In the upcoming slides you will see pictures of several arthropods In the upcoming slides you will see pictures of several arthropods. For each picture: Describe what you see. Be detailed! (Ex: How many legs, what color, what shape, ext)

Barnacle

Lobster

Beetle

Spider

Scorpion

Horseshoe Crab

Blue Crab

Krill

Ant

What do all of these organisms have in common? Write this in your “Characteristics of Arthropods” Before Box.

2. What characteristics do you think of when you hear “Crustacean”

3. Describe a unique characteristic of barnacles.

4. What do you know about “Decapods”

5. Why is krill important to the marine food chain?

Crustaceans

Arthropod Overview Phylum Arthropoda = arthropods (“jointed feet”) Characteristics Jointed appendages Tough exoskeleton made of chitin Varies from flexible to hard Acts as a protective cover Place of attachment for muscles

Crustacean Features Crustaceans: marine animals that have hard outer coverings Other characteristics include: Bilateral symmetry 2 main segments Cephalothorax (includes head and chest) covered by the carapace Abdomen (includes a tail if present)

Crustacean Features

Look at Those Legs! Crustaceans like crabs, lobsters, shrimps etc. have 5 pairs of legs (they are known as decapods) 1st pair = claws (used for food-getting) 2nd – 5th pairs = walking legs Some crustaceans have special swimmerets (located under the abdomen) that help them glide along the sea bottom

Growth Under the Exoskeleton Crustaceans shed their exoskeleton once or more during the year by molting. New exoskeleton is secreted inside the old one which splits open Animal pushes its body out through the gap between the thorax and abdomen New shell is very soft and the animal is vulnerable to predators

The Lobster Lobsters are able to release their arms from their sockets to get away from predators or other aggressive lobsters (they will regenerate the limb)

Fiddler Crab Named for its large claw which looks like the arm position of a person playing the fiddle; if a large claw is lost, a small one grows in its place and the other claw grows into a large claw

Mole Crab Adapted to live in the surf zone because of its streamlined body that helps it burrow into the sand

Hermit Crab Born without an exoskeleton on its abdomen, so it lives inside empty snail shells.

Structures and Activities of Crabs Structure of the Crab Segemented into cephalothorax and abdomen (which is very small) Both parts are covered by the carapace Female crabs have a U-shaped abdomen while male crabs have a V-shaped abdomen