HOW TO CLASSIFY? Read the passage and answer the questions which follow.
It has been suggested that only 1 in 10 of the plant and animal species in the world have been
described and classified. Hundreds, and sometimes thousands, of new species are discovered and
described every year.
When a new organism is discovered, it is given a binomial. Taxonomists attempt to describe its
morphological characteristics, so that other biologists will be able to recognize it, and distinguish
it from other similar organisms. Further studies, however, may be required before it can finally
be decided whether the organism is a truly new species, or simply a morphological variant of a
species which is already known and named.
A large majority of known species, and of the new ones being discovered, are insects. Of these,
the beetles make up by far the largest group; one on four of all known species are beetles. In one
study in a Panamanian rain forest, it was found that nine individuals of the tree Luehea
seemannii had 1200 species of beetles living on them, of which 163 species were estimated to be
found only on that species of tree. As the number of tropical rain forest species is about 50,000,
it was calculated that there could be 8,150,000 different species of beetles found on those trees.
Simply describing large numbers of species would produce an unmanageable list. To handle such
large quantities of data, taxonomists must classify species. The earliest systems of classification
were artificial. Plants, for example, can be classified as edible, medicinal or poisonous. Modern
classification systems now attempt to classify organisms in a hierarchical, phylogenetic manner.
1. Define the following terms:
a. binomial (line 4);
Having two names; used of the system by which every animal and plant receives two names, the one
indicating the genus, the other the species, to which it
…………………………………………………………………………………………
……………
belongs.
b. hierarchical (line 18);
It is a group of animals or species that are organized into ranks or
grades.………………………………………………………………………………………………
………
………………………………………………………………………………………………………
1
5
10
15
2. When a new organism is discovered, further studies may be required before it can finally be
decided if it is a new species. Suggest what these studies might be. (Line 6)
These studies might be to test if it is indeed a new species or simply a morphological variant of a
species. The tests might be some genetic tests.
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
3. In what way is a phylogenetic classification system better than an artificial one?
It gives more information that an artificial one and also the plant identification are much easier.
It can be changed as knowledge is collected.
4. In the Panamanian rain forest study, what assumptions have been made in calculating that
there may be 8,150,000 different species of beetles living on rain forest trees? (Lines 13-14)
That only in one tree alone, 163 species where found. There many species in one tree and there
is the same in any other trees.
……………………………………………………………………………
…………………………
b. Suggest one way in which this study could realistically be extended to give a more
reliable estimate of the number of beetle species in the rain forest.
One way would be to get more data instead of estimating it.
……………………………………………………………………………
…………………………