Something is symmetrical when it is the same on both sides. A shape has symmetry if a central dividing line (a mirror line) can be drawn on it, to show that both sides of the shape are exactly the same.

1 : having, involving, or exhibiting symmetry. 2 : having corresponding points whose connecting lines are bisected by a given point or perpendicularly bisected by a given line or plane symmetrical curves.

If a figure can be folded or divided into half so that the two halves match exactly then such a figure is called a symmetric figure. The figures below are symmetric. The dotted line in each of the symmetric figures above that divides the figure into two equal halves is called the line of symmetry.

The most advanced body plan is bilaterally symmetrical. Bilaterally symmetrical animals (such as humans) have a symmetry that produces mirror halves. “Mirrored halves” means that if we cut ourselves in half and place one half in a mirror, it will look exactly like the other half.

The human body plan is bilateral with symmetrical sense organs, a fast responding brain, half the body weight in muscles, a powerful heart, and miles of arteries and veins and a brain that coordinates it all. All large active animals have this same body plan.

Grouping animals with these body plans resulted in four branches: vertebrates, molluscs, articulata (including insects and annelids) and zoophytes or radiata.

The morphology of the simplest sponges takes the shape of a cylinder with a large central cavity, the spongocoel, occupying the inside of the cylinder. Water can enter into the spongocoel from numerous pores in the body wall. Water entering the spongocoel is extruded via a large common opening called the osculum.

Porocytes are cylindrical cells that make up the pores or ostia. Water enters the animal through the pores formed by these cells. The flow of water into the sponge body is not only crucial for feeding and digestion, but also for circulation within the sponge.

Leuconoid sponges are the best adapted to increase sponge size. This body plan provides more circulation to deliver more oxygen and nutrients per area in large sponges.

There are three planes commonly used; sagittal, coronal and transverse.

Terms in this set (7)

• 6 basic features humans share with other vertebrates. – tube within a tube body plan.
• tube within a tube body plan. inner tube: mouth to anus, respiratory and digestive organs.
• bilateral symmetry.
• dorsal hollow nerve cord.
• notochord and vertebrae.
• segmentation.
• pharyngeal pouches.

Animals can be classified by three types of body plan symmetry: radial symmetry, bilateral symmetry, and asymmetry.

A body plan is a group of structural and developmental characteristics that can be used to identify a group of animals, such as a phylum. All members of a particular group share the same body plan at some point during their development—in the embryonic, larval, or adult stage.

Abstract. A body plan is a suite of characters shared by a group of phylogenetically related animals at some point during their development. The concept of bauplane, or body plans, has played and continues to play a central role in the study of evolutionary developmental biology (evo-devo).

The three basic body plans of bilaterally symmetrical animals are acoelomates, wherein nobody cavity other than the digestive tract exists; pseudocoelomates, wherein there is a cavity between the mesoderm and the endoderm; and the coelomates, where there is a cavity completely bounded by mesoderm.

A group of genes known as homeobox (Hox) genes control embryonic development of the body plan in a wide range of animals, from humans and fruit flies to cats to beetles. Together, the combined Hox-TALE binds to the DNA of downstream genes and switches them on, setting the development of an antenna or a leg into motion.

Early patterning of the body during animal development is a fundamental process to subsequent events including cell differentiation, tissue and organ formation, and correct function of the adult body. All of these outcomes can have dire effects on the body (Fig. 1).