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 following in order from simplest to complex : simplest to complex : cells tissues organs organ systems organisms

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

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

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

Reproduction & Cephalization 7. Can reproduce sexually or asexually 8. Have cephalization – concentration of sense organs & nerve sense organs & nerve cells at the front end cells at the front end of the body – a head. 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.

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.

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.

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).

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

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.