Switching to phylogenetics
The system of phylogenetic classification works differently than the traditional system.
- Looking at rank
Phylogenetic
classification has two main advantages over the Linnaean system. First, phylogenetic
classification tells you something important about the organism: its evolutionary history.
Second, phylogenetic classification does not attempt to "rank" organisms. On the other
hand, the Linnaean classification "ranks" groups of organisms artificially into kingdoms,
phyla, orders, etc. This can be misleading as it seems to suggest, for example, that a cat
family is somehow comparable to an orchid family. However, they are not comparable:
- One may have a longer history than the other. The first representatives of the cat family Felidae
probably lived about 30 million years ago, while the first orchids may have lived more
than 100 million years ago.
- They may have a different level of diversity. There are about 35 cat species and 20,000
orchid species.
- They may have different degrees of biological differentiation. Many orchids belonging
to different genera are able to hybridize. But the same is not true of cats — house cats
(belonging to the genus Felis) and lions (belonging to the genus Panthera) cannot
form hybrids.
| Orchids of these two different genera hybridize... |
 |
...but cats of these two different genera do not. |
 |
 |
 |
 |
 |
 |
| Laelia |
|
Cattleya |
Felis |
|
Panthera |
There is just no reason to think that any two identically ranked groups are comparable
and by suggesting that they are, the Linnaean system is misleading. |
