Animals and their Characteristics

Invertebrates

Sponges Animals that have no true organization. Asymmetrical: body plain cannot be divided into mirror images.

Cnidarian Soft-bodied, aquatic creatures. Radial symmetry: body plan in which all body parts of an organsm are arranged around a central point.

Jellyfish

Sea Anemones

Corals

Worms There are thre groups: flatworms, roundworms, and segmented worms. Bilateral symmetry: is a body plain in which an organism can be divided along only one plane of their body to produce two mirror images.

Mollusks Animals with a muscular foot or tentacles, a fold tissue called mantle, and internal organs. Almost all mollusks have a shell. Examples: snails, clams, and squids.

Snail

Echinoderms They have endoskeletons. Use a water pressure system that helps them feed, breathe, and move. Examples: sea stars, sea urchins, and sea cucumbers.

Arthropods The most numerous animal group on Earth. They are small and light with a hard exoskeleton. Examples: spiders, crabs, and insects.

Vertebrates

Fish There are three classes of fish: jawless fish, cartilaginous fish, and bony fish.

Amphibians Animals that spend part of their lives in the water and part on land. Examples: frogs, toads, and salamanders.

Reptiles Animal with one or two lungs, thick, scaly, waterproof skin. Examples: lizards, snakes, turtles, alligators, and crocodiles.

Birds Animals that rather than four legs have two legs and two wings. Birds also have hollow bones to reduce their weight.

Mammals Characteristics of mammals are that they have hair, milk to their young and have large brains. They are divided into 3 subclasses

1. Monotreme A mammal that lays eggs.

2. Marsupial A pouched mammal. They give birth and then carry their young in a pouch on the front of their bodies.

2. Placental mammals The young develops within the mother.