Animal Body Plans (Test Two) Flashcards
How many Phylum appeared during the Cambrian explosion (the great oxygenation event)?
100 phyla appeared
How many major phyla exist today and have body plans that evolved during the Cambrian explosion?
32 major phyla
What are the four ways that animal body plans are different?
- Grade of organization
- Body Symmetry
- Number of embryonic germ layers
- Number and type of body cavities
Name the five major grades of organization, in increasing complexity.
- Protoplasmic
- Cellular
- Cell-tissue
- Tissue-organ
- Organ-system
Describe the Protoplasmic grade of organization.
They perform all basic functions of life within one cell, having organelles with specific functions.
The diversity is in the structures that compose them
Describe the Cellular grade of organization. (Think sponges)
Cells are combined into a large group of cells, and demonstrate a division of labor, and perform specialized tasks.
Can’t survive on own
Describe the Cell-Tissue grade of organization. (think jellyfish)
Some cells are grouped to perform a common function as a unit (tissue), but many cells are scattered around the body.
Describe the Tissue-Organ grade of organization.
groups of tissues are assembled into larger functional units called organs, which have specialized functions.
Example is flatworms
Describe the Organ-System of Organization
When several organs work together to perform a common function for the survival of the animal.
Example is phylum arthropoda or phylum chordata
What is symmetry?
Symmetry is a balance of proportions and the correspondence of size and shape on parts on both sides of a medial plane.
Explain Spherical Symmetry.
Any plane passing through the central point divides the body into mirrored halves.
Example is unicellular (radiolarians )
Explain Radial Symmetry.
When the body is divided into similar halves by more than one plane passing through a longitudinal axis (like slicing a pie)
Example enchinodermata
Explain Biradial Symmetry.
When most of the organism is radially symmetrical, but has a part that is single or paired rather than radial
Example is ctenophores (sea gooseberry)
Explain Bilateral Symmetry.
When an organism is divided into right and left along a sagittal plane into two mirror images.
What is associated with Bilateral Symmetry?
Cephalization.
What is cephalization?
Cephalization is the concentration of nervous tissues and sensory organs at the anterior of an organism.
What is bilateral symmetry best suited for?
Bilateral symmetry is best fitted for forward movement in the environment, and it is also advantageous to an animal moving forward head first.
What is Anterior and Posterior?
Anterior is head end.
Posterior is tail end.
What is dorsal and ventral?
Dorsal is back (upper) side
Ventral is fron (belly) side
What is medial and lateral?
Medial is the midline of the body.
Lateral is the right and left sides
What is distal and proximal?
Distal is parts farther form the middle of the body
Proximal is parts nearer to the body
What is the frontal (coronal) plane?
The frontal plane divides the body into dorsal and ventral halves
What is the sagittal plane?
The sagittal plane divides the body into right and left.
What is the transverse (cross sectional) plane?
Transverse plane divides the body into anterior and posterior halves.
