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Chapter 26. Sponges, Cnidarians, Flatworms, and Roundworms. Phylum Porifera (Sponges). Characteristics: Simple body structure with no true tissues; multicellular, ( hermaphrodites —animal has both male and female structures), asymmetrical
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Chapter 26 Sponges, Cnidarians, Flatworms, and Roundworms
Phylum Porifera (Sponges) • Characteristics: • Simple body structure with no true tissues; multicellular, (hermaphrodites—animal has both male and female structures), asymmetrical • Sessile—no movement as adults; are filter feeders (catch food as it floats through them) • Have pores that absorb water • Spicules—tiny hard particles of calcium or silicon compounds that make up skeleton
Phylum Porifera (Sponges) • Reproduction: can be asexual (budding) or sexual by releasing sperm that enters other sponges through pores where it will fertilize the egg. • After fertilization, larvae will develop. Larvae are immature stages of an animal.
Egg cell Sperm cells Flagella Larvae New sponge Sponge Reproduction
Review Questions 1. What word means that a sponge does not move? Sessile 2. How do sponges eat? By filtering the water around them 3. What tiny, hard particles make up the sponge skeleton? Spicules
Mouth Tentacle Cavity Inner cell layer Jellylike layer Bud Outer cell layer Disc Phylum Cnidaria and Cnetophora • Characteristics • Radial symmetry with true tissues; cup/bell shaped • Have stinging cells called nematocysts to help capture food • Sting can be fatal to humans • examples: hydra (very tiny jellyfish-like animal), jellyfish, coral, sea anemones Has one body opening made of two layers of cells
Polyp Medusa Body Form of Cnidarians • Has 2 life forms during their life cycle: • Polyp- has a tube-shaped body with a mouth surrounded by tentacles. • Medusa- has an umbrella-shaped body called a bell.
Reproduction in Cnidarians • Reproduction:Sexually and asexually through budding
Review Questions 1. What type of symmetry do cnidarians have? Radial 2. What are nematocysts? Stinging cells 3. Give an example of a cnidarian. Coral, jellyfish, sea anemone, hydra 4. What are the 2 life forms of a cnidarian? Polyp & medusa
Phylum Platyhelminthes “Flatworms” • Characteristics • Simplest animal with bilateral symmetry; have long, thin flat bodies. Usually hermaphroditic. • Many are parasitic (ex: tapeworms, liver flukes)
Phylum Platyhelminthes “Flatworms” • Reproduction • Usually hermaphroditic and reproduce sexually. During mating, they fertilize each other at the same time. • Some can reproduce asexually by regenerating (regrowing) lost parts. (ex: cut planarian: will grow back lost parts!)
Adult flukes Larva Embryos released Human host Snail host Larva Life Cycle of a Flatworm
Phylum Nematoda “Roundworms” and Rotifera • Characteristics • Bilateral symmetry, have both mouth and anus • Live in soil, fresh and marine water. • Nematodes: roundworms that are often parasitic • Examples: Ascaria (intestinal roundworm about 1 ft long), hookworms, trichinella (from undercooked pork), pinworms, heartworms
Phylum Nematoda “Roundworms” and Rotifera • Reproduction • Most have separate sexes. Lay eggs.
FYI: Roundworm parasites of humans • Hookworm infections are common in humans in warm climates where they walk on contaminated soil in bare feet. • Hookworms cause people to feel weak and tired due to blood loss.
FYI: Roundworm parasites of humans • Pinworms are the most common human roundworm parasites in the United States. • Pinworms are highly contagious because eggs can survive for up to two weeks on surfaces.
FYI: Ascaris • Eggs of Ascaris are found in soil and enter a human’s body through the mouth. Ascaris worm coming out of a pig.
Beard worm Christmas tree worm Phylum: ANNELIDA “Segmented worms” - Also have: (turn to pink sheet) • Setae—external bristles for movement • Coelom—true fluid-filled body cavity • Ex: Earthworms, leeches • Earthworms loosen soil and make it better for growing plants • Reproduction • Sexual: hermaphrodites (have sperm and eggs), cannot fertilize themselves. • Description: (PG.16 Purple Sheet) • Bilateral symmetry, segmented body, closed circulation (have vessels) and true digestive system, oxygen diffuses through skin
Phylum: ANNELIDA “Segmented worms” Earthworm CHARACTERISTICS: Body Temp - Ectothermic Symmetry - Bilateral Digestive System – Complete Skeletal System – None Circulatory System – Closed Reproductive System – Sexual Heart Chambers – Heart Body Leeches
Class Gastropoda (snails & slugs)…2nd largest class after Class Insecta • Class Bivalvia “Bivalves” (scallops, oysters, clams, mussels) • Class Cephalopoda (squid & octupi)…Only mollusks with brains! Mollusks
Phylum: MOLLUSCA *from Latin word, “molluscus” - soft Description: *2ND Largest Phylum of Animals • 3 Main Body Parts: 1. Muscular foot 2. Head 3.Visceral mass (its insides) • FYI: terrestrial and marine • Reproduction • Sexual: most have separate sexes, produce gametes Giant clam Sea Slug
Phylum: MOLLUSCA Squid CHARACTERISTICS: Ectothermic Symmetry - Bilateral Digestive System – Complete Skeletal System – None Circulatory System – *OPEN* Reproductive System – Sexual Nervous System - Simple Heart Chambers - 2 or 3 in some Nautilus octopus
Subphylum Crustacea (lobsters, crabs, crayfish…GILLS) • Class Insecta (all insects have 6 legs) • Class Arachnida (spiders & scorpions…all have 8 legs) • Class Diplopoda (millipedes) • Class Chilopoda (centipedes) Arthropods
Phylum: ARTHROPODA “Arthropods” Crabs • Description: • Have segmented appendages (joints) that allow for flexibility • Molting—since exoskeletons do not grow, arthropods have to shed exoskeleton and form new one Bull Ant
Phylum: ARTHROPODA “Arthropods” Crabs • Description: • Mandibles—mouthparts for holding, chewing, sucking, biting • Have segments fused into three main body sections: head, thorax, abdomen; a fusion of the head & thorax = cephalothorax Bull Ant
Oxygen obtained through: gills, tracheal tubes, or lungs • Metamorphosis—series of 4 changes in shape and body structure during development. • Incomplete metamorphosis—only has 3 stages; once such an insect hatches, it looks almost like the adult version and is called a nymph
Locust molting CHARACTERISTICS: Body Temp - Ectothermic Symmetry - Bilateral Digestive System – Complete Skeletal System – Exoskeleton Circulatory System – Open Reproductive System – Very diverse Nervous System - Simple Heart Chambers – Muscular Tube “Evil” Butterflies Lobster
The Arachnids: Ticks & Mites Tick American House Mites
Spiny Cushion Sea Star Description: • Move with tube feet—appendages with suction cups on tips • FYI: Have mouth, stomach, intestines, but no head/brain • All echinoderms have exoskeletons made of calcium carbonate. • Reproduction • Sexually with gametes, asexually with regeneration Feather Star Egyptian Sea Star Sand Dollars
Phylum: Echinodermata “Echinoderms” CHARACTERISTICS: Body Temp - Ectothermic Symmetry - Radial Digestive System – Complete Skeletal System – Exoskeleton Circulatory System – Open Reproductive System – Sexual & asexual Heart Chambers – No true heart