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Worms Chapter 1 Section 4.

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Presentation on theme: "Worms Chapter 1 Section 4."— Presentation transcript:

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

4 Flatworms

5 Flatworm

6 Roundworm

7 Segmented Worms

8 Segmented Worms

9 Segmented Worms

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? 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

14 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

15 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

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 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

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

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

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: 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

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

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

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