Mr. Bouyer
Day 1 | Day 2 - 4 | Lab | Reading Assignment

Describe the characteristics of the Phylum Arthropoda. Compare the molting of a grasshopper with the molting of a crayfish. Describe the characteristics of the Subphylum Crustacea. Know at least two Texas representatives of the Subphylum Crustacea. Describe the characteristics of the Subphylum Chelicerata. Know at least four Texas representatives of the Subphylum Chelicerata. Describe the characteristics of the Subphylum Uniramia. Know two Texa representatives of the Subphylum Uniramia that do not have six legs. Compare complete and incomplete insect metamorphosis. Use a dichotomous key to identify Texas insect Orders.

Animal Identification Assignment.

The exoskeleton of arthropods is secreted by the epidermis, however, the exoskeleton must be larger than the animal to give it room to grow. How does an arthropod produce an exoskeleton that is larger than its body?

Phylum characteristics: Jointed appendages Segmented body Exoskeleton Ventral nervous system Open circulatory system Sensory receptors

Which phylum characteristics are visible in this picture?

Three quarters of all animal species belong to the Phylum Arthropoda. Their jointed appendages and segmented exoskeleton are the most distinctive arthropod traits. Unlike the muscles in the animals we have studied so far, arthropod muscles do not form continuous sheets. Arthropod muscles occur in bundles that are attached on either side of the joints in the exoskeleton. This gives arthropods a vastly improved system of locomotion.

The exoskeleton is composed of a tough calcium containing compound called chitin (KITE - 'n). The exoskeleton is composed of three layers, secreted by the epidermis that lies just beneath:

• The tough, waxy outer layer repels water and keeps terrestrial arthropods from drying out.
• The thick, hard middle layer is rich in calcium and provides protection for the inner body parts.
• The thin, inner layer is flexible at the joints allowing the animal to move freely.

Once formed, the exoskeleton cannot enlarge as the soft body tissues grow. As the body grows, it puts more and more pressure against the inside of the exoskeleton. Eventually, this pressure triggers the process of molting, the splitting of the old exoskeleton and formation of another.

The steps of the molting process are:

• The epidermis secretes an enzyme that digests the inner layer of the exoskeleton.
• At the same time, the epidermis uses the digested material to begin building a new exoskeleton.
• When the inner layer is weak enough, the old exoskeleton splits along specific lines allowing the the animal to "shed" the old exoskeleton.
• At first, the new exoskeleton is soft. The animal will draw in air or water, depending on its habitat, to swell the new exoskeleton larger than its body.
• Once the new exoskeleton hardens, the animal releases the excess air or water allowing the body to shrink back to normal size. This leaves some space for growth between the exoskeleton and the soft body parts.

  Computer Assignment 074:
  This assignment must be completed this week to receive credit.
  PowerPoint Evaluation Rubric

  The assignment for this week is to make a four page report about the Phylum Arthropoda using Microsoft Word. You will begin the report today and add to it each day this week. The completed report is to demonstrate your overall command of special effects in Word and your desire to build a professional report.

  Page 1

  1. Paste the picture at the top of this page onto the top right of a Word page.
  2. Use WordArt to title the page "Arthropod Characteristics". Align the title and characteristics to the left of the picture.
  3. Use WordArt to make a heading "exoskeleton" below the picture.
  4. Briefly describe how an arthropod makes its new exoskeleton larger than its body.
  5. Save this file to continue tomorrow.

Day 2 - 4

To what part of the body are insect wings attached?

Arthropod predators:

The arthropod predators of insects and mites include beetles, true bugs, lacewings, flies, midges, spiders, wasps, and predatory mites. Many of these are being successfully used as a "biological" control of pests.

Arthropod classification:

All living members of the Phylum Arthropoda are in these three subphyla:

• Day 2Subphylum Crustacea (kruss-TAY-shuh)
  Members are distinguished for having chewing mouthparts called mandibles and branched antennae.

• Day 3Subphylum Chelicerata (kuh-liss-uh-RAHT-uh)
  Members are distinguished for having pincerlike mouthparts called chelicerae and no antennae.

• Day 4Subphylum Uniramia (yoo-nuh-RAY-mee-uh)
  Members are distinguished for having mandibles and unbranched antennae.

Research Links:

• Insect Flight - Nurse Minerva

Zoology Class

When an arthropod is ready to secrete a new exoskeleton it will expand its body by taking in air or water, depending on its environment. The animal will retain this expanded body until the new exoskeleton hardens. When the water or air is released, the body shrinks, leaving space for the animal to grow normally inside the new exoskeleton.

When insects have wings, they are attached to the cephalothorax.