Complex Invertebrates

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Complex Invertebrates
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Mollusks
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Characteristics

• Second largest phylum of animals
• 1. Soft body
• 2. Hard shells
• 3. Most have bilateral symmetry
• 4. Most live in salt water, some in fresh water
  and some on land
• 5. ALL have the same general body plan with a
  body cavity containing specialized cells and
  organs.

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Classes

• Gastropods
• Snails and slugs

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Mollusk classes

• Bivalves
• 2 shelled shellfish, clams, oysters

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Mollusks classes

• Cephalopods
• Squids and octopuses

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Body Parts

• 1. Muscular Foot- used to move
• Gastropods use it to secrete mucus
• 2. Visceral Mass contains the gills, gut and
  other organs
• 3. Mantle protects the body of mollusks that
  do not have a shell
• 4. Shell protects the mollusk from predators
  and keeps them from drying out.

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Open Circulatory System

• Found in gastropods and bivalves
• Definition A simple heart that pumps blood
  through blood vessels that empty into spaces in
  the animals body (sinuses)

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Closed Circulatory System

• Found in cephalopods
• Definition Heart circulates blood through a
  network of blood vessels that form a closed loop

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Complex Ganglia

• Control breathing, move food, control digestion.

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Annelid

• Segmented worms

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Characteristics

• Live in fresh water, in salt water or on land
• Have 100-175 segments
• Some segments are specialized for eating and for
  reproduction
• Nervous system includes brain and ganglia and
  nerve cord

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Characteristics continued

• Closed circulatory system
• Stiff bristles to help them move
• Scavenge anything edible or prey on other
  organisms as a predator of a parasite
• Eat soil and excrete wastes called casting

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Important to the soil

• 1. Casting provide nutrients that plants can use.
• 2. Burrowing tunnels allow air and water to
  reach deep into the soil

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Classes

• 1. Earthworms

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Classes

• 2. Bristle worms

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Classes

• Leeches
• -used for medical purposes
• -chemical that keeps blood from forming clots
• -prevent swelling

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Arthropods

• Largest group of animals
• (artho means jointed
• and
• pod means foot)

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Characteristics

• Jointed limbs
• Segmented body with specialized parts
• -parts head, thorax, abdomen
• Exoskeleton made of protein and chitin
• -protection
• -allows an organism to live on land and not
  become dried out.
• Well developed nervous system
• Compound Eye
• Antennae-feelers that respond to touch, taste and
  smell

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Arthropod Classes

• Crustaceans
• -include Shrimp, barnacles, crabs and lobsters

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Arthropod Classes

• Arachnids
• Include spiders, scorpions, mites, ticks, daddy
  long legs

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Arthropod Classes

• 3. Centipedes and Millipedes

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Arthropod Classes

• Insects
• Metamorphosis

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Echinoderms

• spiny skinned

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Echinoderm Characteristics

• Live on the sea floor
• Adults have radial symmetry
• Some larva have bilateral symmetry
• Have an endoskeleton an internal skeleton
  similar to vertebrates
• Simple nervous system

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Water Vascular System

• Helps an animal to
• Move
• Eat
• Breathe
• Sense changes in the environment

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Echinoderm Examples

• Brittle Stars

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Echinoderm Examples

• Sea Urchins

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Echinoderm Examples

• Sand Dollar

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Echinoderm Example

• Sea cucumber

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Examples

• Brittle star
• Sea Urchin
• Sand Dollar
• Sea Cucumber