Fungi, Plantae, and Animalia. These kingdoms only group together
living organisms. But that includes microscopic
organisms of just a single cell, like, for example, the prokaryotic bacteria found
in Monera, as well as complex multicellular organisms, like you or me.
Scientists generally consider
something to be a living organism only if it consists of one or more cells. A virus is basically a sac of
proteins that surround a collection of genetic material. Viruses don’t have cells or a
metabolism for extracting and using energy for growth or maintaining
homeostasis.
In order to reproduce, a virus
inserts its genetic material into a living cell and thereby forces the cell to
produce more copies of the virus. A virus therefore needs a host cell
in order to reproduce and cannot reproduce on its own. So, viruses don’t meet all of the
typical criteria for life and, as a result, are generally considered to be
nonliving.
Therefore, the correct answer to
this question is (B). It is difficult to classify viruses
into Whittaker’s system of classification because they are generally considered to
be nonliving.
