26-2 Sponges - cypresswoodsbiology
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What Is an Animal?
• What Is an Animal?
• Animals are multicellular, eukaryotic heterotrophs whose cells lack cell walls.
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What Is an Animal?
• Invertebrates make up 95% of all animal species.
• Invertebrates do not have a backbone, or vertebral column .
• They include sea stars, worms, jellyfishes, and insects.
26-2 Sponges
Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall
What is a Sponge?
• What is a Sponge?
• Sponges are in the phylum Porifera which means “pore-bearers .”
• Sponges live their entire adult life as sessile organisms; attached to a single spot .
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Form and Function in Sponges
• Body Plan
• Sponges are asymmetrical ; they have no front or back ends, no left or right sides.
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Form and Function in Sponges
• Feeding
• Sponges are filter feeders .
• As water moves through the sponge, food particles are trapped and engulfed by choanocytes that line the body cavity.
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Form and Function in Sponges
• Circulation
• Sponges rely on movement of water through their bodies to carry out body functions.
Branching Tube Sponge
Stove Pipe Sponge
Vase Sponges
Barrel Sponges
Ball Sponges
Rope
Sponges
26-3 Cnidarians
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Copyright Pearson Prentice Hall
What is a Cnidarian?
• What is a Cnidarian?
• Cnidarians are soft-bodied , carnivorous animals that have stinging tentacles arranged in circles around their mouths.
They are the simplest animals to have body symmetry and specialized tissues.
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What is a Cnidarian?
• Within each cnidocyte is a nematocyst —a poison-filled, stinging structure that contains a tightly coiled dart.
Trigger
Filament
Nematocyte
Barb
Filament
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Form and Function in Cnidarians
• Form and Function in Cnidarians
• Cnidarians are radially symmetrical . They have a central mouth surrounded by numerous tentacles that extend outward from the body.
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Form and Function in Cnidarians
• Feeding
• A cnidarian pulls its food through its mouth and into its gastrovascular cavity , a digestive chamber with one opening.
• Food enters and wastes leave the body through that same opening .
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Form and Function in Cnidarians
• Circulation
• Following digestion, nutrients are usually transported throughout the body by diffusion .
Portuguese man-of-war
• Colonial Hydrozoan
(not a single organism
• Tentacles sting prey such as fish & humans
• Polyps in colony feed
• Has gas-filled air float copyright cmassengale 25
Anthozoans copyright cmassengale 26
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Hydra Feeding
27
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Food in
Gastrovascular
Cavity
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Scyphozoans
Some Jellyfish Show
Luminescence
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27 –1 Flatworms
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Copyright Pearson Prentice Hall
What Is a Flatworm?
• Flatworms are acoelomates , which means they have no coelom .
• A coelom is a fluid-filled body cavity that is lined with tissue derived from mesoderm .
• The digestive cavity is the only body cavity in a flatworm.
• Flatworms have bilateral symmetry .
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Form and Function in Flatworms
• Feeding
• Flatworms have a digestive cavity with a single opening through which both food and wastes pass .
• Near the mouth is a muscular tube called a pharynx .
• Flatworms extend the pharynx out of the mouth. The pharynx then pumps food into the digestive cavity.
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Form and Function in Flatworms
• Circulation
• Flatworms do not need a circulatory system to transport materials they rely on diffusion
Tapeworm
Anatomy
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Copyright Pearson Prentice Hall
27 –2 Roundworms
Roundworms
ROUNDWORMS
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What Is a Roundworm?
• Roundworms are unsegmented worms that have pseudocoeloms and digestive systems with two openings —a mouth and an anus.
• Roundworms have bilateral symmetry.
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Form and Function in Roundworms
• Feeding
• Many free-living roundworms use grasping mouthparts and spines to catch and eat other small animals.
• There are a variety of parasitic roundworms as well
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Form and Function in Roundworms
• Circulation
• They depend on diffusion to carry nutrients and waste through their bodies.
Cysts in Contaminated Pork
27-3 Annelids
Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall
What Is an Annelid?
• What Is an Annelid?
• Annelids are worms with segmented bodies .
They have a true coe lom that is lined with tissue derived from mesoderm.
• Annelids have bilateral symmetry .
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Form and Function in Annelids
• Feeding and Digestion
• In carnivorous species, the pharynx usually holds two or more sharp jaws that are used to attack prey.
• Annelids that feed on decaying vegetation have a pharynx covered with sticky mucus.
• Other annelids obtain nutrients by filter feeding.
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Form and Function in Annelids
• Circulation
• Annelids typically have a closed circulatory system, in which blood is contained within a network of blood vessels .
Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall
