Diversity II Notes Week 6
Diversity II Notes Week 6 211
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This 10 page Class Notes was uploaded by Jacob Erle on Wednesday March 2, 2016. The Class Notes belongs to 211 at Syracuse University taught by Justine Weber in Spring 2016. Since its upload, it has received 50 views. For similar materials see Diversity of Life II in Foreign Language at Syracuse University.
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Date Created: 03/02/16
Diversity of Life Notes II Week 6 2/23/16 Non-Insect Invertebrates (Inverts) I Opisthokonts – includes true fungi, metazoan animals and close protist relatives -possess flat mitochondria cristae, fairly common -posterior flagellum during some part of life cycle Animals “metazoan” – eukaryotic, multicellular, lack cell wall but possess similar cell structures, true tissues, motile at some life stage, heterotrophic (some have photosynthetic symbionts) -most lineages appear anywhere from 541-670MYA (Cambrian Explosion) -most metazoans (animals) are inverts INSECTS rule the Animal World -over 50% of inverts are aquatic; arthropods have been very successful at invading land; many terrestrial inverts still need water during some life stage Focus on: -differences among (34) phyla, primarily marine and some freshwater -major traits of each (morphology, habitat, life cycle, examples, uses and impacts) -major groups/selected taxa Porifera (pore bearing, “sponges”) -“Collared flagellates” -multicellular -older (Precambrian) -free-living (aquatic); 98% are marine -motile or sessile -not recognized as animals until 1765 -trap bacteria and detritus - Origins/links to protists; genetic analysis shows link to early animal ancestors Choanoflagellate protists Body plan/Morphology -asymmetrical/superficially radial -covered in holes -lots of good fossil preservatives -no fixed shape -no true tissues -cells totipotent/regeneration; most cells can change form/function -water circulation -choanocytes – flagellated cells to circulate water through canal system -in ostia, filters material for eating, and out osculum -layers -outer (pinacoderm) – permeated with pores, can be coated with collagen -inner (choanoderm) – has choanocytes (collar cells) -middle layer is variable (‘central jelly’, gelatinous) -amoeboid cells can make skeleton if present -contractile cells can slowly move without nerves/muscles -will open and shut holes to avoid hazardous toxins, also helps to clean out passages -spicules – calcium carbonate or silicon dioxide with collagen fibers -at first sponges classified solely by morphology, but now is based more on genetic comparisons (often correlates with spicule type) -basic body plan -Asconoid – single layer, small holes -Synconoid – slightly more complex -Leuconoid – thick middle layer (larger surface area for materials to pass through) -more complex body plan means more nutrients obtained, but does require more energy -no longer thought plans are strictly related to phylogeny within this group Ex. Grantia, Scypha (synconoid, also have some leuconoid forms Habitat and Ecology -Aquatic, 98% marine -Sessile – attached to bottom, or some organisms Feeding – filter phytoplankton and dissolved organic material -filter own volume of H20 every 10-20s -some are predacious (hook prey using modified spines) Protection from predators – spicules just aren’t that tasty -also produce toxins Symbionts -algae, animals (live in sponges as hiding places) -parasites of mollusks, shrimp, fish -some live on coral reefs by ‘boring’ secrete chemicals to erode reef structure to secure a living spot Life Cycle and Reproduction -asexual – fragments -sexual – most are hermaphrodictic with egg and sperm produced at different times -Larvae are generally free swimming, can be retained to help settle elsewhere Gemmule dormant phase, especially in some freshwater species (Spongilla) -form of asexual reproduction, makes resistant propagules (common in freshwater species) Growth patterns & rates -some large and can be over 2m tall, others small clumps -grow by constantly adding new cells, encrust on various surfaces -some show rapid growth, others are much slower (100 year-old sponges) Examples -Spongilla (green in nature) – freshwater, relatively common in NYS; can have algal symbionts -Demospongiae -Cliona, boring oyster sponge of shellfish Various forms: tube, blue basket, barrel Class Hexactinellida (‘glass sponges’) – presented as wedding present in some cultures Class Calcarea (‘calcareous sponges’) Uses -commercial bath sponges -bioactive compounds (tumor inhibiting agents) Human Impact -overharvest -sedimentation Resistant to hydrocarbon, detergent and heavy metal pollution Cnidaria (‘stinging nettle’) >11,000 described species -includes jellyfish, sea anemones, corals Body plan/morphology -radial symmetry -cnida (stinging or adhesive structures) -nematocysts – injects venom into prey, often with barbs that embed in prey tissue -incomplete gastrovascular cavity – only body cavity -no cephalization (lacking a head) -have simple net of nerves, but no nervous system -no separation of gas exchange, excretion or circulation Tissue layers endoderm, ectoderm, and middle layer (mesoderm or mesoglea) Body Forms Polyp or Medusa (both have radial symmetry) Habitat and Ecology -exclusively aquatic -most are carnivorous, using cnidae for prey capture -nematocysts – capsules with toxins and/or spines to penetrate and paralyze prey -spirocysts – adhesive -digest prey in gastrodermus Symbiosis -dinoflagellates living in corals (provide nutrition) -some live attached to other organisms Defense -Tentacles seen in anemones used in defense, also for competing over food & space -can withdraw tentacles into defensive mode Life Cycle and Reproduction -asexual reproduction is common, many can form colonies -most have dimorphic life cycle – polyploid (hydroid) and medusoid forms -planular lavae – propelled by cilia -planktonic – dispersal stage if adults are sessile Examples Class Hydrozoa Portuguese man o’ war (will sting you even if it’s dead) Hydra Fire coral, Millepora (has potent stinging nematocysts) -life cycles can be polyp, medusa, or both - epidermal gonads -wide distribution, freshwater and marine -middle layer (mesoglea) is non-cellular Class Scyphozoa -‘true’ jellyfish; more active, mostly seen in open water -medusa stage predominates -middle layer does have cells Cassiopeia, upside-down jellyfish Aurelia, moon jelly (common in NY marine waters) Class Cubozoa - sea wasps and box jellies -Australian ‘sea wasp’, ‘cubozoans’ -fast and maneuverable -often square shape -very toxic sting -found in tropics/subtropics -many pneumatocysts -can cause cardiac arrest, temporary paralysis 2/25/16 Class Anthozoa – no medusa stage -includes sea fan (Gorgonian), anemones, corals (hard, brain, soft) Human Uses -aquarium trade, tourism, Hawaiian islanders use toxins to help stun fish they hunt (spear tips) Impact -harvest for food, aquaria, jewelry -Damaged by trawling, pollution – have devastating food web effects Seen in NY -marine, freshwater (invasives) -many good fossil specimens Bilateria -bilateral symmetry -3 germ layers: endoderm, mesoderm, ectoderm -extra middle form used in embryogenesis Protostome – first opening of embryo is MOUTH Vs. Deuterostomes – first opening of embryo becomes ANUS Platyhelminthes (flatworms) -skinnny, flat, nonsegmented -head has central nervous system with nerve cords extending throughout the body -Primitive protonephridia, analogous to kidneys – used for excretion/osmoregulation -many are hermaphrodites, parasites Class Turbellaria – 16% of all flatworms -blind gut -no respiratory, circulatory system, appendages or skeleton -oxygen diffuses across body surface -great regenerative powers -3 cell layers -ciliated epidermis with many glands rhabdites -excrete materials for locomotion, predatory deterrence -most are free-living (aquatic or on/in soil); some commensal, parasitic -polyclad turbellarians – marine mostly -predatory, some eat detritus Ex. Dugesia Class Trematoda – 18-20k species -parasitic flatworms “flukes” of verts and inverts -digenetic trematodes (2life stages – 2 hosts) -can live without oxygen (can live in internal areas) -capable of specialize on specific organs of hosts, feed on host tissues using mouth and digestive system -most are hermaphrodites Ex. Fasciola hepatica – sheep liver fluke (snails are intermediate hosts) Schistosomes – blood flukes -important parasites of animals, including humans (200million infected) leads to chronic liver disease, schistosomiasis -seen in areas of poor sanitation; avoid being in water systems contaminated with human feces -pair can live up to 10years and produces hundreds of eggs a day Swimmer’s itch – supposed to infect waterfowl caused by infected snail -can’t infect people, but burrowing into skin causes welts Class Cestoda – Tapeworms, over 3400 described species -infect humans from undercooked meat, endoparasites in intestines -covered with tegument specialized ciliated epidermis -lack mouth and digestive tract -3 body regions: head (scolex), neck, strobila (body) -not true segmentation, but form sequentially and appear to be similar to true segments (not separated by walls) -high repro capacity -in 1800s people would infect themselves with tapeworms to try to lose weight Rotifera (wheel bearer) over 1800species -bilaterally symmetrical -smallest metazoans (<1mm long) -have toes, adhesive glands -many are free-living -Corona – ciliary band for feeding and locomotion -aquatic, very abundant in freshwater systems (200-5000/L of water) -Lorica – hard case, protection against predators -Tropi (jaws) made of chitin, different shapes -Malleate (hammers) – used to mash material, algae eaters -Virgate – will suck food up or puncture prey and absorb contents -Forcipate – extend out and grab food Class Bdelloida (leech-like), ~200species -identified by jaws -only seen doing asexual reproduction, for over 40million years Class Monogonata (90% of species) -small (30micrometers to 1mm) -diverse morphology -some are sessile, but purely planktonic -some are individuals, others colonial Life Cycle -diploid (females) done via parthenogenesis (amictic) -mictic females produce haploid egg to produce male Life History -fast generation times -vivparous -most lay 1 egg at a time, carried for 1-3 days Nematoda, over 25000 described species but possibly 1million -most abundant multicellular animals on the planet -bilaterally symmertrical -unsegmented -complete gut -unique excretory system, but no special circulatory or gas exchange structures -males and females, only sexual reproduction -ubiquitous -look similar, but very different phylogenetics -few with intermediate hosts -bacterial feeders, fungal feeders (remember nematode-trapping fungus), predate other nematodes, parasites of arthropods Ex. C. elegans, Trichinella spiralis Whipworms and Hookworms seen in humans, canines Human uses -biocontrol of soil-dwelling insects Hygiene hypothesis – possibly used to treat inflammatory bowel disease -Also are parasites of plants – plant root feeders (root knots of carrots, tomatoes) Pinworm infects 11-12% of humans (more in younger children)