Classification of Organisms In Kingdom Animalia

Structure Function Genetics Embryology Organisms are Classified in 4 Major Ways:

A. APPENDAGES - Structures that extend from the core of the body. Ex: legs, antennae, arms, fins, wings, flippers, etc. Structure

B. Segmentation Segmented: Clearly differentiated subdivision of an organism or part Ex: insects, spiders Non-Segmented: No Division of animal parts. Ex: humans, dogs, cats, lions, etc.

C. SYMMETRY  Asymmetrical: No definite shape or form. No halves look alike Ex: Sea Sponge

C. SYMMETRY 2. Radial: Appendages extend from a central axis. Ex: Starfish

C. SYMMETRY 3. Bilateral Symmetry: Animals with right and left sides. “Mirror images” Ex: Humans, crabs, etc.

D. Cephalization Cephalization: Concentration of sensory and neural organs toward the front of the head. Ex: Your eyes, ears, nose, and mouth are located around the head region.

E. Endoskeleton vs. Exoskeleton  “ENDO” – inside, meaning the skeleton is found inside of the body. Ex: humans and dogs  “EXO” – outside, meaning an external covering that provides protection and support EX: insects, arthropods, armadillos

F. Sessile vs. Non-Sessile Sessile – An organism is permanently attached to a solid object at its base. Ex: sponge, sea anemone

G. Body Covering Scales Skin Feathers Fur Hair

H. Coelom Coelom – A CAVITY formed within the mesoderm. Acoelomate – without a coelom Ex: sponges, flatworms Pseudocoelmate – “False” coelom. Cavity lined with mesoderm and endoderm. Ex: roundworms Coelomate – Cavity with 3 germ layers that allows organs to be attached. Ex: earthworms, molluscs, humans

I. Body System Internal Systems are good for identification Examples: Human stomach vs. cow (“ruminant”) Solid vs. hollow bones

II. FUNCTION What is the function of the organism? Predator or Prey? Herbivore? Carnivore? Omnivore?

III. GENETICS Evolutionary history can help us group organisms. Every organism has certain body proteins and sequences of DNA. Ex: If you are examining two bird species, you can determine relationships by comparing proteins found in the egg whites.

IV. Embryology EMBRYOLOGY – Branch of biology concerned with the development of an organism. Embryo development is life’s building program. A few cells duplicate, grow, and specialize over time into a complex organism made of MANY cells!