MorphologyGeneral 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

• Mesodermconnective tissue, muscles, viscera– Connective tissue:

» collagen, blood, lymph, cartilage, bone, fat

Advantages & disadvantagesof 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