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

2. 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)

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

5. 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)

6. 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?

7. 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

8. “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.

10. 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

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

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