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Practice Questions TAXONOMY 1. What is the order of classification from BROADEST to MOST SPECIFIC? Life – Domain – Kingdom – Phylum – Class – Order – Family – Genus -­‐ Species 2. What are the 3 Domains of life? What characteristics sort organisms into these domains? Bacteria, Archaea, and Eukarya are the 3 Domains. Organisms are sorted into these kingdoms based on cell type (prokaryotic v. eukaryotic), cell number (multicellular, unicellular, or both), and method of obtaining nutrients (autotrophs v. heterotroph). Bacteria: Prokaryotic, Unicellular, Heterotroph, Autotroph (photosynthesis) Archaea: Prokaryotic, Unicellular, Autotroph (chemosynthesis) Eukarya: Eukaryotic, Unicellular, Multicellular, Heterotroph, Autotroph (photosynthesis) 3. What are the 4 Kingdoms in the Domain Eukarya? What are the characteristics of these kingdoms? Animals: heterotrophic, multicellular, and found in diverse environments Plants: autotrophic (photosynthesis), multicellular, and found mostly on land Fungi: heterotrophic, MOST OFTEN multicellular, decomposers Protista: can be both autotrophic (photosynthesis) and heterotrophic, can be multicellular OR unicellular, and this is the catch-­‐all kingdom 4. What makes up a scientific name? What are the rules to writing a scientific name correctly? A scientific name is a 2-­‐part name, usually in Latin or Greek, that describes one particular species. It is made up of the genus and species names; the genus name comes first and is followed by the species name. The rules to writing the scientific name correctly are: (1) capitalize the Genus name, but lowercase the species name; (2) write in italics or underline 5. What does this sentence mean: “As you go from a BROAD classification level down to a MORE SPECIFIC classification level, the number of species decreases at each level, but the number of characteristics that the species have in common increases at each level.” At the broadest levels of classification, organisms are sorted into groups based on general similarities. There is a large number of organisms in each group at this level, because the groups are based on broad similarities (cell type, presence of a spine, etc.) As they move through the more specific levels of classification, the number of traits that they have in common with organisms that share the classification level increase. The number of organisms at each level, however, decreases. This is because these organisms have different characteristics and are sorted into other, more specific groups. In order to share several levels of classification, organisms must have many traits in common. INVERTEBRATE VIDEO 1. Why can sea stars and crabs regrow their limbs, but we cannot? Sea stars are much simpler organisms than we are. If we had to regrow an arm, we would have to regrow bone, muscle, connective tissue, blood vessels, nerves, skin cells, hair cells, and nail cells. We’d also have to regrow an upper arm, elbow joint, fore arm, wrist joint, hands and fingers. Super complicated! Sea stars are very simple and it does not require nearly as much energy to regrow a limb. 2. Why do we only see big invertebrates in the ocean? Without a backbone, it is hard to support yourself. When a big invertebrate (like an octopus or a jellyfish) is on land, it cannot do anything, it just flops over. When it is in the water, the water supports it and it is able to swim quickly and gracefully. Large invertebrates would not have enough internal structural support on land; they need the additional support of the water. 3. What does the nervous system of MOST invertebrates look like? Most invertebrates have a very simple nervous system. The nerves are spread throughout the body and invertebrates have instinctual, simple reactions (Grab that thing! Eat that thing! Move to the thing!). Cnidarians have a nerve net, which disperses nerve cells around its body. Echinoderms have nerve rings that help guide movement and eating. 4. What is the exception to the “invertebrate-­‐no-­‐brain” rule? Cephalopods have highly sophisticated brains. Octopus and cuttlefish have especially well formed, complex nervous systems that produce complicated behavior like camouflage and problem solving. 5. What is the invertebrate reproductive strategy? Most invertebrates use external fertilization and produce a lot of tiny offspring. External fertilization is where males release sperm into the water and females release eggs into the water. Fertilization of the egg happens in the water, outside of the invertebrates’ bodies. Invertebrates produce hundreds – thousands of very small offspring that have to change and develop into adult forms. Most of the offspring do not survive, but because so many offspring are produced in one round of reproduction, even a 10% survivorship produces enough new organisms to keep the population going. MARINE INVERTEBRATES 1. What structures do all mollusks have in common? Mantle, foot, some sort of shell (internal or external), and all have soft, squish bodies 2. Make a list of all of the organisms based on their body symmetry. Radial: Cnidarians 5-­‐Part: Echinoderms Bilateral: ALL MOLLUSKS: Cephalopods, Bivalves, Gastropods, and Arthropods: Crustaceans No Symmetry: Porifera 3. Describe the difference between suspension and filter feeders. Suspension feeders reach out into the water column to grab food particles when they pass close by and bring the food to their mouths. Filter feeders pull water into their bodies, strain out the food, and then release the extra water and waste. 4. What do all echinoderms have in common? Spiny skin, tube feet, water vascular system. 5. What adaptations do crustaceans have? Exoskeleton (protection, prevents water loss), Jointed appendages (increased mobility), Specialized appendages (able to get food more easily, able to move more easily, sense environment better), segmented body (allows for specialization of body parts and more sophisticated organisms). 6. What are the types of Cnidarians? Which are polyps and which are medusas? How do you know? Jellyfish (medusa – mouth faces down, tentacles face down, free swimming), Coral (polyp – sessile, mouth faces up, tentacles face up), Anemone (polyp – sessile, mouth faces up, tentacles face up) 7. Describe filter feeding in sponges OR bivalves. Sponges: Collar cells beat flagella to create a current and the sponges pull water in through pores in their sides. Food is filtered out by the sponge, water is released through the top opening (Osculum). Bivalves: water is pulled into the bivalve through the incurrent siphon and passes over the gills. Food is trapped in the sticky mucus on the gills and moves into the mouth. Water passes out of the animal through the excurrent siphon. 8. Describe suspension feeding in cnidarians. Cnidarians have nematocysts (stinging cells) on their tentacles. When prey comes into contact with the tentacle, it triggers the nematocyst to fire. The nematocyst injects venom into the prey, paralyzing it, and then the cnidarian pulls the prey into its mouth with its tentacles. 9. What do all cnidarians have in common? Nematocysts, tentacles, radial symmetry, nerve net, mouth, stomach, and muscles. 10. What is the purpose of “sensory tube feet” in echinoderms? Echinoderms do not have eyes, only eye spots, so they need a way to navigate. The Sensory Tube Feet allow the echinoderm to sense chemicals in the water and follow the trail to food, away from danger, or to other echinoderms to mate. 11. How do bivalves bury themselves? They use their muscular foot to pull themselves into the sediment. Their siphons remain at the top – giving them access to food and oxygen – while they are safely buried in the sediment. 12. How do nematocysts work? Nematocysts fire when their trigger is touched. The barb shoots out of the nematocyst (wicked fast!!) and cuts into the flesh of the prey. The thread unfolds into the prey’s blood stream and delivers the venom. 13. Describe the nervous system of a cephalopod. How is it different from other invertebrates? Cephalopods have a sophisticated nervous system with a big brain. They use their nervous system to change their skin texture and color quickly to help them camouflage. Also, their complex brain helps them be very dexterous with their tentacles. Most other invertebrates have a very simple nervous system (nerve net) without a complex brain. 14. Define these names: Echinoderm, Gastropod, Porifera, Cnidaria, Cephalopod, Bivalve, Arthropoda, Echinoderm: spiny skin Gastropod: stomach foot Cnidaria: stinging nettle Cephalopod: head foot Bivalve: 2 shells Porifera: pore bearer Arthropoda: jointed appendages 15. If you were to happen upon a creature on the beach, what characteristics would you look for to tell you that it was an Arthropod? How would you know whether it was a Crustacean? I would know that the organism was an arthropod if it had the following characteristics: jointed appendages, body segments, and an exoskeleton. I would know that it was a crustacean if it had 2 – 3 body segments, at least 5 pairs of legs, and 2 sets of antennae.