BIOL 2030 Chapter Notes - Chapter 3: Sagittal Plane, Blastocoel, Gastrointestinal Tract
Document Summary
There are 5 major levels of organization in organismal complexity: protoplasmic level: unicellular organisms, cellular level: colonial (aggregation of unspecialized cells, all able to reproduce) or multicellular (aggregation of cells that are functionally differentiated, reproduction is limited). May secerete an extracellular matrix (ecm): cell-tissue level: similar cells aggregate into definite patterns or layer, thus becoming a tissue. Eg. jellyfish: tissue-organ level: organs usually contain more than one kind of tissue and have a more specialized function than tissue. Flatworms: organ-system level: organs work together to perform a function. Systems are associated with basic body functions: respiration, digestion. Asymmetrical bodies are not balanced, there is no plane through which they can be divided into identical halves. Spherical symmetry means that any plane passing through the center divides the body into equivalent halves. (more in protozoan groups, suited for floating or rolling) Radial symmetry: can be divided into similar halves by more than two planes passing through the longitudinal axis.
