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1. Although we are going to discuss �science as a way of knowing� (i.e., the scientific method) later in the first third of the course, describe in terms that a non-scientist could understand what the authors mean by the statement that �uncertainty is an inherent feature of science� (p. 9).
a. The uncertainty of science is that we can only look at small bits of nature at a time. It is very limited. There are tons of question and even more reasons and data to explain those questions. There area lot of factors that can play a old in the determination of the whys. Then conditions are limits, there are so many variables that effect every aspect of science.
2. In the text box Ecological Issues � The Human Factor (p. 13), the authors discuss topics similar to those of Diane Ackerman�s article referenced below. Answer the two questions on p. 13.
- a. How would you define nature? Does your definition include the human species? Why?
- i. Nature is defined as everything not mad made, but including humans. The things humans make are a distortion of natural things, thusly not natural
- b. What would you consider the most important environmental issue of your time? What roe might the science of ecology (as you know it) play in helping understand this issue?
- i. Overpopulation. The harm, the abundance of humans cause to this earth. Deforestation, pollution etc. It can answer many questions and can explain why species are found in new locations and why some species are lost.
3. Although not specifically discussed in the text, you probably know that most science is reductionist. Explain what this means. Based on the description of the science of ecology provided in this chapter, do you think that ecology is reductionistic or more holistic? Explain.
- a. Reductionistis is breakdown into parts. An approach to understanding the nature of complex things but reducing them into the interactions of their parts or to simpler or more fundamental things.
- b. Holism � properties of a given system cannot be determined or explained by its component parts alone, instead the system as a whole determines in an important way of how the parts behave
- c. I think ecology is more holistic. Every though it is looking at the interactions between individual organisms and their environments it studies a broad topic from organism and biosphere as individuals as a whole.
4. Describe the interactions involving wolves, cows, deer and plants described in this essay.
a. The wolves control the populations of deer and cows. The deer control by the wolf�s are not ravishing the plants. The cows become over abundant due to the killing of the wolves. The plants are destroyed by the deer because the would population was destroyed.
5. Leopold expresses the simple idea (on page 138) that �fewer wolves meant more deer�. Using information presented in this essay and your responses to Questions # 3 and #4 above, discuss why this simple idea is typically wrong.
a. Simply because they are talking about 1 specific place where the population of deer is uncontrolled sue to the killing of the wolves. But the population of wolves is not directly related to an abundance or lack of deer.. This is one specific event.
6. In the previous essay, the decision to extirpate a species was based on (albeit misinformed) ecological knowledge. Explain. In this essay, what was the basis of the decision to eliminate a species?
a. The was based on uninformed knowledge because this specific instance could not be known how one species of animals controls another. This was one specific event. In escudilla the basis was this bear being the thing that ate the cows. It was a cow county so they wanted the cows to come and thrive. So the bear was killed. Then the cows became over populated.
7. For Ackerman, what does �nature� include?
a. Nature included the full sum of creating and absolutely everything.
8. Do you agree or disagree with Ackerman�s claim that we, the species known as Homo sapiens, are also a part of �nature�? What is the basis of your answer to this question? In other words, state the reasons you �believe� one way or the other.
a. I believe we humans are apart of nature. I believe this because we affect the environment just like a plant, or any type of organism. We are made of cells, so are pants.
9. Identify which of the reasons you stated above are �scientific� and which are based on some other �body of knowledge� or �way of knowing�.
a. All being made of cells � scientific.
10. What gives rise to the yearly seasons on Earth? In other words, why is it winter right now in the United States and summer right now in Argentina?
a. The earths tilt. During summer solstice in the N hemisphere solar rays fall directly on the tropic of cancer (23.5 d N latitude). Days are longest in the N hemisphere and the sun heats the surface most intensely. Thus the S hemisphere (Argentina) experiences winter at this time.
11. On a much larger timescale (relative to the above question), what is thought to produce glacial advances and retreats? What were some of the effects of these glacial movements (during the last 18,000 years) on the ecology of organisms in Michigan (see Section 18.9 of the text)?
- a. Variability of the earths climate systems, operates on a timescale ranging from decades 10 of thousands of years. Driven by changes in the input of energy to the earths surface. The earths orbit is not permanent. Changes occur in the tilt of the axis and shape the path about the sun. These variations effect climate by altering the seasonal inputs of solar radiation.
- i. Occurring on a time scale of 10 of thousands of years the are associated with glacial advances and retreats thought out earths history.
- b. Michigan � Plant species and animals filed into the area where the glaciers used to be and distributed about. Distribution and avoiding of species subsequent structure of Forrest communities have changed dramatically.. 4 diff species of trees
12. What is a microclimate? What four physical attributes of the environment influence the transfer of heat in a microclimate? How do vegetation and topography influence microclimates?
- a. A microclimate is a climate on a very local scale which differs from the general climate of the area. Influences the presence and distribution of organisms.
- b. 4 attributes
- i. Light
- ii. Heat
- iii. Moisture
- iv. Air movement
- c. Vegetation:
- i. Moderate microclimates especially areas near the ground. Alter soil temp, moisture , wind movement, and evaporation. Influences both temp and humidity
- d. Topography
- i. Aspect (direction a slop faces) influence s local climate conditions
- 1. Northern hemisphere: south facing slopes receive the most solar energy.
- 2. North facing slopes recall the leas energies vary between theses extremes
- a. Different exposure to solar radiation sat south and north facing sites has a marked effect on amounts of moisture and heat present
- 3. Microclimates conditions range from warm, dry, variable conditions on the south
- e. North facing slope = cool, moist and more uniform condition.
13. For living things in general, why is water such an important abiotic environmental attribute?
a. Life processes take place in water, we are mostly made of water, plants need water, common, increased heat capacity, water changes tem slowly, thermal expansion, viscous, dissolving power (polar), absorbs or looses great quantities of heat to change temp, less dense when frozen, buoyancy
14. Even though some visible wavelengths of light can penetrate to more than 100 meters in the clearest aquatic environments, what fraction of visible light is absorbed by just 1 meter of water? How much does this absorption reduce the available solar energy?
- a. 1 meter of water is 40% of short waver radiation.
- b. Water absorbs wavelengths then others, visible red and infrared. In wavelengths > 750 reduces solar energy by half
15. True/False: In a typical lake in Michigan, the coldest water is always found near the bottom of the lake. Briefly explain your answer.
a. True. The water is colder and denser in the �hypolimnion�. The density changes at the thermocline (region of vertical depth profile when temp declines most rapidly) acts as a physical barrier that prevents mixing of upper (epilimnion) and lower (hypoimnion). As colder water becomes more dense and falls it pushed the warmer water up and it begins to cool. Surface water absorbs solar radiation which warms it up and the wind and surface waves distributes heat vertically.
16. As discussed in lecture, low pH can directly affect organisms by influencing physiological processes. Low pH, however, can also affect organisms indirectly. Briefly explain.
a. The concentration of toxic metals Aluminum dissolves as pH decreases and become more concentrated in aquatic environments. Organisms are unable to tolerate low pH conditions because acidic water increases the concentration of Al which is extremely toxic and leads to genera decline in aquatic populations
17. Relative to aquatic environments, the text discusses three constraints imposed by terrestrial environments on living things. Identify these constraints.
- a. Desiccation � loss of water
- b. Gravitational forces
- c. High degree of variability � tie & space/
- d. Temperature land (arid) increases then in water
- e. Timing and quality of precipitation
18. Describe how very cold temperatures and very warm temperatures can have the same effect on water availability in terrestrial environments.
a. Its constricted in both environments. Hot = evaporation. Cold = frozen
19. Although soil is difficult to define, the text lists four reasons why soil is important for terrestrial organisms. Identify these four reasons.
- a. Medium for plant growth
- b. Controls the fate of water in terrestrial environment
- c. Breaks down water product of plant and animals and then transforms then into their basic elements
- d. Acts as a habitat to diversity of animal life
20. Without using a lot of technical jargon, describe why some inorganic macronutrients are easily leached from typical soils while other inorganic macronutrients are usually retained by typical soils.
- a. Ability of macromolecule binding to the soil particles depend on the overall charge of the soil.
- b. Smaller macronutrients are more positive and held tight to the soil
- c. As h+ is added to the soil, it becomes increasingly acidic and some of the macromolecules are let go
21. When environmental temperature exceeds body temperature and it is necessary for an animal to lower its body temperature, which of the four mechanisms of �heat transfer� (discussed in lecture) are most important? When environmental temperature is less than body temperature and it is necessary for an animal to lower its body temperature, which mechanisms of �heat transfer� are most important?
1. What is rubisco and what does it do?
Rubisco is an enzyme (ribulose biphosphate carboxylase-oxygenase or RuBP). It catalyzes carboxylation.
2. Define/Describe light compensation point and light saturation point.
- light compensation point (LCP) is the point at which the rate of net photosynthesis is zero
- light saturation point is the point above which no further increase in photosynthesis occurs
3. Draw a hypothetical tolerance curve for an extremely shade-adapted plant that exhibits photoinhibition.
Photoinhibition is the negative effect of high light levels
4. On a sunny day in mid-summer, leaf temperatures may become high enough to inhibit photosynthesis. Which of the four mechanisms of heat transfer (discussed in lecture) would be most important in lowering leaf temperatures?
convection and evaporation
5. Figure 6.9 shows the photosynthetic responses of shade-adapted and sun-adapted plants. Describe these different phenotypic responses. What aspect of plant physiology determines (at least in part) these differences?
- ? Differences in the performance of sun versus shade plants are related to rubisco
- � Rubisco is a costly molecule for a plant to manufacture
- ? Shade plants produce less rubisco which reduces energy cost and leaf respiration rate and produces more chlorophyll
- � Lowers photosynthesis rate � Lower light compensation point
- � Restricts maximum photosynthetic rate because there is only so much rubisco available to fix CO2
6. Lab Exercise 02 explored the phenomenon of morphological phenotypic plasticity in plants. Is what you discovered consistent with the description of shade-leaves and sun-leaves given in the text?
I discovered that the shade leafs are bigger and weigh more then opposed to the sun plants. The sun plants had a smaller mass and SA. In the text is says the sun leaves are smaller and thicker then the shade.
7. ALL plants use the Calvin Cycle to incorporate CO2 into simple sugars. C3 plants (typical plants) obtain their CO2 directly from the atmosphere but not without a cost. Explain this trade-off, which was discussed in lecture.
- What do C4 plants and CAM plants do differently (in general) and why do they do it? Where do these species typically live? Why don�t all species use the C4 or CAM photosynthetic process? In other words, what is the cost of doing C4 or CAM photosynthesis?
- C3 plants are not very efficient, rubico also can act to produce CO2 which is release.. which is center productive because that�s what they need to make sugar.
- C4 plants have different leaf anatomy, they have mesophyll cells and bundle sheath cells. They divide synthesis between the two types of cells. So the bundle sheath cells counteract the loss of CO2 from the mesophyll. C4 plants live in warmer, dryer environments. C4 plants have a higher energy expenditure
8. Use Figure 6.20 to determine the minimum, maximum and optimum temperatures for Neuropogon and Atriplex.
- Neuropogon � Min = -3, Max = 20, Optimum = 6
- Atriplex � min = 15, Max = 40, Optimum = 30
9. Figures 6.22 and 6.23 demonstrate what physiological phenomenon? Explain.
These plants are able to adapt to the changing temperature to have an optimum temperature associated with a changing temperature.
10. For the typical life-form on Earth, (i.e., the majority of animals, plants and microorganisms), what is the minimum & maximum value for organismal (= body) temperature? What determines this range of tolerance? (NOTE: These questions are not about genetics; they are about how the physical environment constrains life.)
The body temperature is dependant on enzymes, too low and they will not function, too high they will denature and cause death.
11. How do some species of plants tolerate temperatures below 0 oC? What is the cost of this adaptation? Which trees in our part of the world typically possess this adaptation and which trees do not?
- Plants native to seasonally cold environments have evolved several adaptations for survival
- Frost hardening�the conversion of cold-sensitive cells into hardy ones
- Formation/addition of protective compounds�antifreeze
- Winter deciduous
12. Why is N (nitrogen) such an important nutrient for plants?
Nitrogen plays a major role in photosynthesis as it is the major element found in both rubisco and chlorophyll. The maximum (light saturated) rate of photosynthesis is correlated with the leaf nitrogen content
13. Answer STUDY QUESTION 13 on p. 125.
- How could increased leaf longevity (longer-lived leaves) function as an adaption to low-nutrient environments?
- Absorb more sunlight to produce more atp through photosynthesis to compensate for the lack of nutrients available
- Or, gather more stuff over a longer period to compensate for what can't be accumulated in a normal period
- a low rate of photosynthesis a leaf needs longer time to "pay back" the cost of production
1. With regard to acquiring sufficient amounts of C (carbon) and N (nitrogen), contrast the problems faced by typical herbivores and typical carnivores.
- Herbivores� diets are rich in carbohydrates and low in protein. Ration of C to N in plants is 50 to 1, and 10 to 1 in animals. Herbivores depend on bacteria to digest cellulose and proteins. The protozoa synthesize fatty acids, AA, proteins and vitamins.
- Carnivores problems is not obtaining enough food.
2. Briefly describe (in mostly non-technical terms) how ruminant and non-ruminant mammal herbivores solve the problem identified in the previous question.
a. They have many stomachs and lots of digestive enzymes making it capable to digest cellulose.
3. What is a mineral lick and who uses it?
a. A mineral lick is a place where there is nutrient rich soil for animals to eat. Ruminants
4. What is a homeostatic plateau? Give a specific example of this phenomenon with regard to core body temperature regulation in humans.
a. Organisms have limited range of tolerances or homeostatic plateaus. A negative feedback mechanism.
5. Describe homeothermy and poikilothermy. a) Do poikilotherms possess a thermal neutral zone like homeotherms? Explain. b) Distinguish between the possible phenotypic responses of homoeothermic animals and poikilothermic animals to fluctuating environmental temperatures. c) What is heterothermy?
- a. In endothermy, animals generate heat metabolically, and this results in the maintenance of a fairly constant internal temperature independent of external temperatures (homeothermy)
- i. Birds, mammals.
- b. In ectothermy, animals acquire heat primarily from the external environment (poikilothermy)
- i. Fish, amphibians, reptiles, insects, and other invertebrates
- c. The thermoneutral zone is a range of environmental temperatures within which the metabolic rates are minimal. The temperature range over which some organisms can maintain their temperature without appreciably changing their metabolic rate. Animals with body temperatures that fluctuate with the temperature of the immediate environment.
- d. No, they do not possess a thermal neutral zone.
- e. Homoeothermic animals would tend to have layers of fat, fur etc, while poikilkthermic animals would keep a smaller body type to be able to be warmed by the environment.
- f. Heterotherms are animals that regulate body temperature by both endothermy and ectothermy
- i. Bats, bees, and hummingbirds
6. Discuss the role of factor interaction with regard to the thermoregulatory abilities of Bullfrogs and Green Frogs.
a. They exert considerable control over their body temp. They bask in the sun and can raise their body temp up to 10deg C above ambient temp.
7. Briefly describe the constraint that size imposes on ectotherms and endotherms.
- a. An animal�s size (SA/V ) influences whether or not it may regulate body temperature
- b. Body size is constrained to a level where the entire body can be warmed by the environment
- c. Large poikilotherms (e.g., alligators) are restricted to warmer environments
- d. The smaller the organisms (larger SA/V ), the greater the relative heat loss to the surrounding environment
- e. This heat loss must be offset by increased metabolic activity
a. In figure 7.16 why does mass-specific metabolic rate (metabolic rate per unit weight) of mammals increase with decreasing body mass?
i.The smaller the organisms (larger SA/V ), the greater the relative heat loss to the surrounding environment
b.Why do homeotherms typically have a greater amount of body insulation than do poikilotherms?
- i. Homeotherms regulate exchange between the body and environment by insulation
- ii. Fur: barrier to heat flow, insulation value varies with thickness
- iii. Fur thickness changes with the seasons
- iv. Feathers
- v. Body fat
- We don�t expect the environment to keep us warm, as opposed to the ectotherms.
c. What behaviors help poikilotherms maintain a fairly constant body temperature during their season of activity?
- i.Basking in the sun, cooling in the shade
- Regarding gene function, identify the two assumptions that Sapolsky criticizes in this essay.
- 1.The view that behavior is determined by an inherited genetic package
- 2.Genes as irresistible commanders
2. Long stretches of DNA do not code for proteins and do not get transcribed. As described by the author, state the function of at least some of this non-coding, non-transcribed DNA.
- �Some of it may be the instruction manual for how and when to activate those genes. They are regulatory elements, promoters, repressors, responsive elements.. and different biochemical messengers bring to those regulator elements and thereby alter the activities.
- NOTE: Sapolsky uses the phrase �junk DNA� to describe non-coding, non-transcribed DNA. Besides the very important function of at least some of this DNA discussed in this essay (see question #2), it is now known that the repetitious sequences of DNA once thought to be �junk� actually serve a structural function in the DNA molecule. In other words, there may still be some �junk� in DNA but much of what was once considered non-functional is, indeed, functional.
3. a) What per cent of DNA in mammals is non-coding, non-transcribed DNA? b) Which is more variable, coding or non-coding DNA? c) Considering the function of at least some of this non-coding, non-transcribed DNA described in this essay, what is the significance of the previous two answers?
- � 95%
- � Non-Coding
- � Genes can be convenient tools used by environmental factors to influence behavior� evolution is mostly about natural selection for different genetic sensitivities and responses to environments influences.
4. When the author describes various genetic possibilities, he frequently uses the phrase �you can design�. Who or, more appropriately, WHAT is �you�? HINT: See Notes for Lecture 4.
5. This essay is about the interaction of genes and environment or, to phrase it differently, the interaction between nature and nurture. According to Sapolsky, how does the environment affect genes and how does this affect behavior?
� Environment acts as a stressor that helps to bring out genes that are present. The environment regulates genetic activity.
6. Sapolsky gives examples of behaviors that are under the control of a single gene. What �type� of behavior (as discussed in lecture) are these?
- � The behavior of mating due to day length. As the days get longer, there is a gene that gets flipped on that induces the �gonads� so that mating begins.
- At the molecular level, the same nucleotide triplets code for the same amino acids in all organisms on this planet (as far as we now know). In evolutionary terms, what does this similarity indicate about otherwise very different organisms (e.g., prokaryotes and eurycaryotes)?
- � That we all have one common ancestor at some point.
2. Regarding the causes of evolution other than natural selection � mutation, gene flow and genetic drift � answer the following questions.
- � Mutations are heritable changes in a gene or a chromosome
- � Genetic drift is the change in allele frequency due to random chance associated with sexual reproduction
- � Migration is the movement of individuals between local populations
- � Gene flow is the movement of genes between populations
a) Which would typically increase genetic variation in a population and which would typically decrease genetic variation in a population? Explain.
- � Increase: gene flow, mutation
- � Decrease: genetic drift
b) Which one can practically reverse the effect of genetic drift? NOTE: There are two possible answers but only one is really practical!
� Gene flow
c) Discuss the implications of these evolutionary mechanisms with regard to the conservation of endangered or threatened species (i.e., species composed of widely separated, small populations).
- � Genetic drift is most important in small populations. There is typically a loss of alleles due entirely due to change.
- � Gene flow
3. Define inbreeding. What is inbreeding depression? In terms of classical Mendelian genetics (see REVIEW HANDOUT or CHAPTER 5), why is inbreeding so disadvantageous?
- Inbreeding is the mating of closely related individuals. Inbreeding depression is Offspring of closely related individuals are more likely to inherit rare, recessive, or deleterious genes that lower overall fitness
- Inbreeding is like evolutionary death, if you don�t reproduce its considered the same evolutionary.
4. Turtles have been successful organisms on this planet for millions and millions of years. Today, one of the most serious threats to their survival is the automobile. Wouldn�t it be advantageous for turtles to evolve the ability to run quickly to be able to avoid fast-moving cars? In the context of Section 5.8 (Adaptations Reflect Trade-offs and Constraints) of the text, describe why you would never expect this �adaptation� to occur.
�Its not something that�s been around long enough for the turtles to evolve to get away from. Its not an acting predator, its not stalking the turtles. It takes many years for things to evolve, its not in its genes to make this evolutionary leap.
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