CLASSIFICATION OF ANIMALIA

Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. Scientific classification also can be called scientific taxonomy. TAXONOMY is the practice and science of classification. A TAXON (plural taxa) is a name designating an organism or group of organisms according to presumptive evolutionary (phylogenetic) relationships.

The seven main Taxa are, from largest to smallest:

KINGDOM, PHYLUM or DIVISION (botany), CLASS, ORDER, FAMILY, GENUS, SPECIES

KINGDOM: ANIMALIA

PHYLUM: ARTHROPODA

CLASS: INSECTA

ORDER: HYMENOPTERA

FAMILY: APIDEA

GENUS: Apis

SPECIES: Apis melifera

Each species name is in Latin (scientific name) and has two parts: the genus name (in the example: Apis) and a second word identifying the species within that genus (mellifera).
Species names are usually typeset in italics. Also they may be underlined.
The genus name is always written with an initial capital letter and the specific name is never written with an initial capital.

INVERTEBRATES and VERTEBRATES

About 97% of all animals on the Earth are invertebrates. Invertebrates are any animal without a spinal column (endoskeleton). Although it is very common to separate thus the animals, this way of classification is not very correct because it classifies the animals between those that look like us (we are vertebrates and we have an spinal column), and those that do not like us (invertebrates).

However, it is used frecuently.

Characteristics of invertebrates Simplest animals Contains the greatest number of animal species Most found in water Do not have an backbone (spine column: endoskeleton). Some species have an exoskeleton (Molluscs, Echinoderms) and other have no skeleton (Annelids) Includes sponges, cnidarians, flatworms, roundworms, annelids (segmented worms), molluscs, arthropods, and echinoderms

Body Symmetry is the arrangement of body parts around a central plane or axis

Asymmetry: when the body can't be divided into similar sections (Porifera)

Radial symmetry: if the body parts are arranged around a central point like spokes on a wheel (Echinoderms). Most animals with radial symmetry are sessile (attached) or sedentary (move very little)

Bilateral symmetry: if the animals can be divided into equal halves along a single plane (right and left sides that are mirror images). Animals with bilateral symmetry are more complex, usually motile organisms, such as worms, arthropods, and all vertebrates. Animals with bilateral symmetry show cephalization (we are animals with bilateral symmetry)