Cells demonstrate division of labor but are not strongly associated to perform a specific collective function.
Two distinct tissue layers derived from embryonic germ layers. Ectoderm and Endoderm.
Three tissue layers assembled into larger functional units called organs. Ectoderm, mesoderm, and endoderm
No body cavity. After blastula formation, cells reorganize to form adult body.
Central Body Cavity. Mesodermal cells line the outer edge of the blastocoel. False body cavity (only partially lined with mesoderm)
Central Body Cavity. Called a coelom. True body cavity (completely lined by mesoderm)
Serial repetition of a similar body segments along longitudinal axis of body. Annelids, Arthropods, Chordates
Permits greater body mobility and complexity of structure and function
Any plane passing through the center divides the body into mirrored halves. Best suited for floating and rolling. Found chiefly among some unicellular forms. Rare in animals.
Body divided into similar halves by more than 2 planes passing through longitudinal axis. Usually sessile, freely floating, or weakly swimming animals. No anterior or posterior ends. Can interact with environment in all directions.
Organism can be divided along a sagittal plane into to mirror portions. Much better fitted for directional movement. Associated with cephalization.
Nervous tissue, E.T.
gut and visceral organs, E.T
Simplest eukaryotic orgnisms
Whip like organelle of locomotion.
A hair like, vibratile organelle process found on many animal cells. Cilia may be used in moving particles along the cell surface, or in ciliated unicellular forms, for locomotion.
No division of labor. Cells live in colonies/groups, not one organism.
Cells take on different, specialized jobs.
Scale of analysis above species level occurs over geologic time (great periods of time). A change in the characteristics of a lineage through time. Change in allele frequencies through time.
Scale of analysis at the species or population level variation within a population. Changes in allele frequency from one generation to the next.