1. Animals are grouped based on their body structure, food, and habitat.
2. The two main categories are vertebrates and invertebrates.
3. Vertebrates are animals that have a backbone.
4. Invertebrates are animals that do not have a backbone.
5. Mammals are warm-blooded vertebrates that give birth and produce milk.
6. Birds are vertebrates with feathers and beaks that lay eggs.
7. Reptiles are cold-blooded vertebrates with dry, scaly skin.
8. Amphibians live both in water and on land during their life.
9. Fish are aquatic vertebrates with gills and fins.
10. Insects are small invertebrates with six legs and three body parts.
What characteristics differentiate amphibians from reptiles, despite both being cold-blooded?
If an animal lives in water and breathes with gills, is it always a fish? Why or why not?
How do scientists decide whether an animal belongs in a new species or an existing one?
Can two animals look alike but belong to completely different classifications? Give examples.
Which group does the platypus belong to, and why does it challenge traditional classification?
Are all invertebrates more closely related to each other than to vertebrates? Why or why not?