animal body plans Flashcards
animal body plans differ in
and of type of body cavities
-grade of organization
-body symmetry
-number of embryonic germ layers
- number and type of body cavities
what are the five major grades of organization
-protoplasmic
-cellular
-cell-tissue
-tissue-organ
-organ-system
protoplasmic
unicellular-simplest eukaryotes organisms, perform all basic functions of life within the confines of a single cell; independent
-contains organelles with specialized function
-example: protozoa
cellular grade
have greater structural complexity by combining cells into larger aggregates
-cells demonstrate a division of labor
-cells cannot live alone
-example: volvox and sponges
cell-tissue grade
some cells group together into patterns or layers to perform a common function as a tissue
-some other cells can remain scattered and be independent
tissue-organ
aggregated tissues assembled into larger functional units-organs
-example: flatworms
organs can be composed of more than ___ kind of tissue and specialized function; tissue organ
one
organ system
several organs work together to perform function for the survival of the animal
-example: arthropods and chordates
spherical symmetry:
any plane passing through the central axis divides the body into mirrored halves
-best suited for rolling and floating; unicellular
radial symmetry
body divided into similar halves by more than two planes passing through longitudinal axis
mostly radially symmetrical but have part that is single or paired rather than radial
biradial symmetry
bilateral symmetry
organisms divided along sagittal plane into two mirror portions forming right and left halves
bilateral symmetry is associated with ____ and is better for ___ movement
-cephalization
-directional
body cavity
internal space represented by gut cavity and fluid-filled body coelom that cushions and protects internal organs.
acoelomate
no body cavity
