Which of the following is the correct definition of classification? (A) Classification is the organization of living things into groups that have similar
features. (B) Classification is the organization of living things into groups that have
different features. (C) Classification is the organization of dead things into groups that have similar
features. (D) Classification is the organization of organisms into large, mixed groups. Or (E) classification is the organization of organisms into groups that inhabit the
To help us answer this question, let’s first understand what classification is.
Scientists classify living organisms into groups to make them easier to study and to
allow information on organisms to be shared efficiently. Initially, scientists classified organisms based purely on the physical
characteristics they could observe. As science and technology advanced, biologists began to classify organisms based on
physical characteristics and their genetic and evolutionary relationships. This was made possible by advancements in DNA technology and genome sequencing.
So when scientists classify living organisms, they are organizing them into groups
based on meaningful similarities. For instance, all organisms classified into the animal kingdom are multicellular. They are also heterotrophic, which means they have to consume other organisms for
A kingdom is a very large group, which includes organisms from tiny worms to the huge
blue whale. So scientists will divide these large groups into more specific smaller
subgroups. For instance, the chordate phylum is a subgroup of the animal kingdom, which only
contains animals that possess a notochord at some stage in their development.
Each subgroup provides additional information about the species that are contained
within it. For instance, class Mammalia only includes the chordates that give birth to live
young, like humans.
The key aspect of this method of classification is that each group is unified by
similar characteristics, which get more specific as the groups get smaller. So for our correct definition of classification, we are looking for a mention of
living organisms being classified into groups that share similar characteristics or
From this information, we can see that option (A) is correct. Classification is the organization of living things into groups that have similar