Midterm 2 Study guide
Midterm 2 Study guide ECOL 182R
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This 14 page Study Guide was uploaded by Camille Hizon on Thursday February 25, 2016. The Study Guide belongs to ECOL 182R at University of Arizona taught by Bonine, Hunter, Martinez in Spring 2016. Since its upload, it has received 521 views. For similar materials see Introductory Biology II in Science at University of Arizona.
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Date Created: 02/25/16
ECOL 182 EXAM 2 STUDY GUIDE Diversity of Animals 2: Protostomes (other than Arthropods) I. Cnidarians – hydras, jellies, sea anemones, corals a. Basic body form i. two basic body forms: polyp and medusa ii. a sedentary and mobile form b. key adaptations i. Nematocysts: stinging threads that function like miniature harpoons. Used for: 1. capturing prey 2. defense against predators 3. defending territories 4. Corals secrete calcium carbonate c. feeding niches i. carnivores that use their tentacles to capture small animals and protists and to push the prey into their mouths ii. corals: shallow, clear, nutrient-poor water d. reproduction i. asexual reproduction – budding off from polyps II. Lophotrochozoa (the Platyhelminthes) a. basic body form i. grow incrementally by adding to their skeletal elements ii. Platyhelminthes – no coelom iii. in most, mouth but no anus iv. lack circulatory, respiratory system, absorb O2 through body wall v. slow movement vi. bilaterally symmetrical, incomplete digestive tract (a gastrovascular cavity) b. feeding niches i. some free-living; many parasites ii. Ex: Schistosoma – cause disease called Schistosomiasis c. reproduction i. some asexual ii. sexual, most hermaphrodites – two hermaphrodites lie next to each other, each donates sperm to the other’s egg III. Annelida – segmented worms a. basic body form i. head with brain – more sophisticated nervous system ii. coelom iii. segmentation of body and coelom iv. respiration across body wall b. feeding niches i. feeding varied ii. Earthworms eat organic material in soil ECOL 182 EXAM 2 STUDY GUIDE iii. Marine polychaete worms are filter feeders/parasites/predators iv. leech – blood c. reproduction i. usually sexual reproduction IV. Mollusca a. key adaptations i. bright colors – sign of toxicity ii. defend themselves with nematocysts iii. mantle – sheet of skin 1. secretes shell, forms gills for gas exchange, and in cephalopods forms muscular cavity that forcibly ejects water for locomotion iv. radula – hardened tongue b. feeding niches i. mostly grazers (ex: snails on algae) ii. or predators (cephalopods) c. reproduction – sexual V. Nematoda a. feeding niches i. many free living decomposers and parasites of almost everything b. reproduction i. sexual – some species have both sexes, some are hermaphrodites VI. Definitions a. Nematocyst – specialized cnidae that are characteristic of jellies and other cnidarians. it is an explosive cell containing one giant secretory organelle; used for prey capture and defense from predators b. Chromatophores – pigment-containing and light-reflecting cells, or groups of cells, found in a wide range of amphibians, fish, reptiles, crustaceans, and cephalopods. c. Medusa- one of two types of cnidarian body forms; an umbrella-like body form; also called a jellyfish d. Polyp – one of two types of cnidarian body forms; a columnar, hydra-like body e. Plankton – a diverse group of organisms that live in the water column of large bodies of water and cannot swim against a current. They provide a crucial source of food to many large aquatic organisms, such as fish and whales. f. Radula – used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon which is typically used for scaring or cutting food before the food enters the esophagus. g. Nudibranchs – brightly colored a marine gastropod mollusk that sheds its shell after the larval stage. Uses nematocysts as defense mechanism. h. Cephalopods – a member of a group of mollusks that includes squids and octopuses. i. Schistosoma and Schistosomiasis – see above ECOL 182 EXAM 2 STUDY GUIDE j. Trichinella and trichinosis – a round worm parasite of mammals including rodents, pigs, and humans; pigs get infected by eating uncooked meat k. intermediate host – a host that harbors the parasite only for a short transition period, during which (usually) some developmental stage is completed l. definitive host – a host in which the parasite reaches maturity and, if possible, reproduces sexually m. medicinal leeches – bloodletting popular for centuries; fell out of favor in mid 1800s VII. Practice Questions: a. The fully lined cavity between your outer body wall and your digestive tract is an example of a i. coelom Diversity of Animals 3: Arthropods and Deuterostomes I. 4 Subphyla a. Chelicerata b. Crustacea – dominant marine arthropods c. Myriapoda d. Hexapoda II. Why are there limits to arthropod size? III. Why have insects been so evolutionary successful? i. the ability to fly has been a major factor in their success IV. Key morphological characters of Echinodermata, Chordata? a. Echinodermata i. Ex: sea stars, sand dollars, and sea urchins ii. lack body segments, most are radially symmetrical as adults iii. not closely related to cnidarians or other animals that never show bilateral symmetry iv. have endoskeleton – a hard internal skeleton v. have a water vascular system b. Chordata i. Dorsal, hollow nerve cord ii. notochord – a flexible, supportive, longitudinal rod located between the digestive tract and the nerve cord iii. pharyngeal slits - gill structures in the pharynx, the region of the digestive tub e just behind the mouth iv. a muscular, post-anal tail (a tail posterior to the anus) V. Distinguish lineages of vertebrates a. Three linages of fishes i. Jawless fishes ii. Cartilaginous fishes – have a flexible skeleton made of cartilage. ECOL 182 EXAM 2 STUDY GUIDE iii. Ray-fin fishes- most bony fishes, including tuna, bass, perch, and the rainbow trout are ray-finned fishes. Their fins are supported by thin, flexible skeletal rays. b. Terrestrial vertebrates i. amphibians ii. reptiles (including birds) and mammals VI. What habitat would you expect to see amphibians in? a. Can be on land or in water but are most likely in water because their eggs would dry out in land. VII. 3 types of mammals: a. Monotremes – the egg-laying mammals. i. Ex: duck-billed platypus. b. Marsupials – have a brief gestation and give birth to tiny, embryonic offspring that complete development while attached to the mother’s nipples. The nursing young are usually housed in an external pouch, called a marsupium. i. Kangaroo and her joey c. Eutherian mammals – commonly called placentals because their placentas provide more intimate and long-lasting association between the mother and her developing young than do marsupial placentas. Make up about 95% of the 4500 species of living mammals. VIII. Definitions a. Pentaradial symmetry – only exhibited by phylum Echinodermata; ex: sea stars, sea urchins, sea lilies, sand dollars, and sea cucumbers b. osmoregulation – the active regulation of the osmotic pressure of an organism’s body; meaning fluids maintain the homeostasis of the organism’s water content c. estuary – a partly enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. d. Complete metamorphosis – larval stages are specialized for eating and growing and look very different from the adults, which are specialized for dispersal and reproduction. Metamorphosis from the larval stage to the adult occurs during a pupal stage. i. Ex: caterpillars, which are larvae of moths and butterflies e. notochord – a flexible, supportive, longitudinal rod located between the digestive tract and the nerve cord; found in animals in phylum Chordata f. Swim bladder – a gas-filled sac; evolved from balloon-like lungs, which the ancestral bony fishes may have used to supplement their gas exchange by gills in shallow water. g. dorsal hollow nerve cord – present in chordates; dorsal means “back” side, as opposed to front of an organism; IX. Practice Questions a. Contrast the skeleton of an echinoderm with that of an arthropod. i. an echinoderm has an endoskeleton, an arthropod has an exoskeleton b. Most of Earth’s species of living organisms are… ECOL 182 EXAM 2 STUDY GUIDE i. insects c. The phylum Arthropoda is named for its members’ i. jointed appendages Bacterial Symbionts of Animals I. Symbiosis a. Intimate association between unrelated organisms b. Includes parasitic (harmful), mutualistic (beneficial) relationships, and ones that are difficult to categorize c. A symbiont is a smaller organism that lives in or on the larger one. d. Microbial symbionts are everywhere (not just in animals), and not just bacteria e. Not all bacteria are germs; skin bacteria protect against infection II. Why are we only learning this now? a. Less than 1% of bacteria can be cultured b. Many bacteria look similar, even when using electron microscopes c. We have a limited ability to investigate complex communities of bacteria with just morphology. III. Review a. Polymerase chain reaction (PCR) - makes lots of DNA out of a very small amount. i. Short segments of DNA (primers) bind to genes of interest at each end. Then: heating and cooling, a DNA polymerase, and free nucleotides, causes exponential increase in number of copies. 1. What’s the value of making lots of DNA out of a very small amount? a. makes it easier to study ii. DNA sequencing - new techniques relatively inexpensive, makes sequencing a single bacterial gene from thousands of cells affordable. 1. What advantage does DNA sequencing have in helping us characterize the diversity of bacteria? 2. Critical technique that changed our ability to understand the mammalian gut flora (the bacteria in the gut) iii. The axenic (NO gut microbes) and gnotobiotic (reduced and known number of microbial species) mouse models. 1. Why do you think this might have been an important breakthrough? a. You can start looking at responses to individual components to give you an idea of what these things do and how they function iv. A critical effort to characterize all of the bacteria associated with humans: The Human Microbiome Project 1. Sequenced a single bacterial ribosomal gene IV. Bacteria ON animals a. Human Skin Bacteria i. Found about 1000 species of bacteria, a trillion cells, most non-pathogenic ECOL 182 EXAM 2 STUDY GUIDE ii. Amazing variation in the communities, e.g. compare “manubrium” (high chest) with front and forearm - completely different bacteria iii. What do they do? 1. Bacteria and sweat cause acid environment that makes it more difficult for pathogenic bacteria to establish 2. May secrete antimicrobial substances that keep pathogenic bacteria from dominating 3. A common theme: pathogens common in/on healthy individuals, not just causing disease 4. Ex: Bacteria on beewolves a. Capture bees; nest in sandy soil, put paralyzed bee in burrow - larvae feed on bees. When larval beewolves complete development, they spin cocoon, overwinter. Nest is moist: risk of bacterial or fungal infection b. Beewolves carry bacteria on their antennae i. Actinobacteria ii. Transmitted from mother to offspring iii. secreted in burrow by mother, incorporated into cocoon by larvae iv. each species of beewolf has its own species of bacterium v. Bacteria live in pockets in antenna, fed by wasp secretions c. What do you think the bacterium role is? How would you test this idea? i. You’re more likely to have successful offspring if you ii. remove actinobacteria so that bacteria can grow and potentially kill of larvae V. Bacteria in animal cells a. Not just in bacteria but lots of viruses, some protists are parasitic symbionts ( = pathogens) of human cells b. Bacterial cell pathogens are less dangerous now than they were - why? c. The bacterium Rickettsia prowazekii is carried by human lice, and causes typhus. d. Typhus i. very high fever, potentially leading to death ii. epidemics often followed wars and natural disasters where lice density was high iii. During WWI typhus caused 3 million deaths iv. thousands of inmates in Nazi concentration died of typhus v. Can be effectively treated with antibiotics. ECOL 182 EXAM 2 STUDY GUIDE e. They are vertically transmitted (parent-offspring), not horizontally or contagiously, like a cold, or most diseases we can think of i. Can we guess anything about the relationship between insect and bacteria from knowing how the bacteria are transmitted? f. Many of these interactions are beneficial for both partners (mutualism) i. Aphids - plant sap sucking insects - live on a diet that’s mostly sugar water with low levels of amino acids many not the kind they need to make proteins ii. They house bacteria in special organ - bacteria synthesize essential amino acids iii. Aphids without bacteria cannot reproduce iv. Aphids and bacteria have evolved together VI. Bacteria in guts a. In “mice and men” i. Historical (and quite recent) characterization of gut bacteria as “commensal” (i.e. beneficial to bacteria) b. In humans i. What’s in there? ii. About 1000 species, 100 trill cells iii. we may carry more bacterial cells than human cells iv. about 2-5 pounds of our weight c. Where do they come from? i. Birth canal - a few species ii. Mother’s milk - 600 species; in first few years, more and more bacteria are acquired d. In humans, what do they do? i. Make vitamins, digest complex starches ii. Help the gut develop normally iii. Help the immune system develop normally iv. Keep pathogens from making us sick. v. Many more claims, including roles in autism, reducing stress, etc. e. Communities of bacteria differ: i. an environmental component (some similarity within a household) ii. genetic component (identical twins bacteria more similar than fraternal twins) iii. Differences in bacterial communities between obese and thin people iv. Obese people have more bacteria from the phylum Firmicutes, fewer Bacteroidetes v. Thin people had the reverse, and a more diverse set vi. Obese people who became thin acquired a ‘thin person’s bacterial community’ vii. Nutrition differs depending on what bacteria one has viii. Ex: study performed in Malawi in 317 pairs of twins 1. Of the pairs of twins: a. 43% ECOL 182 EXAM 2 STUDY GUIDE b. In cases where twin differed, the gut flora (= community of gut bacteria) also differed 2. Does this show the gut flora is responsible? ix. Critical experiment - mice with gut flora from malnourished children lacked the ability to make some vitamins and digest complex carbohydrates. x. Ex: when Jason and Jonah compete in this Twinkie eating contest...They may eat the same number of Twinkies but get different numbers of calories from hem f. Questions i. What is the role of bacteria in determining obesity ii. What kind of data are the kinds we’ve heard about so far? g. Correlative data may not differentiate between cause and effect. i. Does the gut flora in an obese person CAUSE obesity? (causal explanation)? Or does obesity (the different physiological state of an obese person) AFFECT the type of bacteria that thrive in an obese person? ii. What kind of experiment would you like to do? 1. one that has a control, manipulated variable, etc iii. Study: 1. Collected microbes from guts of human twins, in each case one lean, one obese 2. Inserted collection of microbes from each twin into axenic mice 3. First result: mice that received flor from obese twin gained weight, ones that received lean twin flora didn’t even though ate similar amounts 4. Then wondered - what if mice are in the same environment? 5. The ‘lean’ bacteria did not transfer or prevent weight gain when mice were fed a high fat, low fiber diet (e.g. pelleted pizza and sweet breakfast cereal). But did when the diet was low in saturated fat, high in fruits and vegetables. iv. So should you get a thin roommate to stay thin? 1. May need a thin housemate who also eats well. v. What can we conclude from this study? 1. Does the study suggest a direct role of the gut flora on tendency to gain weight? 2. What role might diet play? 3. How much can we extrapolate from mice to people? h. Role of gut bacteria in development i. the gut lining (epithelium) does not develop correctly in axenic mice ii. among other things, the bacteria influence the number of microvilli, and the intestine's capacity to absorb nutrients iii. Early exposure to microbes may be necessary for calibrating the immune response to microbes ECOL 182 EXAM 2 STUDY GUIDE iv. Desired immune response - activate for pathogens, not against oneself or harmless bacteria v. Axenic mice produce abnormally high numbers of killer T cells - caused inflammation vi. As adults, more likely to have asthma and inflammatory bowel disease vii. The woman who almost died: 1. Likely contracted a pathogenic bacterial infection, Clostridium difficile, in hospital stay Clostridium infections linked with overuse of certain antibiotics, 3 million people infected in US/year. 2. Had ongoing diarrhea, cramps, and vomiting for a year - antibiotic treatment didn’t help (and helps only 15-25% of patients generally) a. Why might they not have worked? i. developed resistance 3. Eventually got a fecal transplant from her husband - tube went down her nose, past the stomach and into the small intestine 4. Cured within 24 hours 5. Feces: about 50% bacteria 6. was initially the cure of last resort viii. Recent clinical trial 1. patients with C. difficile infections 2. 16 received bowel lavage + fecal transplant, 13 received bowel lavage + antibiotics, and 13 received antibiotics alone Animal Form, Function, and Physiology I. Introduction A. Animal structure is fundamentally related to function B. Animals are generally studied through their anatomy and physiology 1. Anatomy - the study of an organism’s physical structure 2. Physiology - the study of how the physical structures in an organism function C. Both are diverse! II. Anatomy A. Definition: Physical structure (aka form) of an organism/and or its components III. Physiology A. refers to “nature, origin”, “knowledge” B. Definition: study of the mechanical, physical, and biochemical functions of living organisms. IV. Tissues, Organs, and Systems A. If a structure found in an animal is adaptive 1. The structure’s size, shape, or composition will correlate w/ its function 2. Ex: beak size and shape in ground finches on the Galapagos Islands B. If a mutant allele alters the size and shape of a structure to make function more efficient ECOL 182 EXAM 2 STUDY GUIDE 1. Individuals with that allele produce more offspring 2. Allele will increase in frequency over time V. Structure and Function at Cellular and Molecular Levels A. Correlations between form and function begin at the molecular level 1. Ex: protein shape correlates with protein role as enzymes, structural components of the cell, or transporters B. Similar function between structure and function occur at the cellular level 1. Ex: cells that secrete digestive enzymes contain a lot of rough ER and Golgi bodies C. Likewise, cell shape and function correlate 1. Absorptive cells have a large surface area. VI. Tissues are Groups of Cells that Function as a Unit A. Animals are multicellular - their bodies contain distinct types of cells that are specialized for different functions. B. A tissue is a group of similar cells that function as a unit 1. Embryonic tissues give rise to four adult tissue types a) Connective b) Nervous c) Muscle d) Epithelial C. Connective Tissue 1. Consists of cells loosely arranged in a liquid, jellylike, or solid matrix. 2. Matrix comprises extracellular fibers and other materials 3. Is secreted by the connective tissue cells themselves 4. The nature of the matrix determines the nature of the connective tissue 5. Loose connective tissue - contains an array of fibrous proteins in a soft matrix a) Examples include adipose and fat tissue 6. Dense connective tissue - found in the tendons and ligaments; connects muscles, bones, and organs 7. Supporting connective tissue - has a firm extracellular matrix; includes bone and cartilage 8. Fluid connective tissue - cells surrounded by a liquid extracellular matrix a) Ex: blood contains various cell types and has a specialized extracellular matrix called plasma D. Nervous Tissue 1. Nervous tissue consists of nerve cells, or neurons, and several types of supporting cells 2. Most neurons have two distinct types of projections from the cell body, where the nucleus is located a) Short, branching dendrites, which transfer electrical signals from other cells to the cell body ECOL 182 EXAM 2 STUDY GUIDE b) Long axons, which carry electrical signals from the cell body to other cells E. Muscle Tissue 1. A key innovation in the evolution of animals - like nervous tissue, it appears in no other lineage a) Functions in movement 2. Three types: a) Skeletal muscle b) Cardiac muscle c) smooth muscle F. Epithelial Tissue 1. Epithelial tissues (epithelia) are tissues that cover the outside of the body, line the surfaces of organs, and form glands 2. An organ is a structure that serves a specialized function and consists of several tissues. 3. A gland is a group of cells that secrete specific molecules or solutions 4. Epithelia carry out several functions a) Protection b) Transport of water and nutrients 5. Epithelial cells typically form layers of closely packed cells 6. All epithelial tissue has a polarity a) The apical side faces away from other tissues b) The basolateral side faces the animal’s interior (1) The basal lamina connects the epithelial to the connective tissue c) The apical and basolateral sides of an epithelium have distinct structures and functions G. Functions of Apical and Basolateral Epithelia 1. The apical side of an epithelium generally lines organs and secretes mucus. a) An example of this is the lining of the esophagus b) Cells are actively undergoing mitosis 2. Basolateral side links the apical to the basal lamina H. Organs and Organ Systems 1. Cells with similar functions are organized into tissues 2. tissues are organized into structures called organs 3. organs are part of organ systems which consist of groups of tissues and organs that work together to perform one or more functions I. Form, Function, and Adaptation 1. Biologists who study animal anatomy and physiology are studying adaptations 2. Heritable traits allow individuals to survive and reproduce in a certain environment better than individuals that lack those traits ECOL 182 EXAM 2 STUDY GUIDE 3. Adaptation results from evolution by natural selection VII. The Role of Fitness Trade-Offs A. Trade Offs - inescapable compromises between traits 1. Ex: quality and quantity of offspring B. Researchers investigated the predicted trade-off between egg size and egg number (clutch size) by manipulating these parameters in crickets 1. mating in crickets involves a behavioral adaptation 2. their results showed that such trade-offs do exist VIII. Adaptation and Acclimation A. Adaptation is a genetic change that occurs over generations in response to natural selection in a population B. Acclimatization, or acclimation 1. A phenotypic change that occurs in an individual 2. In response to a short-term change in environmental conditions 3. Acclimation often is applied to change that take place in the laboratory setting C. Allometry 1. Which animal was bigger in real life? 2. Isometry (1:1) is rare D. What are effects of changing body size among species? How does SA/V ratio change as we consider larger and larger species? 1. How do things change with body size? a) Allometry E. Surface Area/Volume Relationships: Theory 1. The cell surface area determines the rate at which gases and nutrients diffuse across the membrane 2. The cell volume determines the rate of diffusion a) As a cell gets larger, its volume increases much faster than its surface area does b) The physiological activity can be measured as the metabolic rate 3. Volume increases faster than surface area as animals become longer (bigger) 4. Metabolic rate - the rate at which oxygen and energy are consumed a) Often measured as oxygen consumption per unit time b) The consumption of energy is measured as the basal metabolic rate (BMR) c) BMR is the rate at which an animal consumes oxygen while at rest with an empty stomach, under normal temperature and moisture conditions d) The BMR is measured in mL of O co2sumed per gram of body mass per hour F. Comparing Mice and Elephants 1. Small animals have higher BMRs than do large animals ECOL 182 EXAM 2 STUDY GUIDE a) Ex: an elephant has more mass than a mouse, but a gram of elephant tissue consumes much less energy than a gram of mouse tissue does 2. As an organism’s size increases, its mass-specific metabolic rate must decrease a) Or the surface area available for exchange of materials would fail to keep up with the metabolic demands of the organism 3. Per-gram metabolic rate is LOWER if animal is larger. IX. How Do Animals Regulate Body Temperature? A. Heat exchange is critical in animal physiology 1. overheating can cause proteins to denature 2. protein denature can lead to dehydration 3. low body temperatures can slow down enzyme function and energy production B. Mechanisms of Heat Exchange 1. All animals exchange heat with their environment in four ways: a) Conduction (solid-solid) b) Convection (solid-liquid/gas) c) Radiation (no direct contact) d) Evaporation (phase change) C. Variation in Thermoregulation 1. There is also a continuum regarding whether animals hold their body temperature constant 2. Homeotherms keep their body temperature constant 3. Heterotherms can tolerate changes in body temp 4. Many animals lie somewhere in between these two extremes D. Chemical and biological reactions tend to happen faster at higher temperatures. E. Q10 effect; how much does metabolic rate change with 10C change in temperature? 1. Q10 typically between 2 and 3 X. Variation in Thermoregulation A. Many animals can control their body temperature through process of thermoregulation, including 1. obtaining heat 2. holding body temperature constant B. An endotherm produces adequate heat to warm its own tissue C. an ecotherm relies on heat gained from the environment D. humans are endothermic homeotherms XI. How do endotherms and ectotherms differ with respect to metabolic rate? A. Higher for endotherms because they rely on their own energy reserves for thermoregulation. ECOL 182 EXAM 2 STUDY GUIDE
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