Sponges and Cnidarians

Animal Kingdom and SpongesClassification of living thingsEubacteriaArchaebacteria Protisita FungiPlantaeAnimaliaIntroduction to the Animal KingdomMembers of the animal kingdom share certain characteristics:

MulticellularEurkayoticLack cell wallsHeterotrophs-they obtain nutrients and energy by feeding on organic compounds from other organisms.The bodies of most animals contain tissues.Animals have epithelial, muscular, connective, and nervous tissues.Epithelial Tissues- cover body surfacesMuscle Tissue-contains proteins that enable the cells to contract moving parts of animals bodies.Connective Tissue- such as bone or blood, support an animals body and connective parts.Bone Tissue- produce minerals that give strength and hardness to the bone.Nervous Tissue- is composed of nerve cells, which have threadlike projections that act like telephone wires to carry information throughout the body.Invertebrates- animals that have no backbone or vertebral column. 95% of species.

Vertebrates- have a backbone (fish, amphibians, reptiles, birds, and mammals). Only 5% of species.What animals do to surviveAnimals must carry out the following essential functions to survive:FeedingRespirationCirculationExcretionResponseMovementReproductionFeedingMost animals cannot absorb food; instead they ingest (or eat) it.Herbivores-eat plantsCarnivores-eat other animalsOmnivores- eat both plants and animalsDetritivores-eat decaying plant and animal matter.RespirationAll animals whether they live in water or on land respire.Respire- take in oxygen and give off carbon dioxide.Circulation Many small aquatic animals, such as some aquatic worms, rely solely on diffusion to transport oxygen, nutrient molecules, and waste products among all their cells.

Other larger animals have some kind of circulatory system to move materials around within their bodies.ExcretionA primary waste product of cells in ammonia, a poisonous substance that contains nitrogen.Most animals have an excretory system that either eliminates ammonia quickly or converts it into a less toxic substance that is removed from the body.Excretory systems vary from cells that pump water out of the body to complex organs such as kidneysResponseAnimals respond to events in their environments using specialized cells called nerve cells.The arrangement of nerve cells in the body changes dramatically from phylum to phylum.MovementMost animals are motile meaning they can move.Muscle contraction enables motile animals to move around, usually working in combination with a support structure called a skeleton.ReproductionMost animals reproduce sexually by producing haploid gametes, which helps create and maintain genetic diversity in populations.Many invertebrates can also reproduce asexually. This allows animals to increase their numbers rapidly.

Trends in Animal EvolutionComplex animals tend to have high levels of cell specialization and internal body organization, bilateral body symmetry, a front end or head with sense organs and a body cavity.Cell specialization and levels of organizationGroups of specialized cells formTissues which formOrgans which formOrgan systems

All of which work together to carry out a variety of complex functionsEarly DevelopmentAnimals that reproduce sexually begin life as a zygote, or fertilized eggs.The zygote undergoes a series of division to form a blastula.

During early development, the cells of most animal embryos differentiate into three layers called germ layers.Endoderm- innermost germ layer, develop into the linings of the digestive tract and much of the respiratory system.Mesoderm-middle layer, gives rise to the muscles and much of the circulatory, reproductive and excretory organ systems.Ectoderm-outermost layer, gives rise to the sense organs, nerves, and outer most layer of the skin.Body SymmetryWith the exception of sponges, every kind of animal exhibits some type of body symmetry.Radial symmetry- similar to that of a bicycle wheel, in which any number of imaginary planes can be drawn through the center, each dividing the body into equal pieces.Bilateral symmetry- Such as a crayfish, only a single imaginary plane can divide the body into two equal halves. They have left and right sides.

Bilateral symmetryThe anatomy allows for segmentation, in which the body is constructed of many repeated and similar parts or segments. Animals with bilateral symmetry such as worms and insects, and vertebrates, typically have external body parts that repeat on each side of the body. The combination of bilateral symmetry and segmentation is found in two of the most successful animal groups- arthropods and vertebrates.CephalizationCephalization- is the concentration of sense organs and nerve cells at the front end of the body. Animals with cephalization respond to their environment more quickly and in more complex ways than simpler animals can.

Body Cavity FormationFluid filled space that lies between the digestive track and body wall.It provides space in which internal organs can be suspended so that they are not pressed on by muscles or twisted out of shape by body movements. Allow for specialized regions to developProvide room for internal organs to grow and expand.Sponges

This Not ThatSpongesSponges are classified as animals because they are multicellular, heterotrophic, have no cell walls, and contain a few specialized cells.They have nothing resembling a mouth or gut, and they have no tissues or organ systems. Sponges are sessile (they live their entire life attached to one spot)In the phylum Porifera which means pore-bearers

Form and Function in spongesSponges carry out basic functions, such as feeding and circulation, by moving water through their bodies.Body planSponges are asymmetricalSponges have no front, back, left or right sides.They have a body that forms a wall around a large central cavity through which water is circulated continually.Choanocytes- are specialized cells that use flagella to move a steady current of water through the sponge.Osculum- a large hole at the top of the sponge where the water leaves.

The movement of water through the sponge provides a simple mechanism for feeding, respiration, circulation, and excretion.Sponges have a simple skeletonSpicule- a spike-shaped structure make od chalklike calcium carbonate or glasslike silica.Archaeocytes- specialized cells that move around the within the walls of the sponge and make spicules.Softer sponges have an internal skeleton make of spongin, a network of flexible protein fibers. These are the sponges that are harvested and used as natural bath sponges.FeedingSponges are filter feeders that sift microscopic food particles from the water.Digestion is intracellularAs water moves through the sponge, food particles are trapped and engulfed by choanocytes that line the body cavity. These particles are then digested or passed onto archaeocytes. The archaeocytes complete the digestive process and transport digested food throughout the sponge.

Respiration, Circulation and ExcretionAs water moves through the body cavity, oxygen dissolved in the water diffuses into the surrounding cells. At the same time, carbon dioxide and other wastes, such as ammonia, diffuse into the water and are carried away.ResponseSponges do not have a nervous system.Many sponges protect themselves by producing toxins that make them unpalatable or poisonous to potential predators.Example of sponges

Pink Sponge

Tube SpongeYellow Sponge

Painted Tunicate

Red Tree Sponge

Common Sea SquirtVase SpongeAnimation of a sponge