Dr. Christine Palmier Biology 120 Lab

Transcription

1 Dr. Christine Palmier Biology 120 Lab

2 Animals Invertebrates Vertebrates (More abundant) (Less Abundant) Evolution and Development of Bilateral symmetry Appearance of a head (cephalization) Digestive system True coelum(body cavity) Segmentation

3 Sponges (Porifera) P. Porifera = sponges most primitive did not give rise to other animals asymmetrical, some radial symmetry sessile (immobile) adults, free-swimming larvae 2 cell layers 1) outer = epidermal 2) inner = flagellated collar cells (bring water and food inside thru osculum filter-feeding) skeleton composed of spicules(calcium carbonate and spongin) and secreted by amoeba-like cells

4 Sponges (Porifera)

5 P. Cnidaria P. Cnidaria = corals, hydra, sea anemones, jelly fish radial symmetry (advancement vs. some sponges) 2 body forms a) sedentary polyp (hydra) b) motile medusa (jelly fish) Sac-like gut, one opening (no anus) 2 cell layers a) epidermis b) gastrodermis, jelly to separate layers and allow buoyancy for floating of medusa Stinging nematocysts to capture prey/food and defense

6 Hydra,Jelly Fish, Sea anemones Coral, (Cnidaria)

7 Hydra,Jelly Fish, Sea anemones Coral, (Cnidaria)

8 1) Hydrozoans marine and colonial Polyp is predominant (sessile, immobile) Use polyps for feeding, sting prey and for reproduction 2) Jellyfish true polyp form is reduced or absent horse-shoe shaped gonads 3) Corals and sea anemones Only polyp form is present Stinging tentacles to capture drifting food secrete calcium carbonate coral reefs Sea anemones do not have calcium carbonate contain symbiotic algae

9 Jelly fish medusand polyp

10 Coral and Sea Anemone

11 P. Platyhelminthes P. Platyhelminthes flat worms Still only one opening for digestive system (no anus) Advances include 1) more specialized tisses 2) several, well-developed organ systems 3) bilateral symmetry (first time) head development/cephalization localization of sense organs

12 P. Platyhelminthes flat worms

13 Free Living Parasitic Planaria feed on small animals or scavenge (dead, organic matter) cilia for movement flukes parasitic; in liver, lungs, bladder, or blood vessels of vertebrates suckers for attachment to host monoecious/hermaphroditic or dioecious primary host for adult fluke = vertebrate intermediate host for larvae = usually a snail tapeworms specialized parasites for life in intestine (pre-digested food) attach to host by scolex(suckers & hooks) proglottids follow scolex formed by budding, reproductive unit (1000s/1 proglottid) leave host thru feces new hosts (muscle of cattle & pigs) poorly cooked human intestine

14 Planaria

15 Flukes

16 tapeworm

17 P. Nematoda P. Nematoda Most widespread of organisms complete digestive system (mouth and anus) False body cavity present (filled w/ reproductive organs) no protective lining around organs, but some separation of organs Some parasites of plants and animals

18 Nematodes (round worms) Ascaris

19 Vinegar eel

20 Trichnia

21 Today s Lab Look at: Models and diagrams of sponges prepared slide of spicules bath sponge vs. basket sponge specimens of Cnidariaand identify radial symmetry, tentacles, mouth, sac-like cut, polyp, medusa Portuguese man-of-war (Cnidaria, hydrozoan) specimens and pictures Obelia(Cnidaria, hydrozoan) life cycle, demo slides of colony and medusa For hydrozoa, draw reproductive polyp, feeding polyp, and medusa Moon jelly life cycle, tentacles, medusa, 4 oral arms, gonads Coral development of coral reefs, specimens, pictures Sea anemones pictures and preserved specimen hydra feed them, cause discharge of nematocysts, slide or picture of nematocyst, model