1 / 11

Flatworms, Roundworms, & Rotifers

Flatworms, Roundworms, & Rotifers. Chapter 34. Phylum Platyhelminthes. Section 34.1. General Structure:. 3 germ layers – ectoderm, mesoderm, and endoderm acoelomates Bilateral symmetry Anterior and posterior ends Dorsal and ventral surfaces only Flat body plan Flatworms!.

posy
Download Presentation

Flatworms, Roundworms, & Rotifers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Flatworms, Roundworms, & Rotifers Chapter 34

  2. Phylum Platyhelminthes Section 34.1

  3. General Structure: • 3 germ layers– ectoderm, mesoderm, and endoderm • acoelomates • Bilateral symmetry • Anterior and posterior ends • Dorsal and ventral surfaces only • Flat body plan • Flatworms!

  4. General Functions: • Exchange oxygen and carbon dioxide directly with the environment to cells by diffusion • No circulatory system or respiratory system needed • Only one opening where food and wastes pass through! • Cephalization

  5. Classification: • Four Classes: • Turbellaria - non-parasitic • Trematoda- parasitic • Monogenea - parasitic • Cestoda–parasitic

  6. 1. Class Turbellaria: • 4,500 species • Mostly marine • Swim in wavelike motion • Glide over solid surfaces on layer of mucus • Example: Planarian Dugesia • freshwater Video

  7. Planarian Body Plan:

  8. Planarian Organ Systems: Digestive System: • Scavengers & predators • Decaying plants & animal matter • Prey on smaller organism • Pharynx – throat that extends to the middle of body • video Pharynx

  9. Planarian Organ Systems: Excretory System: • Flame Cells – enclosed tufts of cilia that draw excess water together and excretes it through pores • video Flame Cells

  10. Planarian Organ Systems: Nervous System: • Cerebral ganglia: two clusters of nerve cells at anterior • “Brain” • Can learn • Eyespots: sense direction and intensity of light • Other senses: touch, water currents, chemicals

  11. Planarian Organ Systems: Reproductive System: • Sexual: • Hermaphrodites • Eggs laid in protective capsule • Hatch in 2-3 weeks • Asexual: • Regeneration • video Video

More Related