Classification of OrganismsIn Kingdom Animalia

StructureFunctionGeneticsEmbryology

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 partEx: insects, spiders

•Non-Segmented: No Division of animal parts.Ex: humans, dogs, cats, lions, etc.

C. SYMMETRY

1. 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. SYMMETRY3. 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. Exoskeleton1. “ENDO” – inside, meaning the

skeleton is found inside of the body.

Ex: humans and dogs

2. “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. CoelomCoelom – 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 identificationExamples:

•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. GENETICSEvolutionary 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. EmbryologyEMBRYOLOGY – 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!