Porifera and Cnidarians

Porifera Sponges are the simplest found in this phylum There are about 10,000 species of sponges and they are all aquatic Asymmetrical and only have specialized cells

Sponges

Digestion and Feeding Filter feeders Sift plankton through collar cells Food is digested in a central cavity Clean up ocean floor Amebocytes, which are crawling cells, also help in feeding by distributing nutrients throughout the sponge.

Respiration All sponges perform respiration through their cell walls

Circulatory Sponges handle transportation by moving things through their body wall. Amebocytes (crawling cells) also distribute nutrients throughout the Porifera’s body

Excretion Through an osculum (a large opening) Amebocytes also transport CO2 and waste products through the osculum

Response They release protective chemicals, like toxins, to discourage predators

Movement Contain no nerves or muscles They are sessile (meaning that they are attached to the floor) Swimming larva are carried by currents before settling down and forming a new sponge. Skeleton composed of spongin (soft)  and spicules (hard)

Reproduction Reproduce sexually (sperm and eggs) Most sponges are hermaphrodites, and self fertilization is AVOIDED by producing sperm and egg cells at different times. Reproduce asexually (regeneration) budding

Cnidarians jellyfish, coral, hydra, sea anemone Named after the stinging cells found on their tentacles called CNIDOCYTES Radial symmetry Have two body forms: Polyp (vase shaped) Medusa (bowl shaped)

Jellyfish Sea Anome Coral Hydra

Feeding and Digestion Most are carnivorous. They have stinging tentacles called nematocysts. Digestion takes place in their gastrovascular cavity.

Respiration Passes nutrients through cells by diffusion

Circulatory Their “skin” contains three layers; the epidermis, the mesoglea and the gastroderm. They also have two germ layers

Excretion Through their mouth Done by diffusion

Response Nervous system is build up of nerve nets Corals produce poisons to protect themselves. These poisons are used in cancer research and poison research.

Movement Non-swimming larva and swimming medusa Hydrostatic skeleton that allows the them to change shape

Reproduction Sexual (medusa stage) Asexual (polyp stage) Release sperm, zygote develops on the females. Hermaphrodites: they can fertilize themselves because they contain both male and female reproductive organs Asexual (polyp stage) Budding

Flatworms Members of the phylum Platyhelminthes First phylum to have three germ layers: Ectoderm Mesoderm Endoderm Simplest animal with bilateral symmetry Three classes of flatworms

Feeding Most are parasitic Free-living : carnivores or scavengers; they have a digestive cavity, mouth and pharynx. Food is ingested through a muscular tube called the pharynx Tapeworms have a hook and sucker that enables it to attach a host

Respiration and Circulation Diffusion through the body wall Thin bodies allow for materials to diffuse (respiration, excretion, etc) Flame Cell – specialized cells that remove excess water

Response Ganglia – group of nerve cells that control the body (like a brain) Eyespot – group of cells that can detect light (like an eye)

Movement Flatworms move in 2 way: Cilia helps them glide through the water Muscle cells help them twist and turn

Reproduction Sexual Reproduction – most flatworms are hermaphrodites (have both male and female sex organs) Asexual Reproduction by fission  flatworms can split in two and regenerate Zygotes are passed out through the feces.

Roundworms Members of the phylum Nematoda Unsegmented worms Pseudocoelom (false coelom)

Feeding and DIgestion Can be: Free-living – predators Parasites - humans and animals Digestive tract with 2 openings: mouth & anus

Respiration and Circulation

Excretion Nitrogenous waste is excreted in the form of ammonia through the body wall

Response

MOvement

Reproduction Sexual reproduction,  Separate sexes