Invertebrates

1. Invertebrates

2. Animal Characteristics • All organisms in this kingdom have these common characteristics: • Multicellular Eukaryotes • No cell wall- unlike fungi, plants, bacteria • Heterotrophs– consumer not decomposer • Have Specialized Cells- unlike protists

3. Needs of Animals • Need: Sense and chase down food source Adaptation: nervous / motor systems • Need: Break up food and absorb nutrients Adaptation: digestive system • Need: Deliver oxygen to all cells Adaptation: circulatory / respiratory systems

4. SYMMETRY • Asymmetry – no symmetry • Radial symmetry - can cut in equal halves-more than one way • Bilateral symmetry – allows for development of brain region in a central location (head)

5. Types of Symmetry Asymmetry

6. Asymmetry-Sponges Only

7. Radial Symmetry

8. Background: different types of body symmetry *Usually simpler organisms *Usually more complicated organisms

9. Bilateral Symmetry They all have a head area with sense organs

10. Development of Organisms • Develop from a single cell, the zygote • Mitosis forms new cell in a process called cleavage • A hollow ball of cells are formed called a blastula • Gastrulation is the folding in of the blastula to form two layers • These two layers are the ectoderm and the endoderm

11. Development

12. Development • Ectoderm develops into skin and nervous tissue • Endoderm develops into the lining of the digestive tract and organs associated with digestion • In some animals the gastrula forms a mesoderm • Mesoderm is the third layer and develops into muscles, circulatory, excretory, and respiratory systems

13. Development • Protostome is an animal with a mouth that develops from the opening in the gastrula called the blastopore • Deuterostome The anus develops from the opening in the gastrula

14. Body Plans • Acoelom- do not have a body cavity, organs are imbedded in tissues • Pseudocoelom -(partial) a body cavity partly lined with mesoderm • Coelom- a body cavity that provides space for the development of internal organs (something for muscles to push against to move)

15. *Background: types of coelomes (body cavities)

16. Vertebrate vs Invertebrate • Vertebrate- has a backbone • Invertebrate- has NO backbone

17. Exoskeleton • Functions: • Protection • Prevents water loss on land (waxy layer) • Problems: • Heavy • Growth requires molting

18. Exoskeletons

19. Endoskeleton • An internal skeleton that provides support inside the body • Advantage: Organisms can grow larger with skeleton inside

20. Endoskeletons

21. Sponges • Simplest Animals • Asymmetry

22. Sponges • Sessile - do not move • Asymmetrical • No tissue (Only organized cells)

23. Sponges • Oxygen and food come in through Diffusion • Filter Feeds as an adult

24. Sponge Reproduction • Sexual – release sperm into water (external fertilization very common in aquatic animals) • Hermaphroditism – sponges have sperm AND eggs to increase the odds of reproduction • Offspring can swim to a new location • Asexual fragmentation also possible

25. Cnidarians Sea Anemone (Polyp) Jellyfish (Medusa)

26. Cnidarians • Evolution of Radial Symmetry • Extends tentacles equally in all directions (increase food uptake)

27. Cnidarian Characteristics • Basic digestive system • Also basic nervous system (nerve net) • O2 still enters by diffusion

28. Cnidarian Characteristics • Reproduces sexually and asexually • Skeleton-none present, but dead coral remains are calcium carbonate

29. Body Plans of Cnidarians

30. Flatworms-Platyhelminthes Planarian – not parasitic Tapeworm – parasitic

31. Flatworm Characteristics • No coelom – Why? Many are parasitic • O2 and sugar are absorbed in host’s intestine • Bilateral symmetry • Reproduction-most are hermaphrodites

32. Tapeworms

33. Tapeworm Life Cycle

34. Flatworm or Planaria Fresh Water Planaria Uses Pharynx to obtain food Salt Water Flatworms

35. Sheep Liver Fluke

36. Roundworms hookworm - parasitic

37. Roundworms • Smooth, non-segmented body • Pseudocoelom (moves more) • Can burrow through skin (walking around barefoot) • Also enters through contaminated food

38. Roundworm CharacteristicsMore Advanced • Bilateral symmetry • Complete digestive system with mouth and anus • Sexual reproduction • Oxygen enters by diffusion

39. Hookworms, Pinworms, Tapeworms that were removed from a Brazilian boy treated on a Rockefeller foundation mission (early 1900’s) These parasites still affect people all over the globe.

40. Not a problem in U.S.

41. Why not? • Food safety inspections • Good sanitation • Medication widely available

42. Roundworms Dirofilaria is a roundworm that causes heartworm disease in dogs.

43. Ascaris: a parasitic roundworm Other Roundworms

44. Other Roundworms The roundworm is carried by mosquitoes in tropical Africa Elephantiasis results when a roundworm blocks the lymphatic system, causing severe swelling

45. Roundworms: Hookworms Hookworms attached to the intestines

46. Segmented Worms Earthworm leech

47. Segmented Worm Characteristics • Bilateral symmetry • Full Coelom (full range of motion, complex organs inside) • Complete digestion system • Most are hermaphrodites with sexual reproduction

48. Segmented Worm Characteristics • Gets O2 directly from moist skin, • closed circulatory system with hearts to deliver • Food – blood (leeches), or dirt (earthworms)

49. Earthworms Giant Earthworm Regular Earthworm

50. Earthworms • Swallow dirt, filter out food • Loosen soil, helps to aerate soil for plants • Also fertilizes plants with castings (poop)