Invertebrates

97% of all animals are invertebrates (19 out of 20).
See tree of life at https://opening.download/spring-2021.html (vertebrates are part of chordates)

Look at the real invertebrate animals at four stations.
Draw them.

How do they eat, do you think? How might they defend themselves, do you think?

Summarize and look at on tree of life:
Worm eats with mouth. Defends by moving away (makes slime to help move through the soil).
Daphnia eats with mouth. Defends by moving away.
Barnacles eat with their cirri (modified legs) by sieving. Defends with shell.
Freshwater shrimp eats with mouth. Defends by moving away and with exoskeleton.
Wood bugs eat with mouth. Defends by moving away, with exoskeleton, and by camouflage.

How they are related:
Worms least related to the rest, then
Daphnia (pond organism) least related to the rest, then
Barnacles least related to the last two
Freshwater shrimp (pond organism) most related to wood bugs

Information about animal evolution:
Of animal phyla making it onto land, Annelids and Molluscs need a moist environment, whereas Arthropods and Vertebrates can live on dry land.

Info about Vertebrates:
Bones evolved with increasing size and more active foraging for food.
Cephalized (with neural and sensory (navigation) equipment concentrated in the head as the brain, protected by the skull). 
Vertebral column and attached muscles allow for more active swimming and foraging.
Ribs attach more muscles and protect organs.
As an endoskeleton, it can grow with the animal (unlike exoskeletons).
Increased metabolism supports more movement.