 As animals evolved, they became increasingly more complex. Ex)cells tissues  To survive, all animals must perform the same function: Body support, feeding and digestion, respiration, excretion, internal transport, response.

 Kingdom: Anamalia *97% of the animal kingdom are classified as invertebrates ↓ Lack of backbone,verebral column, or spine.

 The common ancestors of all multicellular animals had already evolved two distinct layers separated by a jelly like middle layer. → Outer layer is called the ectoderm. ↓  This develops into skin and other body coverings and also gives the rise to the nervous system.

 The inner cell layer is called the endoderm. → grows into the tissues and organs of the digestive tract.  Most animals have a middle layer called the mesoderm. → skeleton and muscles.  A 2 nd important evolutionary trend in the invertebrates is the existence of a mesoderm lined cavity. ↓ This body of cavity is called a coelom.

 An opening or body cavity provides an open space inside the body for growth.  Animals that have a coelom are called coelomates.  A 3 rd important evolution trend in the invertebrates is the evolution of a body plan that is built up from several body compartments, or segments. ↓ These increase body size and adds specialization.

1. Most primitive of all living multicellular animals. 2. Phylum porifera. 3. Most live in marine environments.

1. Jelly fish, corals, sea anemones, and hydras 2. Phylum cnidaria 3. Mostly marine 4. Radial symmetry ↓ p. 449 Figure 19-9

 Flat worms  Phylum plathelminthes  Bilateral symmetry (left and right sides when cut down the center)  Shows Cephalization (they have a front end that resembles a head)

Mollusks 1. Clams, snails, and squids 2. Phylum mollusca Annelids 1. Segmented worms 2. Phylum annedlida 3. Earthworms 4. Recycle decaying organic matter

Echinoderms 1. Starfish, sea urchin, and sea lilies 2. Phylum echinodermate 3. Live entirely in H2O part radical symm. Arthropods 1. Largest and most diverse animals 2. Jointed-legs 3. Phylum arthropoda 4. Possibly 10 million species 5. External skeleton and joined legs 6. 3 largest groups. A)chelicerates B)crustaceans C)insects

Chelicerata 1. Spiders and scorpions 2. Named for mouth part chelicerae 3. Carnivores 4. Some poisonous Crustacea 1. Lobsters, shrimps, and crabs 2. Live in H2O Insecta → Half of all living things belong to the insects

1. Show a link between terrestrial animals with backbones and ancient ancestors in the sea. 2. Phylum-chordata 3. Endoskeleton with a stiff rod called a notochord (to which muscles are attached) 4. Found in marine environment.

There are 3 types of skeletons found in the animal kingdom are : 1. Hyrdostatic 2. Exoskeleton 3. Endoskeleton

 H2O- filled body cavity surrounded by muscles  This type of skeleton does not allow fast movement.

Exoskeleton External skeleton represented by the arthropods. Made up of chitin. The shells of the exoskeleton must be shed as the animal grows. Endoskeleton 1. Skeleton that is located within the body. 2. ex) Vertebrates.

 Intracellular digestion Food is digested inside the cells. The food is filtered from H2O by sponges.  Gastro Vascular Cavity Ex)cnidarians and flat worms is a digestive sac with only a single opening to the outside Food enters the opening and wastes leave through the same opening.

 Digestion takes place outside the cells.  Highly evolved digestive systems. → two openings (mouth and the anus)  “ Tube –within-a-tube” body plan

Internal Transport Two types of circ. System 1. Open circ. System 2. Closed circ. System *oxygen and nutrients, must be spread through the body; CO2 and wastes must be eliminated. Open circ. System blood from the heart isn't entirely contained in blood vessels. Blood is pumped and pumped into tissues and collects in openings called sinuses.

 Blood is contained in a system of closed vessels that pass through various parts of the body and return the blood back to the heart.  This system provides a more rapid and efficient control of the blood flow through the body.

- Some soft-bodied animals may be able to exchange O2 and CO2 with their environment simply by diffusion through their skin. 1. The resp. system must have a large surface area that is in contact with the environment 2. All resp. organs must keep their gas exchange surfaces wet. 3. Some organisms have gills→ feathery structures that expose a large surface area to the environment. 4. Spiders use book lungs. 5. Trachea(air filled tubes) are found in insects.

Process of eliminating toxic waste products. Helps maintain H2O balance. - Cells that break down amino acids produce a highly toxic H2O soluble waste product called ammonia. 1. Fresh H20 flatworms have excretory systems containing flame cells→ remove H2O and ammonia. 2. Annelids have structures called nephridia. 3. Insects have structures called Malpighian tubules.

Asexual Reproduction 1. Regeneration- regrowing of lost body parts ex) sponges 1. Budding- parent organism grows a bud that becomes an identical individual.

1. Have both male and female reproductive organs. 2. Produce both sperm and eggs. 3. *no self-fertilization 4. Ex)mollusks and annelids

1. External fertilization occurs when eggs and sperm meet outside the organisms body ex)trout 2. Internal fertilization takes place inside the body of the egg-producing individual. The sperm must find its way into the other body.