Ch. 1 Classifying organisms: How do we classify Invertebrates? Lesson 3

Animals without Backbones Most animals on Earth are INVERTEBRATES Some are microscopic Others quite large (giant squid) Mollusks, worms, cnidarians and anthropods Cnidarians (stinging cells to catch pray)

Mollusks Soft body without bones Snails, slugs, clams, squids Some have hard outer shells May have gills May absorb oxygen through their skin

worms Many different types Flatworms = thin, live in wet or damp places Roundworms = live in water or on land Segmented Worms include earthworms Some are microscopic & some are huge 7 meters long (largest)

CHECKPOINT List 3 different invertebrates. How are they alike? How are worms and clams alike? Different? What is the largest invertebrate? How do mollusks get oxygen?

Arthropods – “Jointed Feet” Insects, lobsters, & spiders This is the largest phylum of animals Bodies are divided into separate parts Invertebrates Get Oxygen different ways: Gills Grasshoppers/ tubes carry oxygen Spiders use organs/ book lungs

“weird science . . . What’s Older than a Dinosaur…?” The Horseshoe Crab has been around for about 450 Billion years and its blood is the color ______? Scientists harvest the blood of the horseshoe crab because it contains a molecule crucial for medical research. (Immune Cells) They do not use hemoglobin in their blood to transport oxygen instead they use hemocyanin, which contains copper, causing their blood to be blue.

Misconceptions: Insects do not shed their skin Insects can’t “Breathe”- no lungs Spiders are not Insects A spider’s body has 2 segments Spiders are in the class Arachnida, even though it’s a invertebrate

Butterflies, moths, & houseflies: Life cycles with big changes

Dichotomous Key: use the key on pg. 21 to identify these animals