Invertebrate Biology

1. Invertebrate Biology Chapter 33

2. Phylogentic Relationships of Animals Platyhelminthes Porifera Mollusca Chordata Arthropoda Annelida Cnideria Nematoda Echinodermata pseudocoelom segmentation acoelom Protostome: schizocoelem Deuterostomes: eucoelom radial symmetry bilateral symmetry no true tissues true tissue Ancestral Protist

3. Kingdom Animalia • Eukaryotic, multicellular organisms with cells organized into distinct tissues. • Heterotrophic nutrition • Most exhibit significant capacity for locomotion. • No cell walls; has a plasma membrane. • Includes sponges, sea anemones, snails, insects, sea stars, fish, reptiles, birds, and human beings.

4. Sponges Phylum Porifera Class Desmospongiae Class Calcarea Class Hexactinellida Class Sclerospongia

5. Phylum Porifera Characteristics • No true tissues or organs • No symmetry • No nerves, muscles, mouth or digestive system or • Sessile • Reproduce sexually and asexually • Skeletons composed of CaCO3 or SiO2 spicules or spongin • Filter feeders 5,000 species

6. Skeletal Structure • Consists of organized cells supported by a skeleton of: • spongin fibers • calcareous spicules • silica spicules • a combination of these, or perhaps no skeletal structure at all

7. No Gut SpongesPhylum Porifera

8. Predators • A few species of fish • seaslugs • hawks bill and loggerhead turtles • Can use toxins to ward off predators

9. Refuge • Sponges provide habitat for wide variety of animals. • As many as 16,000 different species of animals have been found in one loggerhead sponge.

10. Desmospongiae • Most marine sponges (>80%) • All freshwater sponges • Leuconoid • Spongin and SiO2 spicules

11. Calcarea • Contains all asconoid forms • Most syconoids • Generally small in stature • CaCO3 spicules

12. Hexactinellida • Mostly deep sea forms • Glass-like lattice work • SiO2 spicules

13. Sclerospongiae • CaCO3 foundation with SiO2 spicules • Found in Pacific and West Indies

14. Reproduction • Asexual: • production of external buds that detach or remain to form colonies • internal buds called gemmules that form during unfavorable periods • fragmentation (regeneration) • Sexual (mostly hermaphroditic): • eggs are retained in the mesohyl and fertilized by motile sperm that enter through the internal canals.  Zygotes develop into flagellated larvae,  which break loose and are carried away by water currents.

15. Phylum Cnidaria Class Hydrozoa Class Scyphozoa Class Cubozoa Class Anthozoa Hydra Portuguese Man-Of-War Stinging Limu Fire Coral True jellyfish Box jellies Sea wasps Corals Anemones

16. Phylum Cnidaria Stinging cells & 2 stages in life cycle Radial symmetry Tissues and organs Diploblastic Mouth and digestive cavity (blind sac gut) 9,000 species

17. Polyp Medusa mouth/anus gastrovascular cavity epidermis mesoglea gastrodermis gastrovascular cavity mouth/anus

18. The Cnidarian Life Cycle The Hydrozoan Life Cycle

19. Nematocysts

20. Class Hydrozoa “Stinging Limu”

21. Hydrozoan Medusa

22. Class Hydrozoa Close Up of a Portuguese Man-Of-War

23. Class Scyphozoa

24. Class Cubozoa Seawasp Box Jellies

25. Subclass Zoantharia Order Actinaria Sea Anemones Class Anthozoa

26. Subclass Hexacorallia Order Antipatheria Black Coral & Wire Coral Class Anthozoa Black coral Wire coral

27. Class Anthozoa “True” Stony Corals lobe finger mushroom Porites rus

28. Phylum Ctenophora • Diploblastic • 8 rows or combs of cillia • Colloblasts- adhesive structures • Hydrostatic skeleton • Blind sack gut

29. Phylum Platyhelminthes Class Trematoda Class Turbellaria Class Cestoda

30. Phylum Platyhelminthes Flatworms Blind digestive cavity Bilaterally symmetrical Thin, simple circulation Sensory organs at front Many parasitic 10,000 species

31. Pharynx Class Turbellaria Flatworm Anatomy Fig. 33-10 Gastrovascular cavity Mouth Eyespots Ganglia Ventral nerve cords

32. Hawaiian Flatworms Pseudoceros cf. rubroanus Pseudoceros ferrugineus Planocera cf. oligoglena Pseudoceros dimidiatus Pseudobiceros sp.

33. Life History of a Blood Fluke Class Trematoda

34. Class Cestoda

35. Phylum Nemertea • Bilaterally symmetrical and dorsoventrally flattened. • Body has more than two layers of cells with tissues and organs. • Body has a through gut with a mouth and anus. • Body has no body cavity. • Has a blood system with blood vessels. • Has a well developed nervous system and a brain. • Has an eversible and retractable ectodermal proboscis. • Reproduction is by asexual fragmentation, or sexual, when it is normally gonochoristic. • Most species are carnivorous and predatory. • Most are aquatic and marine, there are some terrestrial and freshwater forms.

36. Phylum Nemertea Ribbon worm

37. Phylum Rotifera • Bilaterally symmetrical. • Body has more than two cell layers, tissues and organs. • Body cavity is a pseudocoelom. • Body possesses a through gut with an anus. • Body covered in an external layer of chitin called a lorica. • Has a nervous system with a brain and paired nerves. • Has no circulatory or respiratory organs. • Reproduction mostly parthenogenetic, otherwise sexual and gonochoristic. • Feed on bacteria, and protista, or are parasitic. • All live in aquatic environments either free swimming or attached

38. Phylum Rotifera

39. Phylum Nematoda Roundworms Primitive body cavity Gut & Anus No circulatory system Nervous system Very successful- well adapted to every ecosystem Many are parasites 500,000? species

40. Phylum Nematoda

41. Phylum Mollusca Class Polyplacophora Class Gastropoda Class Bivalvia Class Cephalopoda chitons Snails nudibranchs Squid Octopus Cuttlefish Nautilus clams More than 500,000 known species

42. Phylum Mollusca Well developed circulatory system Nervous system with brain Some with good eyes

43. Body Plan • Three main parts: • Muscular foot- for movement • Visceral mass- contains most of the internal organs • Mantle cavity- houses gills

44. Generalized Mollusc Anatomy mantle visceral mass foot

45. Feeding Types • Grazers (radula- scraping tongue) • Filter feeding • Egg eaters • Active predation

46. Class Polyplacophora

47. Class Gastropoda Subclass Opisthobranchia Spanish Dancer (nudibranch) & egg mass

48. Class Gastropoda Subclass Prosobranchia Cone shell Opihi Cowery periwinkle Triton’s trumpet

49. Class Bivalvia

50. Class Cephalopoda Day octopus