General+Body+Structure-Lauren+Giavedoni

1. Explore the type of symmetry that each organism has. Pig-Bilateral. -Bilateral symmetry is when you cut something down the middle and the two halves are exactly alike. Crayfish-Bilateral -Bilateral symmetry is when you cut something down the middle and the two halves are exactly alike. Starfish-Radial -Radial symmetry is when an organism only has a top or bottom side, no left or right. It's like cutting a pie, if you would cut parts of the organism, they would be relatively alike.
 * IV. General Body structure: **

2. Label a picture of the organism with these terms: anterior, posterior, dorsal, ventral, lateral, head, thorax, and abdomen.

Pig.



Crayfish.



Starfish.

3. What is the advantage of various structures found on the body such as appendages, mouth parts, sensory antennae, skin receptors, etc. Discuss all the different types of receptors.

There are many advantages of appendages, mouth parts, sensory antennae, and skin receptors. Appendages are body parts that extend from a body segment. Examples of these are legs, claws, tails, and tube feet. In pigs and crayfish, the legs are what the animals walk on. A crayfish has a tail which helps it to swim, and it also has claws to grab food. Lastly, a starfish has tube feet which makes it suction cup onto rocks and it can filter water to get food. Mouth parts are important because that is what each of the animals eat from. The food starts in this part of the body and goes into the digestive system. A crayfish is the only three of the animals that has sensory antennae. The antennae of a crayfish helps it feel around for food and to help it move around and "see" where it's going. The pig has skin receptors. The sensory receptors of the skin are concerned with at least five different senses: pain, heat, cold, touch, and pressure. The skin receptors let the animal feel different things that its around such as water or mud.

My question is why do pigs have tails? Do they serve a purpose? On wikipedia, I found the answer that pig tails do not serve a purpose. When raising pigs, pig farmers usually dock or remove a pigs tails. They do this to prevent tail biting, which is when the animals bite each others tails. Without tails, pigs aren't much difference. The tails aren't used for anything, so removing them isn't a problem.