GROUP NUMBER: 3 DATE: January 23, 2011NAME: Laurice Aiken B. Tumanda

ANIMAL FORMS AND STRUCTURESANATOMICAL POSITION AND BODY SYMMETRY

I. INTRODUCTION: Animals are classified in a large group of multi-cellular, eukaryotic organisms of Kingdom Animalia. Most animals are motile so they can move spontaneously and independently. They are also heterotrophs so they must ingest other organisms or their products for them to survive. Animas have their specific body plans also which becomes fixed as they develop. Body plan is describe as the basic shape of members of an animal phylum. It is the general structure each individual organism assumes as itdevelops. The simple process of nutrient capture, digestion, and waste disposal is fundamental to the body plan of advanced, free-moving Animal body plans include the following:A. Formation of Coelom - Protostomes vs Deuterostomes - In echinoderms and chordates, for example, the anus forms first, and then the mouth. On the other hand, animals belonging to other important phyla such as arthropods, annelids and mollusks, the mouth forms first, followed by the anus. For this reason arthropods, annelids and mollusks are sometimes called protostomes (Greek: proto = the first; stoma = mouth) and echinoderms and chordates are called deuterostomes (Greek: deutero = the second; stoma = mouth). B. Body Cavities - One of the primary ways zoologists’ group animals has to do with the presence or absence of a coelom, and how the coelom is formed. A coelom (Greek:  coel = hollow; pronounced “see-lome”) is a fluid-filled cavity between the alimentary canal and the body wall.  However, the type of coelom (or even its existence) differs among groups of animals – both in its structure (such as what types of tissues surround it) and its mode of development.  There are three structural types of body plans related to the coelom, as shown below.

TISSUE LAYERS AND CAVITIES BODY PLAN TYPE

a. Acoelomate - no coelomic cavity exists. b. Pseudocoelomate - a coelom exists, but it is lined by mesoderm only on the body wall, not around the gut.c. Coelomate (or Eucoelmate, or “True” Coelom) - the coelom is lined both on the inside of the body wall and around the gut by mesoderm.  Animals with a true coelom also have mesenteries, which suspend the body organs within the coelom.

Acoelomate

Pseudocoelomate

Coelomate

Ectoderm

Gut

Mesoderm

Pseudocoel

Coelom

Endoderm

C. Symmetry - Animals show different patterns of body symmetry. Some groups, such as the phylum Porifera, show no particular pattern of symmetry (asymmetry). That is, no line of bisection exists that could divide the organism into similar-looking halves. Other groups, including the Cnidaria and Echinodermata show radial symmetry wherein more than one hypothetical bisection can be visualized (lines A, B, and C can each bisect the organism). A third pattern, seen in most phyla of animals, is bilateral symmetry, where only one hypothetical bisection can be visualized (only line A can bisect the organism into two halves). 

II. OBJECTIVES:III. MATERIALS

pencil/pen crayons books/websites for references

IV. PROCEDURES:1. Using such references, the researcher looked for those animals that exhibit asymmetry,

radial symmetry and bilateral symmetry. Five animals in each of that different body symmetry were then illustrated.

2. On the same illustrations, the researcher located the anatomical positions of each animal.3. The researcher searched for the anatomical position of frog and human then compared

them.

V. RESULTS and DISCUSSIONS:FIGURE 1: Animals that exhibit ASYMMETRY

FIGURE 1.A FIGURE 1.B

BILATERAL SYMMETRY

RADIAL SYMMETRY

ASYMMETRY

FIGURE 1.C FIGURE 1.D

FIGUR 1.EFIGURE 2: Animals that exhibit RADIAL SYMMETRY

FIGURE 2. A FIGURE 2.B

VI: CONCLUSION:

VII. REFERENCES: http://en.wikipedia.org/wiki/Animal http://dictionary.reference.com/browse/body+plan http://en.wikipedia.org/wiki/Body_plan http://userwww.sfsu.edu/~biol240/labs/lab_16animalbodyplan/pages/bodyplan.html http://en.wikipedia.org/wiki/Symmetry_(biology)