Chapter 25 : Sponges & Cnidarians

1. Chapter 25 : Sponges & Cnidarians I. Introduction to the Animal Kingdom A. What is an animal? Kingdom Animalia – kingdom of multicellular, eukaryotic, heterotrophs whose cells don’t have cell walls. Characteristics of Animals 1. Are heterotrophs 2. Are multicellular– include following in order from simplest to complex : cells tissues organs organ systems organisms

2. Tissues Found in Animals -Bodies of animals contain tissues : a. Epithelial – covers body surfaces. b. Muscular – contract & move animal’s body parts. c. Connective – support animal’s body & connect its parts. d. Nervous – carry information through body of animal. 3. Are eukaryotic 4. Do not have cell walls

3. Symmetry 5. Have symmetry a. Radial symmetry – balanced arrangement of body parts around a central point/center line, ex : starfish. Can divide on many planes. b. Bilateral symmetry – body is divided lengthwise into 2 equal/similar parts of right & left, ex : humans. -Can only be divided on a single plane. c. Asymmetrical – having no definite shape, ex : Sponge.

4. Body Directions 6. Body can be divided into directions Dorsal – upper or back surface Ventral – lower or belly surface Anterior – towards the head Posterior – towards the tail

5. Reproduction & Cephalization 7. Can reproduce sexually or asexually 8. Have cephalization – concentration of sense organs & nerve cells at the front end of the body – a head. -Some animals are segmented (made up of repeating similar parts) with appendages (outgrowths of the body like arms) coming from each segment. 9. Have a body cavity.

6. Major Categories of Animals 2 Major categories of animals : 1. Invertebrates – animals that have no backbone or vertebral column, ex : worms, jellyfish, insects. 2. Vertebrates – animals that have a backbone, ex : humans, dogs, cats.

7. B. What Animals Do to Survive -In order to survive, animals must carry out the following functions : 1. Feeding – most animals ingest food. Are consumers (eat other organisms). Types of feeding : a. Herbivores – animals that eat only plants, ex : cows, snails, pandas, etc. b. Carnivores – animals that eat only other animals, ex : wolf, tiger, etc. c. Omnivores – animals that eat both plants & animals, ex : human, bear. d. Detritivores – feed on dead or decaying plant/animal material.

8. Other Important Functions 2. Respiration – all animals respire (take in oxygen and give off CO2). 3. Circulation – have a circulatory system that transports wastes & nutrients/oxygen through body. 4. Excretion – have an excretory system that removes wastes from the body. 5. Response – respond to their environments using specialized cells called nerve cells (Nervous system).

9. Movement 6. Movement – all animals move at some point during their lives. Motile – animals that can move around, ex : jellyfish. Sessile – animals that don’t move around --- stay attached to a surface, ex : Sea anemones

10. Reproduction 7. Reproduction – may be sexual or asexual. Most are sexual – diversity. -Asexual reproduction in animals usually occurs as budding – outgrowth forms on the parent organism & then falls off & grows into a new organism. -Some animals are hermaphrodites - animals that have both male & female reproductive organs. -Other animals are capable of regeneration – process by which an animal grows a replacement for a missing body part.