1. CH. 26 WHAT IS AN ANIMAL?

2. WHAT ARE ANIMALS? Animals are multicellular Eukaryotes, heterotrophic organisms with cells that lack cell walls.

3. INVERTEBRATES VS. VERTEBRATES Invertebrate : no vertebrate; without a backbone Vertebrate : having a backbone/spinal column

5. ANIMAL BODY SYSTEMS

6. SUPPORT An animal’s skeleton supports the animal’s body and helps with movement. Hydrostatic (water - standing)- body cavity that is filled with water & helps with support Exoskeleton (outside – skeleton): hard, external supporting structure. Endoskeleton (inside – skeleton): internal skeleton made of bone & cartilage

7. WHAT SKELETON DO I HAVE?

8. BODY SYSTEMS Digestive & Excretory Systems: Digestive system – extracts (takes) energy and nutrients from the food Excretory system – removes waste products from the body Gastrovascular (Stomach – vascular) cavity: cavity for digestive & circulatory purpose in cnidarians

9. NERVOUS SYSTEMS Nervous system – carries information about the environment through the body & coordinates responses & behaviors. Nerve net – simplest arrangement of nerves Ganglia – cluster of nerve cells that coordinate responses ADVANCED: true brain with sensory structures

11. BODY CAVITIES Bilateral symmetry – 3 basic kinds of internal body plans Coelom – fluid-filled space found between the body wall and the gut Acoelomate (no body cavity) Pseudocoelom (false coelom) Coelomate (True coelom) – lined with mesoderm and wraps around the gut

13. CIRCULATORY SYSTEM Transports gases, nutrients, and other substances within the body. Open circulatory system: fluid leaves the blood vessels; washes the tissues Closed circulatory system: blood remains inside the blood vessels; small vessels in body tissues

15. REPRODUCTION Asexual reproduction: (no-sex) Sexual reproduction: male gametes (sperm) & female gametes (eggs)

16. BODY SYMMETRY How can an animal’s body be divided into similar pieces? Asymmetrical (a=no; symmetry=regularity of form) Radial symmetry – body parts arranged around a central axis Bilateral symmetry : mirror-image halves Cephalization – concentration of nerve tissue & sensory organs at the anterior end of an organism

18. SO WHAT IS AN ANIMAL?