Morphology General Zoology, 24 January 2011 Donald Winslow Readings from Hickman et al. 2011: Ch. 9 pp 185-189, 191-193, 195-196

Morphology Biological hierarchy Grades of organization & body plans Describing locations on animal bodies Body cavities & germ layers Developmental patterns Histology Body size

Biological hierarchy Cell Tissue Organ Organ system Organism Population Community Nine-banded armadillo

Grades of organization Protoplasmic (e.g. protozoa)‏ Cellular (e.g. colonial protists, sponges)‏ Tissue or “cell-tissue” (e.g. jellyfish)‏ Organ or “tissue-organ” (e.g. flatworm)‏ Organ system (e.g. molluscs, arthropods)‏ Luna moth

Body plans Unicellular protists vs multicellular animals Protozoa vs Metazoa Cell-level vs tissue-level organization Porifera vs Eumetazoa Radial symmetry vs bilateral symmetry Sac vs “tube-within-a-tube” digestive tracts Acoelomate, pseudocoelomate, coelomate

Patterns of symmetry Bilateral symmetry Radial symmetry Photo by Richard Snow

Describing location on animal Anterior/posterior Dorsal/ventral Medial/lateral Distal/proximal Frontal, sagittal, and transverse planes

Body cavities Blastocoel Gastrocoel (archenteron)‏ Pseudocoel Coelom

Germ layers Endoderm Mesoderm Ectoderm

Developmental patterns Cleavage—radial or spiral Gastrulation (germ layer formation)‏ Diploblastic or triploblastic Protostome or deuterostome Metamerism (segmentation)‏

Histology Blood plasma and interstitial fluids Tissues Endoderm epithelium of digestive tract Ectoderm skin & nervous tissue Mesodermconnective tissue, muscles, viscera Connective tissue: collagen, blood, lymph, cartilage, bone, fat

Advantages & disadvantages of large body size Predators can subdue larger prey, But larger prey can’t hide as easily. Larger animals have efficient metabolism, But use more energy. Larger animals have longer generations.

Humpback whale