Worms 5 th Grade. 3 major Phyla Flatworms Roundworms Segmented worms.
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Transcript of Worms 5 th Grade. 3 major Phyla Flatworms Roundworms Segmented worms.
Worms
5th Grade
3 major Phyla
• Flatworms
• Roundworms
• Segmented worms
Characteristics of ALL worms
• Invertebrates
• Long, narrow bodies without legs
• Have head and tail ends
Do they have tissues, organs, and body systems?
• Yes! Unlike sponges and cnidarians, worms DO have tissues and organs
• Worms are the simplest organisms WITH A BRAIN
How does a worm’s brain and sense organs work?
• Sense organs can detect objects, food, mates, and predators quickly
• Sense organs that are sensitive to light, touch, and vibrations pick up information from the environment
• Brain interprets that information and directs the animal’s response
Example:
• A worm’s sense organ senses the vibrations of a footstep, and the brain tells the worm to quickly return to its underground burrow
Reproduction
• Worms have asexual and sexual reproduction depending on the species
• Some worms reproduce asexually by breaking into pieces.
• If you cut some kinds of worms into several pieces, a whole new worm will grow from each piece
What kind of symmetry to worms have?
• Bilateral Symmetry
1) Flatworms
• Flat
• soft like jelly
• Ex. Tapeworms, Planarians, Flukes
Flatworms CAN be parasites
• Parasite: an organism that lives inside or on another organism
• Parasites take food from their host
• Host: the organism that the parasite feeds on
Parasites:
• Rob their hosts of food • Make the hosts weak• May injure the host’s tissues or organs • Rarely kill host
• ALL flukes and tapeworms are parasites
Fluke
Flukes
• 10,000 species of flukes
• Range from .2 inches to 4 inches
Tapeworm
Tapeworms
• Attack the intestines
• Range from .04 inches to 50 ft
Planarians
• Free-living flatworms
• Free-living organism: does not live in or on other organisms
• Glide over rocks in ponds, slide over damp soil, swim slowly through the ocean
Planarians are scavengers!
• What is a scavenger?
Scavengers: organisms that feed on dead or decaying material
• Planarians feed like a vacuum cleaner
• Glide onto their food and insert a feeding tube into it
• Digestive juices flow out of the planarian and into the food, breaking down the food while it is still outside of the body
• Planarian sucks up the partly digested bits
Planarians are scavengers and predators
Either feed on dead or decaying food
Or
Attack any animals smaller than they are
Planarians
Planarians
• Size: usually between 1/8 of an inch to 1 inch
• Some tropical forms can be up to 2 ft!
Planarians
• Have 2 dots that look like eyes
• Eyespots: can detect light but cannot see a detailed image as human eyes can
• Planarian head also has cells that pick up odors
• Planarians rely mainly on smell, not light to locate food
Planarians
Tapeworm Life Cycle
• http://www.youtube.com/watch?v=EEBbtwGqPEs