Worms

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Worms
Flatworms, Roundworms, and Segmented Worms
Science7
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Characteristics of Worms

• All worms share the following characteristics
• Invertebrates
• Long narrow bodies without legs
• Tissues, organs, and organ systems (with brain)
• Bilateral Symmetry (head and tail ends)
• Reproduction Sexual and Asexual
• 3 Cell Layers
• Ectoderm
• Mesoderm
• Endoderm

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3 Major Phyla of Worms

• There are 3 major phyla of worms
• Platyhelminthes Flatworms
• Nematoda Roundworms
• Annelida Segmented Worms

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Flatworms

• From 2 Greek words
• Platy means flat
• Helminthe means worm
• Simplest of all worms
• Flattened bodies
• Most are parasites and get food from host

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Flatworms 3 Types

• There are many kinds of flatworms
• Planarians
• Tapeworms
• Flukes

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Flatworms Tapeworms

• Tapeworms
• Lives in the intestines of animals (including
  humans!)
• Uses hooks and suckers on its head to dig into
  the lining of an organisms digestive tract
• Considered Parasitic
• Blocks the hosts intestines
• Steals valuable food and water
• Can grow 10-12 meters in length

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Life Cycle of A Tapeworm
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Flatworms Planarians

• Planarians
• Scavengers
• A feeding tube releases digestive juices to break
  down food.
• THINK! What type of digestion is this?
• Odor cells are found on the head
• THINK! What do the odor cells help with?
• Planarians have 2 photosynthetic eyespots
• THINK! What do the eyespots detect?

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Flatworms Flukes

• Flukes
• Usually live in the human liver
• Shape Oval and flat
• Size 2mm -15 cm

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Activity Draw A Flatworm

• Draw, color, and label the diagram of this
  flatworm in your guided notes.

Mouth
Digestive Tract
Muscular Tube for Feeding
Nerve Tissue
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Roundworms

• General Characteristics
• Cylindrical bodies
• Contains a digestive system
• Food enters at a mouth
• Waste exits through the anus

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Roundworms Trichinella

• Trichinella
• Lives in muscular tissue of pigs
• These worms reproduce in the intestine of the
  host
• Female worms release hundreds of immature worms
  carried in the bloodstream
• These immature worms burrow in the surrounding
  tissue causing pain to the host

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Roundworms Hookworms

• Hookworms
• Enter the body by burrowing through the soles of
  feet
• Eventually ends up in the intestines where they
  live off of blood

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Roundworms Pinworms

• Pinworms
• Small white parasitic worms found in the feces of
  babies
• Babies sometimes ingest microscopic eggs from the
  soil

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Activity Draw A Roundworm

• Draw, label, and color this diagram of a
  roundworm in your guided notes. Compare it to a
  cnidarian which we just learned about.

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Segmented Worms

• Characteristics
• Annelida is Latin for Little Rings
• Body is made of many segments
• An earthworm has more than 100 segments!
• Organs are found within the segments

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Segmented Worms Closed Circulatory System

• Closed Circulatory System
• Blood moves within a confined set of blood
  vessels
• Five hearts are located in segments 5-13

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Segemented Worms Earthworms

• How they live
• They tunnel for a living
• They are scavengers eating dead plant and animal
  remains
• They crawl by using stiff bristles to pull
  themselves along

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Segmented Worms Earthworms

• Earthworms and Soil
• Earthworms make soil more fertile
• Their tunnels help loosen the soil and allow air,
  water, and plant roots to move through it.

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Activity Draw a Segmented Worm

• Draw, color, and label this diagram of a
  segmented worm in your guided notes.