Honors BiologyModule 12 Arthropods

February 20, 2014

Class Challenge

Caterpillars 4-H Club

My Mistake on the Homework Assignment

Begin Reading Module 12Finish OYO for Module 11Finish Study Guide for Module 11Take Module 11 Test

Missing Assignments

Please see me at the end of class.

Quiz

• Earthworm Diagram

Phylum Arthropoda

Not having a backbone isn't as bad as it seems for some creatures. 

In fact, more than 95% of the world's animal population is spineless!  They crawl on the ground, fly in the air and skim across the water.

They also have an amazing effect on the environment

1. Help plants reproduce by carrying pollen from one plant to another.

2. They produce useful items such as silk, wax, honey, and drugs.

Some anthropods are very necessary for the earth’s ecosystem, they can also be very dangerous.

1. Transmit deadly diseases.2. They can destroy millions of acres of crops.

Phylum Arthropoda

1. Crayfish2. Lobsters3. Spiders4. Scorpions5. Insects

Arthropods have 5 Common Characteristics

1. All Arthropods have an Exoskelton

Which is a body covering that typically is made of chitin, that provides support and protection.

As the animal grows, it must molt or shed an old outer covering so that it can be replaced with a new one.

2. Body Segmentation

The body is divided into three major divisions:1. Head2. Thorax- region between the head and

abdomen.3. Abdomen- region posterior to the thorax

Some arthropods have the thorax and head united in a single segment called a cephalothorax

This segmentation is necessary in order to allow the exoskeleton to shift with the movements of the body.

Think of it like “joints” in the “armor”

3. Jointed Appendages

Arthropoda means “joint-footed”. Their appendages are jointed. Their muscles form under the exoskelton, moving the joints from underneath.

4. A Ventral Nervous System

Two ganglia form a brain (remember the earthworm), but it is more complex. The ventral nerve cord runs from the ganglia along the underside of the body to provide maximum protection from the exoskeleton and the bulk to the body.

Arthropods do everything they can to protect the underside of their body protecting the ventral nerve cord.

The Nervous System Is fed information through sensory organs.Antennae in the head region provide touch,

taste, and smell sensations to the nervous system.

All Arthropods have Eyes

Compound eye: an eye made of many lenses, each with a very limited scope

Simple eye: an eye with only one lens

See figure 12.1

5. An Open Circulatory System

Arthropods have quite an unusual circulatory system. In order to bring vital substances to every cell in the body, a heart in the dorsal (upper) region pumps blood into short vessels that empty out into different cavities of the body.

This allows blood to flow right over all of the cells in that cavity.

All Arthropods have

Bilateral Symmetry

Dissection of a Crayfish

Crayfish Anatomy Part 1http://youtu.be/2cBGuEDxvNo

Crayfish Anatomy Part 2http://youtu.be/wSGEt1mY2OM

Crab Dissection

Homework

Read Module 12 pages 365 – 376;OYO questions: 12.1 – 12.5;Study Guide questions: define a-h, 2-11;Complete Lab book: Crab anatomy;Quiz: External and Internal Anatomy of a

crayfish;Class Challenge: