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Animal Diversity I. BIOB 171. Background. Domain Eukarya , Kingdom Animalia Heterotrophic – obtain food by ingesting other organisms or their by-products Lack cell walls Pass through a blastula stage Arose approx. 620 - 550 mya 35 major groups (we will look at 9). Parazoa.
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Animal Diversity I BIOB 171
Background • Domain Eukarya, Kingdom Animalia • Heterotrophic – obtain food by ingesting other organisms or their by-products • Lack cell walls • Pass through a blastula stage • Arose approx. 620 - 550 mya • 35 major groups (we will look at 9)
Parazoa Rotifera??
Eumetazoa • All multicellular animals • Organisms in this group have either radial or bilateral symmetry
Two developmental trajectories in Eumetazoa: That’s us!
Hydras aren’t any of these…. Super simple design with 2 layers Rotifers are pseudocoelomate
Protostomes • Two large groups: • Lophotrochozoa – The name is based on the trochophore larva found in within this group. Includes annelids, molluscs, flatworms, and maybe rotifers • Ecdysozoa – Animals in this group undergo molting (ecdysis) or the shedding of an outer body cover. Includes roundworms, nematodes, arthropods (like insects, and more).
Today… We will be looking at these organisms… • Hydra (Cnidaria) • Rotifers (Rotifera) Why? Because the lecture needs to catch up to the lab!
Basic Characteristics Pages 181 – 183 • Read through and understand all 13 characteristics • As you perform the dissections and look at organisms today, refer to these characteristics. • Observe the animal and record your observations in the summary table on PAGE 224
Phylum Cnidaria – Hydras (Hydra) • Two tissue types, no complex organs • Includes: corals, jellies, sea anemones, and Portuguese men-of-war. • Most species are marine, few freshwater spp. • Two body forms present in the life cycle: • Umbrella-like, free-swimming stage • Cylindrical, attached or stationary form – often grows into colonies of individuals • Observe live hydra in a depression slide and try to feed Daphnia or liver juice with string • Also observe prepared slides
Phylum Rotifera- Rotifers • NOT IN LAB MANUAL • Very small animals – most 0.1 – 0.5 mm in length • Most common in freshwater, though some salt water species • Important part of freshwater zooplankton, being a major food source and many species contributing to decomposition of organic matter. • Pharynx contains tiny, calcified, jaw-like structure called trophi
Last minute thoughts… • Be sure to record your observations in the Table on page 224 (might be better to reproduce in your lab notebook). • If you have questions about your papers, please ask. Turn in your rough drafts (if you want feedback) by Friday.