Ecology-Test 1 study guide

Define dichotomy by presenting the environment as a dichotomy of biotic and abiotic? In this class you will frequently hear me tell you to be cautious when someone talks about dichotomies, why?
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Define natural selectionthe process by which organisms that inherit helpful traits tend to reproduce more successfully than othersDefine adaptation from an ecological view; be sure to incorporate fitness as improving.Random changes to an organism that just happens to benefit them, and as a result of the change, they are more fit.List the steps of the scientific method in order of use among these (response variables, design, hypothesis, assess data, do the experiment).1. Question 2. Hypothesis 3. Prediction 4. Experiment 5. DataWhat is a "control"? What is replication (how many replicates are necessary)?Replication = the action of copying something 25-30 is ideal, any more is better. Control - The group that is not experimented upon, either by giving a placebo or asked not to change; used to compare treatment group against; not told they aren't given anythingSelecting individuals for experimentation is critical, so defend your choice of a random choice of individuals versus a systematic sampling, and also comment on how you can control for individual age and gender. Is cost and labor an issue?Systematic sampling is a probability sampling method where researchers select members of the population at a regular interval. I picked this because there would be a lower risk of sample manipulation when it is all controlled. Yes, it is.What would you say is the most important part of the scientific method (admittedly an open ended and debatable question)?hypothesis/question was named in classDiscuss why our water from Lake Mead is high in calcium, high in pH, and the meaning of the phrase "hard water vs. soft water".The rock that makes Lake Mead is limestone and sandstone, and those are high in calcium. The white crust is calcium deposits after the water dries up, and it goes out of solution. The amount of minerals dissolved into water; hard water has a lot of dissolved metals and salts in it, soft does notUnderstand the basic chemistry of photosynthesis and respiration, and how they are kind of mirror images of each other.Respiration is the reverse of photosynthesis. You are consuming oxygen and sugar and producing water and CO2. Oxygen is the final electron acceptorWhy is there less oxygen available at greater water depths in lakes, oceans, and wetlands (distinguish between the limitations of light and role of microorganisms).Less light means less photosynthesis. Oxygen stays at the top layer of the water because it does not dissolve.On a broad level, what is the meaning of Figure 3.9?Marine animals were developed first as life evolved onto land. Therefore, there is more endemic species in the oceans than on land.Understand the temperature profile with season of a typical medium sized freshwater lake, and the ecological reasons for these patterns (Figure 3.38).Uniform temps found in spring and fall are due to the wind. The nutrients at the bottom of the lake get taken up and circulated.Give the definitions of epilimnion, metalimnion, and hypolimnion.Epilimnion: upper warm zone Metaliminion: Zone of change Hypolimnion: Deeper cool zoneCompare the two broad categories of freshwater lakes (oligotrophic vs. eutrophic) in terms of oxygen content, nutrient content, associated fish, and where does our Lake Mead fit in (this will depend on location)?Ogliotrophic: Good for fishing, high oxygen, low nutrients, trout. Eutrophic: Low oxygen, high nutrients, carp. Lake Mead is eutrophic.Define eutrophication using the paradox of the Las Vegas Bay (where the Las Vegas Wash enters L. Mead).Eutrophication of the wash causes algae growth, eventually dying, and the large abundance of dead algae increases bacteria and fungi (decomposers). They consume all of the oxygen in the water, so fish do not have enough, causing them to die.Which two factors are most responsible for the moderate climate variation at the Brazilian equator vs. the higher variation in the USA (think latitude and axis tilt)?1. Uneven heating of the earths surface 2. Tilt in the earths axisWhich factor can help us understand how precipitation and temperature varies in the mountain ranges of Nevada (think about how rainfall and temperature vary with elevation)?Mountain ranges obstruct precipitation causing it to rain over the mid-level elevations. With elevation, temp goes down and rainfall goes up so dry, cool air descends the mountain range.Trees pretty much suddenly appear as you approach ~5000 ft elevation locally, and trees tend to disappear entirely at elevations over ~10,000 ft. Explain the main factor involved in both tree lines.Rainfall predicts the tree line.The organic horizon of soils is deep in Iowa, but shallow in Nevada. Explain.We have less plant litter to make up this layer than Iowa does. (except fertile islands)Define biome and how temperature and precipitation combine to produce these communities (Fig. 2.1).Biome: the largest ecological community classification. Decreasing temp and increasing precipitation help explain the biomes.Characterize each of the 3 biomes considered in terms of soil quality, seasonality of climate, features of dominant plants that are present including those yielding relevant medical drugs, and relative humidity.Temperate forest: Fertile (lots of N) in soils with distinct seasons and dominated by deciduous trees (which are trees where the leaves fall and come back in the spring) Desert: Salty soils since it came from evaporated salt water. Fertile islands under shrubs as they drop leaves, and animals defecate under shrubs, plants have smaller leaves covered with hairs to help decrease temp and water loss. Precipitation highly unpredictable. Cactus. Tropical Rainforest: RH is 70%. High diversity with lots of medicinal plants bc of competition. Two seasons. Nutrients in biomass.How have humans affected natural communities (think in terms of assisting dispersal).We move many species around and let them loose.What is meant, regarding a trait, by "selected for" or "selected against"?when some individuals leave more offspring than others, the characteristics of these individuals are said to be "selected for". If all individuals survive, can selection occur?What is selected for in the figure on Slide 3? Slide 4?Cyanide resistance. Penicillin resistance.Explain how the tails of many lizards came to be detachable in terms of selection and fitness.Lizards selected to lose their tail due to predatory attacks. If the lizards develop a detachable tail, their fitness increases since they will survive an attack and be able to reproduce. Their offspring also gets the regenerative tail, and the trait continues to future generations.Define artificial selection and how this is widespread with our crops.Artificial selection is the same as natural selection except WE do it. WE spray generations of crops with pesticide to get them resistant to it. WE breed them.How does natural selection account for antibiotic resistance in bacteria? A cat washing her face?The organisms that unconsciously do these things do so unwillingly and because doing these actions resulted in a higher fitness.interpret Figure 4.20 on soybeans and johnsongrass, including the background of the study, design of the experiment, and outcomes.a. is this example of herbicide resistance fundamentally different from antibiotic resistance or pesticide resistance?Background on experiment: soybean fields invaded by weed: johnsongrass. Johnsongrass decreases soybean yield, it survives year to year through perennial rhizomes. Herbicide [glyphosphate = "roundup" , note cancer lawsuits] kills both soybeans and johnsongrass. Scientists genetically engineer genes for glyphosphate resistance in soybeans (GMO soybeans). Herbicide sprayed on fields of GMO soybeans only kills johnsongrass. In Argentina, soybean fields sprayed with herbicide for 7 generations. The ones exposed lived.What is/are the control treatments in Figure 4.20?No herbicideDefine and give an example of proximate and ultimate factors.Proximal factor is the cue, whereas the ultimate factor is the result that increases fitness (benefit/fitness result) An example could be mosquitos.Distinguish between nature and nurture (as recent evolution and acclimation) and understand the experimental design for Figure 4.4, including what a common garden is and what this kind of treatment tests for.Phenotype is a combination of nature and nurture. Nature determines the limits of a certain trait while nurture determines the exact value it will turn out to be. A common garden is a range of experimental designs in which organisms from different provenances are grown together under the same environmental conditions. Tests for acclimation or evolution.As in number (8) for the chuckwalla, figures on Slide19. What was the outcome and define what an ecotype is.The chuckwalla gets bigger as you go up the mountain; they're bigger because you get more rainfall which means more food for them. There is a correlation between rainfall and elevation. On the graph, the males and females show the same pattern; the trait is maintained when the environment is held constant, which tells us there must be genetic differences between the high elevation lizards, the middle elevation lizards, and the low elevation lizards; limited gene flow is a necessity to maintain this. These lizards are not exchanging varying genes. Evolution. Ecotype: An ecotype represents the same species with a different genotype.Discuss the relationship between gene flow and speciation, and how can you have evolution without speciation.In the absence of gene flow, you get speciation; gene flow interbreeding prevents speciation from occurring. If 2 populations are NOT exchanging genes, eventually they will be different speciesWhat does the Hardy-Weinberg principle state?In a stable population with no disturbing factors, the allele frequencies will remain constant from one generation to the next and there will be no evolutionDeviation from Hardy-Weinberg equilibrium (unchanging allele frequencies) often means that natural selection is occurring. However, what are other processes that may account for this?Mutation, migration, genetic drift, nonrandom matingBe able to recognize and explain examples of stabilizing, directional, and disruptive selection.Stabilizing = Graph moves to the middle Directional = Graph moves in one direction Disruptive = Graph moves in both directions away from the middleDiscuss the peccarie (javelina) example and Fig. 4.10 (the owl) given in class, including what is the selective agent, what is being selected for, and what kind of selection is shown.stabilizingUnderstand the butterfly larva experiment and indicate the data that support recent evolution, and the data that support acclimation.Acclimation is shown when comparing the same population at different temperatures, and recent evolution is shown when comparing different populations at different temperatures. Acclimation was shown when comparing Alaska 12C to Alaska 24C, and Michigan 12C to Michigan 24C. Recent evolution was shown when comparing Alaska 24C and Michigan 24C.How do the data presented on Figures 4.15 and 4.16 support the process of genetic drift?The figure is consistent with drift (2 mechanisms shown) because the results show two different populations compared to the original population with different genotype frequencies compared to the original population as well. The resulting population is also smaller than the original population.Explain the last figure in the lecture on the outcomes of selfed vs. outcrossed pollen.Inbreeding is bad.You are studying a local lizard and start by measuring the temperature of its environment. How would you consider microclimate vs. macroclimate in your measurements, which constitute part of the niche?Macroclimate is the temp Microclimate is influenced by altitude, vegetation, etc Niche is the habitatHow does microclimate vary, in the US West, by altitude, aspect, color, boulder effects, and burrows? See evidence presented in Slides 3 to 7.High soil tempsDiscuss the Principle of Allocation with reference to Figure 5.7 (E. coli at different temperatures), and touch on how the data relate to recent evolution and type of selection.Since the bacteria were more fit at 20C, they became less fit at 40C as they had to allocate resources to become better in their current environment of 20C. This is not reversible or short term - evidence of recent evolution. Directional selection has occurred (shifting to one side). This organism cannot simultaneously optimize growing at both 20 and 40.Distinguish between recent evolution and acclimation in Fig. 5.10 (use the one with standard error bars).South Carolina has good evidence of acclimation at all three temperatures. New Jersey has marginal evidence between 33C and 36C, but good evidence of acclimation at 30C vs 33C. Evidence of recent evolution between South Carolina and New Jersey is present at 33C as South Carolina is significantly better at MEI than New Jersey at the same temperature. There is no evidence of recent evolution at 30C and 36C.Give the experimental design for Fig. 5.12, and what the data mean.genetic differences were eliminated by collecting cuttings from the same individuals in Death Valley (Atriplex).Step 01, collect cuttings from Death Valley individuals.Step 02, grow these cuttings (clones) at warm (40C day) and cool (23C day) temperatures in greenhouse.Step 03, expose both sets (cool grown, warm grown) to a range of temperatures: this is what is graphed. AcclimationDefine ectotherm and endotherm, and how an ectothermic lizard can still regulate body temperature close to 33C (Figure 5.19).Ectotherm regulates body temp from outside sources Endotherm regulates its own temp Using its environmentDefine the thermal neutral zone of endothermic animals and what we can conclude from the data shown on Fig. 5.24. Address these:(a) the tropical vs. arctic dichotomy.(b) human origin implications.(c) possible weaknesses of this figure.An endotherms thermal neutral zone does not change. Human body temp is wrong.What is a countercurrent heat exchanger and where might you see such a system?Appendage(Dolphin flipper)What is unusual about the skunk cabbage metabolic rate as ambient temperature varies? (fig. 5.29, 5.30)a. what is the proximate factor for flowering of the skunk cabbage?metabolic rate only increases when the temp declinesDifferentiate between hibernation and torpor, and use the hummingbird behavior as an example of the latter.a. What would be a possible disadvantage of routine, nightly torpor for hummingbirds?b. Why might the frequency of torpor and hibernation be more common among animals in tropical dry forests compared to those living in tropical rain forests? [think in terms of available resources throughout the year in each area]torpor is a short state of lowered metabolic rate and thus lowered body T hibernation is a longer state of reduced metabolic rate that allows the individual to survive winter conditions when resources are in short supplyIn looking over Fig. 5.31, discuss selection in both morphology and behavior that allows this beetle to maintain a fairly constant body temperature even though it is an ectotherm?rests in shade during the day, has stilted legsDefine relative humidity (RH) and how RH is related to temperature (Figure 6.2).a measure of how much water vapor is in a water-air mixture compared to the maximum amount possible Directly relates to air tempDefine osmosis, isosmotic, hyperosmotic, and hypoosmotic (Figure 6.4).osmosis is the diffusion of water down a concentration gradient. isosmotic describes equal [solute]s between organism and its environment. hyperosmotic describes organisms with a higher [solute] than its environment. hypoosmotic describes organism with a lower [solute] than its environment.Which trait costs the animal the least amount of energy in order to osmoregulate (choose from isosmotic, hyperosmotic, hypoosmotic), and why.isosmoticUnderstand Figure 6.5 (discuss how water potential varies from pure water to dry air, and what is the critical water potential for most desert shrubs).water tends to move toward a more negative Ψ, with dry air having the most negative ΨHow do most animals lose water? take in water?intake is primarily by drinking and absorption. loss is primarily by evaporation, transpiration, and excretion.Understand Figure 6.10, including how food digestion can yield liquid metabolic water, allowing the kangaroo rate to survive without drinking.Lots of water is gained by eating foodWhile an animal can drink or oxidize food for water, what does a plant do to adjust (acclimate) to a water shortage? [see Figure 6.11].Can grow larger rootsIn Figure 6.13, why is the water potential (of leaves) of Digitaria higher than Eleusine?Eleusine has a lower root massGive a potential weakness of the data in Figure 6.14? and how the data in 6.15 offers a better comparison.6.15 did dry to wet which is a better comparison and they are of the same genusFor each of the following traits commonly observed in desert plants, comment on how water loss is affected by increasing: leaf area, leaf thickness, leaf surface to volume ratio, stomata number, stomata location, pubescence (hairs), and dormancy.The ocotillo seems to violate the trends in question (11) above. Explain.opportunism,short-term exposure to stress Because they are drought-deciduous,What is an evaporative cooler (=swamp cooler) and how does the cicada utilize the same principle to cool its body?constantly evaporates water off its bodyHow can we state that in terms of energy, a marine shark uses less energy than freshwater shrimp? (in your answer use hyperosmotic). This question relates to question (3) above.Sharks have an evolution towards isosmotic conditions which uses the least amount of energy.The mammalian and avian kidney (with a loop of Henle) has convergently evolved to efficiently osmoregulate. Explain how it works, including osmolarity, interstitial fluid, filtration, reabsorption, secretion, excretion, and osmosis in your answer (last slide).hyposmotic so water absorbs and filtrates at points