Animal Kingdom Overview and Classification

Study Notes

The animal kingdom is one of the largest kingdoms on Earth
It contains millions of different species, with thousands more being discovered each year
Animals are categorized into nine major phyla

Vertebrates have a backbone (internal skeleton)
Invertebrates do not have a backbone
Both groups have a nervous system (for vertebrates, this includes a brain and spinal cord)

Vertebrates include five main classes: mammals, birds, amphibians, fish, and reptiles
Each class has unique characteristics

Arthropods are a major group of invertebrates
Arthropods have three characteristics; exoskeleton, segmented bodies, and paired jointed appendages
Some examples of arthropods include arachnids, crustaceans, and insects

Mammals are warm-blooded, nourish young with milk and have hair/fur
Birds have feathers, are warm blooded and lay eggs , have beaks instead of teeth
Amphibians are cold-blooded, live in water and on land, and have moist skin
Fish are cold-blooded, live in water, breathe through gills, and have scales
Reptiles are cold-blooded animals that lay eggs, have scales or bony plates, and breathe air
Arachnids (e.g., spiders) lack jaws, usually inject digestive fluids before sucking prey.
Crustaceans (e.g., crabs) have two pairs of antennae. They have mouths made up of one pair of mandibles and two pairs of maxillae
Insects (e.g., bees) have three main body parts (head, thorax, and abdomen), three pairs of legs and usually, two pairs of wings. An exoskeleton is a hard, shell-like covering.

The provided text suggests online resources, activities, or further study on specific animal classes. Further study is suggested based on the given text.