The general body plans of animals. biology

The General Body Plans of Animals

Prepared by:Group 1 Morning

Joseph Martin PaetGladys Kim Remolacio

Jesebel GarlanRuby Cocal

Jeremy Nacido

INTRODUCTION Most animals are bilaterally symmetric, including humans.It could be divided into matching halves by drawing a line down the center.It permits streamlining, favors the formation of a central nerve center, contributes to cephalization, and promotes actively moving organisms.

 Radially symmetric animals are symmetrical about an axis extending from the center of the oral surface.

Radial Symmetry

Coral

Jelly Fish

Asymmetrical Do not show definite symmetry.

REGIONS Segmentation the division of some animal body plans into a series of repetitive sections. “Advanced” animals have body segments, and specialization of tissue.

Metamerism segments are similar with each other.Tagmatization segments are different and may become fused to fused to a functional groups/tagmata.

Terms to be Familiar With

Anterior head-end

Posterior tail-end

Cephalic toward the head

Caudal toward the tail

Dorsal back side

Ventral belly side

Lateral on or toward the side

Medial on or toward the middle

Proximal toward the central part

Distal toward the extremities

Peripheral near the surface of the body

The Sea Star The sea star has a radial symmetry.

PARTS OF A STAR FISH

Figure 7.1

The RoundwormAscaris lumbricoides, a common intestinal roundworm having a bilateral symmetry. It lacks true segmentation and appendages. It is covered with a tough, elastic cuticle, bearing minute striations. Four whitish longitudinal lines extended along the body, one dorsal, one ventral, and two lateral. The mouth opens at the anterior end between three rounded lips. The anus is a transverse slit close to the posterior end of the ventral surface.

Figure 7.2

The Earthworm The Pheretima has a bilaterally symmetrical body, long and cylindrical, bluntly tapered at each end, and somewhat depressed posteriorly. The body is organized in a linear series of similar segments (somites/metameres) which is called mesmerism. The mouth is in the first somite and the vertically oval anus, in the last somite. The clitelium is a conspicuous glandular swelling over the somites 32 to 37. Setae – minute, rod-like chitinous appendages.

Clitelium

Mouth

Anus

Somites

Figure 7.3

It is divided into three segments.

The segments are not similar and is referred to as tagmata.

The Cockroach

1. The Head

Figure 7.4

Ocelli

Gena

Compound eyes (ommatidia) Antennae

2. The ThoraxCervix

The cervix (neck) connects the head to the thorax.

Figure 7.5

2. The Thorax

Pulvillus

Pretarsus

2. The Thorax

The prothoracic plate is a broad plate located anteriorly.

Prothoracic plate

Figure 7.6

Forewing spread in the mesothorasic area while the hind wing is on the metathorasic area. The hindwing is the one used in flight.

2. The Thorax

Forewing/Elytrom

Hindwing

Figure 7.6

Cercus

Figure 7.7

2. The Thorax

3. The Abdomen

Spiracles are apertures for gas exchange.

Male

Female

The Shrimp

The head and the thorax are fused at the cephalothorax.

Figure 7.8

The Toad

1. The Head

Nictitating Membrane

Parotid Glands

2. The Trunk

Belly

Hump

Anus

Foreleg

Hindleg

Forearm

Finger

Thigh

Shank

Ankle

Foot

Webs

Male

Female

Figure 7.9

Answers to Self Assessment Question

SpeciesSegment

s present

Number of Legs &

segments attached

Appendages present

Sensory Organs present

and segments

where attached

Cockroach 6 legs; 11 seg.

Head, Thorax, Abdomen

Antennae, Cerci, eyes

Shrimp 6 w. legs; 11 seg

Cephalothorax, Abdomen, tail

Antennae, eyes

Crab 6 legs; 8 seg. Abdomen, head

Antennules, eyes

Spider 8 legs: 9 seg. Cephalothorax, abdomen

Ear, hair, eyes

1. Compare and contrast the following invertebrates based on the following:

Species Locomotory Organs Habitat Body

CoveringBody

Regions

Fish Tail and fins Water Scales Head, trunk, tail

Toad Legs Both land and water Scales Head, trunk

Cow Legs Land Fur Head, trunk

Birds Wings and legs Land Feathers Head, trunk,

tail

Snake Tail, body Land and water Scales Head, tail

2. Compare and contrast the tod with fish, other amphibians, reptiles, birds, and mammals based on the following:

What is the adaptive significance of segmentation in animals?

Segmentation is the division of an animal into similar parts. It's main significance is that it provides a simple way of making a small animal into a larger one - basically by duplicating a segment two or more times an animal can be made bigger without complex alterations. This has particular significance in evolution where it is generally believed that larger animals evolved through a simple genetic mutation which generated multi-segmented forms from non-segmented forms.Segmentation is visible to one extent or another in virtually all larger fauna - from insects and earthworms to vertebrates (the spinal column is an example of segmentation - the repeated use of vertebral disks to create a larger creature than would easily be possible by simple enlarging one vertebra)

THE END