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Porifera and Cnidarians
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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
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Sponges
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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.
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Respiration All sponges perform respiration through their cell walls
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Circulatory Sponges handle transportation by moving things through their body wall. Amebocytes (crawling cells) also distribute nutrients throughout the Porifera’s body
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Excretion Through an osculum (a large opening)
Amebocytes also transport CO2 and waste products through the osculum
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Response They release protective chemicals, like toxins, to discourage predators
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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)
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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
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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)
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Jellyfish Sea Anome Coral Hydra
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Feeding and Digestion Most are carnivorous.
They have stinging tentacles called nematocysts. Digestion takes place in their gastrovascular cavity.
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Respiration Passes nutrients through cells by diffusion
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Circulatory Their “skin” contains three layers; the epidermis, the mesoglea and the gastroderm. They also have two germ layers
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Excretion Through their mouth Done by diffusion
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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.
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Movement Non-swimming larva and swimming medusa
Hydrostatic skeleton that allows the them to change shape
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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
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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
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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
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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
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Response Ganglia – group of nerve cells that control the body (like a brain) Eyespot – group of cells that can detect light (like an eye)
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Movement Flatworms move in 2 way:
Cilia helps them glide through the water Muscle cells help them twist and turn
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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.
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Roundworms Members of the phylum Nematoda Unsegmented worms
Pseudocoelom (false coelom)
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Feeding and DIgestion Can be:
Free-living – predators Parasites - humans and animals Digestive tract with 2 openings: mouth & anus
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Respiration and Circulation
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Excretion Nitrogenous waste is excreted in the form of ammonia through the body wall
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Response
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MOvement
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Reproduction Sexual reproduction, Separate sexes
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