Presentation on theme: "Phyla of invertebrates include 1.Porifera 2.Cnidarian 3.Flatworms 4.Roundworms 5.Segmented worms 6.Mollusks 7.Arthropods 8.Echinoderms i n o r d e r o."— Presentation transcript:
Multicellular WITHOUT TISSUES Heterotrophic filter feeders No cephalization present Acoelomates Diploblastic-connected by noncellular mesogles Sessile animals that lack nerves or muscles. However, individual cells can sense and react to changes in the environment.
Porifera from Greek ”pore bearer” Aquatic, largely marine Respiration: Occurs over the entire surface of the organism wherever cells are in direct contact with the environment.
Body Plan Most are asymmetrical Harder sponges have spicules sponginSofter sponges have fibers made of a flexible protein called spongin. Modified collagen :Choanocytes provide structural support and deter predators
Sponge Spicules Spicules are the spiny skeleton of sponges –Secreted by specialized cells called Archaeocytes –Calcium Carbonate(CaCO 4 ) or Glasslike Silica (SiO 2 )
Feeding Feed by drawing water into the body through many pores and extracting food particles. Choanocytes- specalized cells with flagella.
Choanocytes pass the food to the amoebocytes, which wander between the two cell layers.
Larvae use flagella to swim to new location to become sessile adult Reproduction Asexual: New individuals bud from parents Parent sponge breaks into many pieces (Fragmentation) Sexual: Internal Fertilization Male releases clouds of sperm into water, and water currents carry sperm to female Some are hermaphrodites
Clip Ecology Habitat for marine animals Symbiotic relationships with green algae & bacteria.
All are aquatic Radial symmetry Corals, Jellyfish, sea anemones, hydras Rings of tentacles used to capture food and defend against prey Tentacles covered with nematocysts (stinging, harpoon-like structures that produce toxins that cause paralysis)
Have nerve cells- nerve net- that can sense the environment. Unlike highly organized nervous systems, this nerve net transmits impulses in several directions at once, which results in multiple firings of nematocysts in parts not directly stimulated. Can detect light through structures called ocelli.
Basic body plan-two variations: the sessile polyp and the floating medusa. Polyps-adhere to the substratum by the aboral end and extend their tentacles, waiting for prey. Medusas (also called jellies) are flattened, mouth-down versions of polyps that move by drifting passively and by contracting their bell-shaped bodies. Animation
Digestion Gastrodermis (cells that line the gastrovascular cavity) secretes digestive enzymes into the gastrovascular cavity. Food particles then engulfed by cells.
Respiration: Occurs over the entire surface of the organism wherever cells are in direct contact with the environment.
All Cnidarians have Cnidocytes cnidocytes on the tentacles defend the animal or capture prey. Organelles called cnidae evert a thread that can inject poison into the prey, or stick to or entangle the target. Cnidae called nematocysts are stinging capsules.
Feeding Paralyzes the prey and then pulls it through its mouth into its gastrovascular cavity where digestion takes place. Waste is excreted through the mouth.
Can also be filter feeders Some live in symbiosis with autotrophic algae -Cassiopeia
Cnidocytes: Stinging in Action Specialized Stinging Cells called Cnidocytes which contain nematocyst in tentacles –When triggered by touch or chemicals; shoot harpoon like barb into victim –Also release toxin
Reproduction and Life Cycle Have two life stages Sexes are generally separate Three types: 1) Medusa form dominates 2) Polyp form dominates 3) Solely polyp form
Classes of Phylum Cnidaria Scyphozoa- Jellyfish Medusa form dominates “Cup-Animal”
Class Hydrozoa includes hydras and Portuguese man- of-war (Physalia). a. The polyp stage is dominant. b. Portuguese man-of-war is a colony of polyps; original polyp is a gas- filled float. c. Other polyps specialize for feeding or reproduction. d. Can cause serious injury to swimmers with a tentacle having numerous nematocysts; each tentacle arises from the base of each feeding polyp. Obelia
Anthoaoz-Sea Anemones, corals Only a polyp stage “Flower-Animal” a. Sea anemones are solitary polyps 5-100 mm in height and 5-200 mm in diameter or larger. b. Many are brightly colored and resemble flowers. c. A thick, heavy body supports a mouth surrounded by hollow tentacles. d. Sea anemones feed on invertebrates and fish. e. They attach to rocks, timbers, etc., or may be mutualistic and attached to a hermit crab's shell. f. Corals may be solitary; most are colonial. g. Most live in shallow waters; accumulation of their calcium- carbonate remains builds reefs.
In order for the Clownfish to live within the tentacles of the sea anemone, it must develop immunity to the stinging cells of the anemone. It does this by touching one or two tentacles at a time, over time the number of tentacles touched are numerous and eventually the fish creates mucus that protects it from the sting cells of that specific sea anemone. Once the clownfish does create a relationship with an anemone, it must stay with that specific anemone, because the stinging cells of individual sea anemones are different.