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Zoologists, who study animals, estimate that
there are over four million animal species live on earth. All
these animals are divided into 35 or more phyla according to their body
plan, similarities and evolutionary relationships. Click on animal
tree and view the evolutionary relationship among the nine phyla of
the animal kingdom.
Zoologists divide all these animals
into two major subphyla. Subphylum Invertebrata (invertebrates)
animals with no bones. All invertebrates make up more than 95% of
all animal species. The vast majority of invertebrates are
insects, snails, jellyfish, and worms.
Subphylum Vertebrata
(vertebrates) animals with back bones. Vertebrates such as fish,
frogs, snakes, birds, and mammals make up less than 5% of all animals on
earth.
The classification hierarchy today is
recognized from the least inclusive to the most inclusive or vise versa as the following:
species grouped into genera
(genus - singular), genera into families, families into orders, orders
into classes, classes into phyla (phylum - singular), phyla
into kingdoms, kingdoms into domains (domain = a taxonomic
level higher than kingdom).
There are three domains Eubacteria
(true bacteria), Archaebacteria (ancient bacteria), and the
domain Eukarya.
The kingdoms Eubacteria and
Archaebacteria belong to domains Eubacteria and Archaebacteria
respectively.
The kingdoms Protista (most
members are single cell organisms such as ameoba), Fungi (most
members are multicellular such as mushrooms), Plantae (all are
multicellular and photosynthetic), and Animalia (all members are
multicellular and heterotrophic) belong to the domain Eukarya.
Let's
classify ourselves!
We are the members of the domain Eukarya, the
Kingdom Animalia, the phylum Chordata, the class Mammalia,
the order Primate, the family Hominidae, the genus Homo,
and the species sapiens.
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