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Invertebrates

Invertebrates. http://www.docstoc.com/docs/79739092/Invertebrates-Section-1. Metazoans. Metazoans. “Animals” Multi-cellular Develop from embryos Divided into two groups based on the presence of a backbone. Invertebrate Grouping.

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Invertebrates

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  1. Invertebrates http://www.docstoc.com/docs/79739092/Invertebrates-Section-1

  2. Metazoans Metazoans • “Animals” • Multi-cellular • Develop from embryos • Divided into two groups based on the presence of a backbone

  3. Invertebrate Grouping • Over a million described species 95% lack a vertebrate (or backbone) • This is an artificial grouping • No common lineage in evolution • No characteristics all inverts possess • Animal kingdom believed to have evolved in the oceans during the Archeozoic

  4. Age of Man Age of Mammals Age of Reptiles • Age of Fishes Age of Inverts http://hotelcondesdeharo.com/contacto/time-periods-dinosaurs

  5. Evolutionary Significance • Body Plans • Multicellular life, all major organ systems, complete digestice tracts, closed circulatory systems all evolve in an invert first • Pioneered the inhabitance of all parts of the planet

  6. Form and function in invertebrates Feeding and Digestion Intracellular digestion- the simplest animals use this, with materials being broken down inside the cytoplasm of cells

  7. 2. Extracellular digestion- Food is broken down outside the cells in a digestive cavity and then absorbed into the body cavity.

  8. Respiration Respiratory organs have large surface areas that are in contact with the air or water. Also, for diffusion to occur the respiratory surfaces must be moist. serc.si.edu w3.shorecrest.org daviddarling.info

  9. Circulation Blood is moved using one or more hearts and either an open or closed circulatory system. Open circulatory- blood is only partially contained within a system of blood vessels. Closed circulatory- blood is enclosed and circulated through vessels within the body.

  10. tutorvista.com

  11. Response Cephalization- where if any sense organs the animal has are located at the front of the head. Specialization- cells with particular jobs. • Example- chemosensory, compound eyes

  12. gizmag.com http://www.youtube.com/watch?v=tATaUFShLjc&feature=youtu.be

  13. Movement and Support Invertebrates have one of three main kinds of skeletal systems: hydrostatic skeleton, exoskeleton, or endoskeleton. thedragonflywoman.com hermanypk.blogspot.com http://webcache.googleusercontent.com/search?q=cache:yUxFNb3ebXUJ:www.whrhs.org/cms/lib07/NJ01001319/Centricity/Domain/221/EOC_answers.doc+biology+eoc+review+packet+whrhs&cd=5&hl=en&ct=clnk&gl=us

  14. Hydrostatic skeleton- muscles are surrounded by a fluid filled body cavity (worms, jellies) Exoskeleton- External skeleton- (molluscs and arthropods) Endoskeleton- A structural support located inside the body. (sponges and echinoderms)

  15. Sexual and Asexual Reproduction Most invertebrates reproduce sexually during at least part of their life cycle. Depending on environmental conditions, many invertebrates may also reproduce asexually.

  16. Invertebrate Groups

  17. Shapes: Tiny cups, broad branches, tall vases, encrusting round masses

  18. PORIFERA-sponges • Most primitive multi-cellular organisms • No symmetry • Aggregate of independent cells, lack tissues and organs • Sessile and filter feeding • 10,000 species and three classes based on type of spicule

  19. Fig. 7.7

  20. Cnidaria • First animals to move-primitive nervous system and muscle tissue • First animals to have a space for digestion • Radial symmetry and stinging tentacles • 4 classes: Anthazoa, Hydrazoa, Scyphazoa, • Two body types: polyp and medusa

  21. Pleurobrachia Beroe

  22. Ctenophora • Probably an offshoot of Cnidaria, similar body plan • Biradial symmetry • Ciliary combs and sticky tentacles for catching prey • Known for bioluminescence

  23. Worms on • Bilateral symmetry in all the rest of the invert groups from this point on… • Worms are first groups to develop complete digestive tract, blood vessels, body cavity, headlike area, and a coelom • Most are soft bodied, live in tubes and deposit feed or suspension feed.

  24. Flatworms • Most primitive bilateral animal • Acoelomate- no body cavity /solid body • Trematoda and cestoda classes are parasitic • Turbellaria are carnivorous, many have eyes • Incomplete digestive tract

  25. Nemerteans • Offshoot of flatworm groups • Acoelomate- no body cavity /solid body • Simple circulatory system with blood vessels • Complete digestive tract • Proboscis for catching food- may be poisonous and barbed • Entirely carnivorous and prey on annelid worms and small inverts

  26. Nematodes • Pseudocoelomate- not a true body cavity but a similar fluid filled space • Complete digestive tract • Some of most widespread and numerous multicellular animals • 1 m2 of mud can have up to 4,420,000 in it • Covered by scales or cuticle • Free-living and parasitic species

  27. Leech Sabella pavonina Nereis sp. Lumbicus terrestris

  28. Annelids • Segmented worms- important in increased mobility and evolution of appendages • Largest worms and most differentiated • Coelom • Head-like area • Polychaetes-parapodia on each segment, some with poisonous bristles, gills, eyes and sensory organs on head • Many feeding methods • Hirudinea-leeches: parasitic

  29. Mollusca • Second largest invert phylum and fossils back to the Cambrian era • Diversity of form based on an ancestral body plan: bilateral symmetry, head with tentacles, muscular foot for locomotion, shell-excreted by mantle tissue, radula for feeding, open circulatory system in most and coelom • Gastropoda, Bivalvia, Cephalopoda

  30. Arthropoda • 80% of all known species • Chitinous exoskeleton-molted for growth • Jointed appendages but tendency towards reduction in number and more specialized in use • Small coelom, open circulatory system, high degree of cephalization, well-developed sense organs and behaviors • Subphylum chelicerata and crustacea

  31. en.wikipedia.org en.wikipedia.org

  32. Chelicerata • Body lacks antennae, divided into cephalothorax and opisthoma • 5 to 6 pairs of walking arms and book gills • Chelicerae –feeding appendage • Merostomata- horseshoe crabs • scavengers and feed on molluscs, worms and bottom dwelling algae • Pycnogonida-sea spiders • Also have proboscis for feeding • Exclusively bottom dwelling

  33. Mollusc-Annelid Connection • Similar embryology • Similar segmentation in a group of molluscs called monoplacophores • Molecular evidence Arthropod-Annelid Connection • Similar segmentation • Similar appendaginglike polychaets • Embryology • Similar organ system arrangement

  34. Crustacea • 2 pairs of antennae, mandibles, maxillae, and compound eyes • Areas of body are specialized by region and in some cases fused together • Biramous appendages • Great range of diet and even some parasitic examples

  35. Echinoderms • Only major invert group that is a deuterostome. • Entirely marine and largely bottom dwelling • 5 part radial symmetry but start life as bilateral larvae • Endoskeleton of calcium carbonate • Water vascular system for locomotion and attachment

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