BIO 340 - Chapter 4 (EXAM 1)
BIO 340 - Chapter 4 (EXAM 1) BIO 340
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This 7 page Class Notes was uploaded by Jenna Larson on Saturday October 8, 2016. The Class Notes belongs to BIO 340 at Central Michigan University taught by Dr. Andrew McNaught in Fall 2016. Since its upload, it has received 3 views. For similar materials see Ecology in Biology at Central Michigan University.
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Date Created: 10/08/16
INDIVIDUAL ORGANISM WEEK 4 NOTES (9/19/16 , 9/21/16 WEEK 5 NOTES ( 9/26/16) OBJECTIVES 1. Describe how individual encounters the environment. 2. Describe how individual responds to abiotic (physical and chemical) factors. Physiology: Response = survival, gr owth, reproduction, metabolism Behavior: Response = action, reaction 3. Predict distribution, abundance, or phenotype. 4. Examine environment as a selective force leading to adaptation. RANGE OF TOLERANCE – range of values over which an organism can surv ive Response (Survival or activity) Range (Low to High) • Specialist (steno-): narrow range of tolerance (Red Line) • Generalist (eury-): wide range of tolerance (Blue Line) MULTIPLE FACTORS - Several factors may combine to limit distributions A pH X B Temperature Liebig’s Law of the Minimum: The environmental factor for which the organism has the least tolerance will control the distribution of the species. COMPLICATING ISSUES – Limits of tolerance may change with life stage Acclimation: Alters range of tolerance Behavior: Tactics to avoid lethal environments Chapter 4: TEMPERATURE RELATIONS WEEK 5 NOTES (9/26) Sources (+) and sinks (-) of heat for an organism Bird: Metabolism (+), Sun (+), Sand (+or-), Air (+or-) Fish: Metabolism (+), Water (+ or -) Processes: Radiation (+), Metabolism (+), Conduction (+or-), Evaporation (-), Convection (+or-) Organism response to changing temperature OPTIMAL FASTER DESTROYED Enzyme Activity SLOW DENATURES 0 20 40 Temp. (ºC) Physiological Response: Enzyme systems High Temperatures – Inefficient enzymes, increased respiration costs , enzyme shut-down and deactivation Low Temperatures – Metabolic processes slow, ice crystal formation Acclimation – Short-term, physiological change with multiple enzyme forms Dormancy – Reduced metabolism; Low body temp. , used to adjust to extreme environments Torpor – Short-term reduction in metabolism Hibernation (too cold)/Aestivation (too hot) – Long-term reduction in metabolism Behavior: Avoiding extreme temperatures Animals: migration to a new area, find/make shelter, nocturnal (cooler at light) Plants: open and close stomas to reduce water loss, face the sun for photosynthesis Predict distribution Animals: Temperature influences survival , winter range/distribution (ex. eastern phoebe) Plants: Temperature (indirectly) influences availability of water, soil drought (temp. too high = water evaporation) , frost drought (temp. too low = frozen water) Predict phenotype Animals: body size increases with increasing latitude (Bergman’s Rule), larger individuals have a lower surface area to volume ratio, lose les s body heat as the body gets larger Example: Bears range from tropics (smallest) to polar bears (largest) Plants: Temperature influences growth form ( phenotype) Example: Yarrow (Achillea) grows on slopes of Sierra Nevada Mountains , large form at low elevation, small form at high elevation -Could they have differing genes/DNA/genotypes? -How can you tell the difference between phenotype and genotype variations? Temperature is a strong selective force. -Single species may have wide variety of shapes and sizes in different climates ( ex. Achillea) -Natural Selection acts on individuals, eventually populations evolve -Are short Yarrow plants a different genotype? (Clausen et al. 1948) -How would you test phenotype vs. genotype? Common garden: plant seeds from different phenotypes in the same environment Transplant experiment: Exchange small seeds and large seeds, switch environments Sequence genome CONCLUSION: Groveland (low) and Aspen Valley (mid) had phenotypic variations but no genetic variations – differences are due to phenotype Big Horn Lake (high) plants had genetic variations – differences are due to genotype Adaptations to hot and cold environments Plant Adaptations Warm environments : succulence, closed stomates, white/reflect light, thick cuticle, high convection, low conduction, small/reflective/parallel/no leaves, large surface area-to-volume ratio ex. Prickly pear cactus, yucca, tumbleweed Cold environments: grow close to ground/reduce exposure to wind, small/dark/ highly absorbent leaves, low convection, high conduction ex. Animal adaptations Warm environments : light pigmentation, little or no fur, find cold environments (caves/mud/water) ex. Iguana Cold environments: dark pigmentation, thick or bushy fur, burrow to retain heat, thermal neutral zone ex. Marmot Physiological Strategies to survive temperature changes Body temperature Homeothermic – temperature within the body remains fairly constant Poikilothermic – temperature within the body changes fairly often Source of heat energy Ectothermy – source of energy lies outside of the body/from the environment ex. reptiles, fish, plants, i nsects Endothermy – source of energy lies within the body/homeostasis ex. mammals, birds, large marine fish, some flying insects, thermogenic plants Countercurrent heat exchange – mechanisms allowing blood to flow to coldest part of extremity without heat loss Costs and Benefits Ectotherm: Endotherm Thermal Neutral Zone Chapter 4: WATER RELATIONS WEEK 5 NOTES (9/28) WEEK 6 NOTES (10/3) Where does organism gain or lose water? Plant Frog Shark Roots (+) Urine (-) Gills (+,-) Stomates (-) Skin (+,-) Food (+) Food (+) Skin (+,-) How does organism gain or lose water in bodily processes? Absorption (+), Secretion/Excretion (-), Evaporation (-), Transpiration (-), Osmosis (+,-), Ingestion (+) How does an organism respond to desiccation? Plants: need water for support and metabolic processes ; shuts stomates, lose leaves, reduce leaf size (Euphorbid) Terrestrial Animals: behavioral solutions; seek shelter, nocturnal activity, orient body away from the sun, face into the sun, capture water Predict organism distribution based on response to water stress Example: Predict leaf size from environmental tem perature and moisture • Many small leaves (sunny/dry) or few large leaves (shaded/moist)? • Model (Givnish and Vermeij 1976) • Water Use Efficiency ; Costs? Benefits? Photosynthesis ÷ Evaporation Photosynthesis: Increase size = increase boundary layer Increase size = increased surface temp. PS Increased temp = impact photosynthetic enzymes SMALL LARGE Leaf Size Evapotranspiration: Increase size = increase boundary layer Increase size = increase humidity Increase size = increase H20 gradient Increase size = increase evapotranspiration E SMALL Leaf Size LARGE Moist Environment Arid Environment PS or E optimal optimal Leaf Size Leaf Size Plant and Animal Adaptations to Extreme E nvironments Drought resistant plants (xerophytes) – deep roots, leaves (small, thick cuticle, white hairs), lose leaves to prevent evaporation, become succulent Aquatic plants – have air spaces (lacunae), develop floatation ability on top of water Terrestrial animals – water-proof exterior (insects, hydrocarbons), concentrate urine (loop of Henle in kidneys, longer loop=less urine), reclaim water vapor in breath, water storage ex. camel – fatty hump stores water, no sweat, very dense coat to protect from extreme heat ex. kangaroo rat – condenses water in nasal passages and “swallows” Aquatic Animals: maintain osmotic balan ce (not gaining or losing water) ex. marine bony fish (teleost) – Adaptations to avoid losing water by d rinking large volume of sea water, excrete salt (Cl , Na follows, Mg , SO 2+ 4 2) through gills ex. fresh water bony fish – Adaptations to avoid gain ing water, excrete large volumes of dilute urine, ingest salts with food/a bsorb salt (Cl , Na follows) through gills ex. anadromous fish – live for the majority of life in salt water, travels up a fresh water stream to breed; gill pumps switch from pu mping out to pumping in to maintain salt and water balance (ex. salmon, sea lamrey) (eels do the opposite and travel to the ocean to breed) END OF EXAM 1 MATERIAL EXAM 1: I – 40 multiple choice II – 24 definitions (compare/contrast) III – 36 long answer (~1 paragraph essay) Total = 100 points