Worms Chapter 1 Section 4

What Worms have in Common What are the 3 major phyla of worms we are discussing? Flatworms Roundworms Segmented worms

Flatworm http://img.ehowcdn.com/article-new/ehow/images/a05/70/fq/symptoms-tapeworms-horses-800x800.jpg http://www.astrographics.com/GalleryPrints/Display/GP2104.jpg

Flatworms http://aapredbook.aappublications.org/content/1/SEC131/SEC269/F2258.large.jpg http://www.freeendlessinfo.com/wp-content/uploads/2012/04/caninetapeworms.jpg

Flatworm http://www.daviddarling.info/images/flatworm_section.jpg http://upload.wikimedia.org/wikipedia/commons/2/2a/NZ_Flatworm.JPG

Roundworm http://www.petsandparasites.org/images/uploads/images/AscaridInIntestine.gif

Segmented Worms http://www.arcodiv.org/seabottom/images/orange_ploychaet_400x300.jpg http://www.emc.maricopa.edu/faculty/farabee/biobk/annelidbody.gif

Segmented Worms http://ichef.bbci.co.uk/naturelibrary/images/ic/credit/640x395/a/an/annelid/annelid_1.jpg

Segmented Worms http://www.historyforkids.org/scienceforkids/biology/animals/segmentedworms/pictures/earthworm.jpg

What Worms have in Common Which phylum do flatworms belong to? Platyhelminthes Which phylum do roundworms belong to? Nematoda Which phylum do segmented worms belong to? Annelida

What Worms have in Common Invertebrates Long, narrow bodies without legs Have tissues, organs, and organ systems Bilateral symmetry Head and tail end

Worms Do worms have a brain? Yes Simplest organism with a brain Knot of nerve tissue located in the head end Detect food, mates, and predators quickly Responds to the information from the brain

Reproduction How do worms reproduce? Regeneration : Sexually Male and female worms = sexually Have both sex organs – 2 worms mate and exchange sperm Break into pieces – asexually Earthworms can’t do this Regeneration : Ability to regrow body parts

Flatworms Flat bodies Examples: Bodies soft like jelly Planarians Flukes Tapeworms Bodies soft like jelly Almost too small to be seen except tapeworms can grow to 12 meters

Flatworms Most are parasites that obtain food from their hosts Organism that lives inside or on another organism Host: The organism that a parasite lives on or in The parasite takes nutrients from the host

Tapeworms 1 kind of parasitic flatworm Absorbs food from the host’s digestive system Most live in more than 1 host during their lifetime

Planarian Nonparasitic flatworm Glide over rocks, damp soil, and swim slowly through oceans Scavengers: Feed on dead or decaying material

Planarian They also are predators towards animals smaller than they are Have eyespots Function sort of like eyes but can not see specific images Head has cells to pick up odors Use smell to locate food

Planarian Feeds like a vacuum cleaner Sucks up partly digested food Inserts a feeding tube into its food Sucks up partly digested food Distributed to body cells by diffusion Only have 1 opening Undigested food leaves through the feeding tube

Roundworms Million roundworms live in each square meter of sand Live in moist environment Tiny and hard to see May be the most abundant animal on Earth

Roundworms Cylindrical body Tiny strands of spaghetti Can be carnivores, herbivores, or parasites Hookworms are a roundworm parasite

Hookworm http://www.foxvalleyvet.net/wordpress/wp-content/uploads/2011/09/hookworm2.jpg

Roundworms Have a digestive system that is open at both ends Waste exits through the anus Having a one-way digestive system allows the worm to use its food efficiently and absorb more nutrients

Segmented Worms You can find them in your own backyard Leeches are parasitic segmented worms More closely related to crabs and snails http://news.discovery.com/human/2010/11/12/leech-278x225.jpg

Segmented Worms Occupy nearly all environments Use burrows to hide from predators Sit-and-wait predators

Segmentation Bodies are made up on many linked sections called ___________ Segments Earthworms usually have more than 100 segments Some organs are repeated in most segments

Segmentation Ex: 1 way digestive tract which means they have an anus Each segment has tubes that remove wastes Reproductive organs are found in only certain segments Nerve cords and the digestive tube run the whole length of the body 1 way digestive tract which means they have an anus

Closed Circulatory System Blood moves only within a connected network of tubes called blood vessels In an open system the blood leaves the circulatory system and sloshes inside the body A closed system can move the blood faster

Closed Circulatory System If you have a closed system you can be larger and more active Blood carries oxygen and food to cells http://www.infusion.allconet.org/webquest/img010.jpg

Earthworms Earthworms scavenge for Dead and decaying plant and animal remains in the soil When it is damp they come out of their burrows They only come out when it is damp because their skin can’t dry out

Earthworms They mainly come out at night because they are safer from predators Obtain oxygen through the moisture on their skin Bristles on the segments help the worms move

Earthworms Benefit us: Make the soil more fertile with their droppings Loosen soil when they tunnel Allow air, water, and roots to move through the soil when they tunnel