Worms

1. Worms Chapter 1 Section 4

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

3. 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

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

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

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

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

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

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

10. 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

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

12. 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

13. Reproduction • How do worms reproduce? • 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

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

15. Flatworms • Most are parasites that obtain food from their hosts • Parasite: • 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

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

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

18. 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

19. Planarian • Feeds like a vacuum cleaner • 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

20. 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

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

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

23. 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

24. 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

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

26. 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

27. Segmentation • Ex: • 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

28. 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

29. 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

30. 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

31. 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

33. 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