TAXONOMY

 



Biologists have for centuries recognized that the shapes or morphologies of organisms tend to cluster or clump around certain basic groundplans. For example, "cat" can be used to describe a particular species of domesticated animal (Felis gattus) or a more inclusive group of animals that look more or less like F. gattus, for example F. concolor (mountain lions), Panthera leo (lions) or P. tigris (tigers). The pattern of differences among individual species of organisms, coupled with the similarities at various levels, led Linnaeus to construct a classification scheme that recognized both aspects of organic diversity. Individual species were recognized and granted a binomen (two part name) like Felis gattus. Very similar species were included in the same 'genus', for example Felis concolor is placed very close to F. gattus. More distinct species are assigned to different genera (like Panthera) but are included in the same 'family' - in this case the 'Felidae'. Cats and dogs may not, at first glance, look much alike, but compare them with elephants or whales, and it is clear that there are some similarities (like their teeth) that suggest their relationship. They, as well as bears, racoons, hyenas, etc. are placed in a more inclusive category (an 'order') called the Carnivora. The Carnivora might seem totally unlike whales or rabbits, but when compared with a snake, fish, or toad, their hair, warm-bloodedness, live birth, and milk production suggest otherwise. All animals with these attributes (and others) are grouped in a large category ('class') called the Mammalia. Mammals, reptiles, birds, amphibia, and fish all have a nerve chord along their backs, and so are assigned to a higher level category ('phylum') called the Chordata. A chordate (such as a human) and a sand dollar may not look much alike, but if we compare them to a tree, the need to find and eat food clearly suggests a relationship that they do not share with the plant. All organisms that seek food and ingest it belong in a final, most inclusive category ('kingdom') called the Animalia.

The levels of similarity are emphasized in the classification by their hierarchical arrangement. From most to least inclusive these are:



KINGDOM

-----PHYLUM (plural = PHYLA)

----------CLASS

---------------ORDER

--------------------FAMILY

-------------------------GENUS (plural = GENERA)

------------------------------SPECIES

 

A house cat "belongs to" or is a member of the species Felis gattus. It also belongs to the genus Felis, the Family Felidae, the Order Carnivora, the Class Mammalia, the Phylum Chordata, and the Kingdom Animalia. Humans belong to the species Homo sapiens, the genus Homo, the Family Hominidae, the Order Primates, and from there we share our relationships with the cats: Class Mammalia, Phylum Chordata, and Kingdom Animalia.

Body fossils, as the remains of past life, suggest at least two things of biological importance:

1) They provide a time dimension to the similarities described above by letting us project the relationships backward through time.

2) They show us additional morphological diversity that does not presently exist in the living world, but that was clearly possible in the geologic past.

Both these things provide insights into the processes and patterns of organic evolution that the Recent world does not afford.

The following page is simply a list of the fossil taxa of southwest Georgia tabulated so far in this webpage, along with links to show you what each species looks like.



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