1. What kinds of organisms most likely gave rise to the first animals?
This cladogram represent the evolutionary relationships among major groups of animals.
What kinds of organisms most likely gave rise to the first animals?
sponges
Which evolved earlier, coelom or bilateral symmetry?
Bilateral symmetry
Which pair of animals is more closely related; annelids and arthropods or echinoderms and arthropods?
Annelids and arthropods

2. Animal kingdom has 9 phyla:
Phylum Porifera
sponges
Phylum Cnideria
jellyfish

3. Phylum Platyhelminthes
Flatworms, tapeworms
Phylum Nematoda
Roundworms

4. Phylum Echinodermata Phylum Arthropoda Insects Starfish, sand dollars
Spiders

5. Phylum Chordata
ALL vertebrates
Humans, dogs, snakes

6. Animals in the first 8 phyla are invertebrates, which means they DO NOT have a backbone.
The only phylum that contains vertebrates (animals with a backbone) is phylum Chordata.

7. Vertebrates are divided into 5 classes (or groups):
Fish- includes jawless fish, sharks and rays
Breathe through gills
Lay eggs in water
Have fins

8. Amphibians (term means double life)- includes frogs, toads and salamanders
Have smooth or bumpy skin
Lay eggs in water
Gills/lungs
Breathe through skin

9. Reptiles- snakes and turtles
Dry, scaly skin
Lay terrestrial eggs

10. Birds- owl, chicken and stork.
Have feathers
Lay terrestrial eggs

11. Mammals- human, dolphin, bear, bat and mouse
All have fur
Feed their young milk