Page 87 - Biology_F5

Biology for Advanced Level Secondary Schools

Phyletic classification was followed grouping animals as flying and non-flying
by phenetic approach. Phenetics uses animals, edible and non-edible plants, spice
many characteristics and mathematical and non-spice plants, predators and preys,
alogarithms to group similar organisms
in same cluster and different organisms in as well as medicinal and non-medicinal
different clusters. As in natural system, plants. As noted from the above examples,
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phenetics does not consider evolutionary this system of classification neglects natural
history. The most recent approach is known relationship existing among the groups of
as phylogenetics. This approach brings organisms. For instance, both birds and
together organisms that share derived bats are flying animals, but the former
characters into groups called clades. Thus,
clades are made up of organisms that share have feathers while the latter have hairs
the most recent ancestor. and mammary glands. Similarly, medicinal
plants that produce flowers, seeds, and
The change from one approach to the next fruits are different from spore producing
was influenced by advances in science and
technology, leading to the use of new source medicinal plants. Thus, the medicinal value
of taxonomic data, methods of analysis and attached to these plants cannot suffice their
weaknesses observed in previous approach. placement in one group because they have
Phylogenetic approach use DNA markers, no shared natural features. This limits the
different computer software and analysis application of this classification system
programs.
despite its significant merits. Artificial

Types of classification systems system cannot group individuals that are
In this book, only two major systems evolutionarily related. As a result, all

of classification, namely artificial and classfication systems that do not reflect
natural systems of classification, will be evolutionary history are considered to be
discussed in detail. artificial.

Artificial system of classification Merits of artificial system of
This system of classification uses a few classification
easily observable characteristics to classify (a) It is simple to identify and classify
organisms for easy and quick comparison organisms since newly discovered
and study. Examples of artificial organisms with just a few known
classification could be when grouping all information can be easily fitted in. It
animals as fauna and all plants as flora, or therefore takes short time in placing an
when grouping all organisms on the basis organism into its group.

of their body size, as microorganisms and (b) It is stable, as it does not change with
macroorganisms. Other examples are when time or discovery of new knowledge.

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