Environmental System Sciences Exam #1

What is the principal difference between a natural resource such as crude oil and environmental service such as a stable climate? CH1

- A natural resource is something we get from the environment to meet our biological and economic needs and wants - Environmental services are natural processes that regulate conditions in the environment in ways that make the planet suitable for life.

How do the law of conservation and the laws of thermodynamics make biogeochemical cycles similar to and different from food chains?

- The relationship between flows and storages is governed by the law of conservation of matter: matter is neither created nor destroyed in a physical or chemical transformation. This implies that the amount of matter in a storage is determined by the rate at which matter flows into and out of that storage. -Consistent with the second law of thermodynamics, the solubility pump moves carbon between the atmosphere and ocean based on differences in concentrations. Basically matter in biogeochemical cycles can be recycled but energy in food chains cannot.

Give specific examples of how the people of Easter Island violated one or more of the principles of sustainability? CH1

- cutting down trees faster than they grow back - not understanding how introducing rats would influence the whole system - doing that weird thing where they had a competition for bird eggs and the winner could just tell anyone to give them what they wanted. - trading trees for moai. encouraging an unsustainable practice.

In the early 1900s some scientists argued that the order of living organisms violated the second law of thermodynamics. Evaluate this claim.

-living organisms are not a closed system. Just because some things in the universe get more ordered over time does not mean the universe as whole is becoming more ordered. -second law of thermodynamics, which states that the ability of energy to do useful work decreases as it is used to do work. As living organisms use their energy for maintenance, growth, reproduction, and protection, they must get new supplies of energy from their environment. -The second law of thermodynamics states that systems must use energy to maintain order against the constant tendency toward disorder. The use of energy to maintain order in a living system is termed maintenance respiration

Natural selection has been described as being blind. How can a random process generate traits that seem precisely designed for life in a given environment?

Basically, when a trait changes in an organism and that trait change increases an organisms overall fitness (chance of survival and reproduction) that trait will eventually take over and become common for a species because they will continue to survive and reproduce while organisms without that trait will die. These changes or mutations are completely random and only some will prove to be effective.

Characterize the relationships in the flow diagram for Easter Island (Figure 3-13) with respect to time lags. Describe the role of time lags in the collapse of the Easter Island civilization.

When new immigrants came to easter island the human population obviously increased. This caused an increase in the demand for agricultural land(short time lag). The more agricultural land the more amount of food supply the environment can produce. The more food supply the more humans are able to reproduce causing an increase in human population. Therefore a positive feedback loop. Time lags were especially evident for the forests in easter island. The rats started eating the seeds which the humans may have not fully noticed. The humans were also cutting trees at a higher rate, but they were not aware that trees were regrowing at a slower rate due to the lack of seeds. Over the course of the next 20 years few trees grew. Now the forests of easter island were sparse. It was too late for them to make any changes to reverse the damage done.

Animal life in aquatic biomes is most abundant where...

a solid substrate provides a place of anchorage and rocks or corals create vertical structure

Explain how the notion of carrying capacity that is used to analyze nonhuman populations must be modified to analyze human populations

Humans have a lot of brain power! We can get creative with out environment. Ingenuity may allow us to change the types of goods and services we depend on; the critical question is whether we have enough time to develop an alternative before a shortage can impose limits in a Malthusian sense. Given enough time, humans probably could replace nearly any environmental good or service. On the other hand, some replacements could take a long time, and before a solution arrives, the resulting shortage could shrink the population and reduce its well-being

How have humans altered the carbon cycle?

Humans have changed the carbon cycle by burning fossil fuels and altering land use. Due to these changes, the atmospheric concentration of carbon dioxide has increased over time. Scientists cannot balance the flow of carbon into and out of the atmosphere

how have humans altered the sulfur cycle?

Humans have changed the storages and flows of the sulfur cycle by mining and burning coal. These changes tend to cool the planet and increase the acidity of precipitation and waterways

Formulate a general rule to determine whether a feedback loop is positive or negative. Hint: The rule should be based on the number of relationships and the sign (positive or negative) of those relationships.

If there is an odd number of negative feedback loops than it is a negative feedback loop.

Early versus late succession community

In general, species that inhabit early successional communities tend to grow quickly and allocate much of their energy toward reproduction. Species that inhabit later successional communities tend to grow slowly and allocate less of their energy to reproduction -In general, early successional communities tend to have higher rates of net primary production, be less diverse, and lose more nutrients than later successional communities

During the first five years of the twenty-first century, oil prices rose from about $20 per barrel to well over $70 per barrel. Do you think a reductionist or integrated systems approach could best explain this price increase?

Integrated systems approach. A reductionist approach relies on the idea that all things in nature and human society can be explained by dissecting them into individual parts. We can't figure this out by just reading biology or chemistry textbook. We need a combination or physical science and economic and social sciences. Integrates systems approach uses both the physical aspects of the climate system and the economic aspects of activities that change global climate.

Vegetarians often are told to eat a combination of legumes (soybeans or peas), whole grains (rice or corn), and seeds or nuts (sesame or sunflower seeds). What is the reason for such a recommendation

Legumes have special nodules on their roots that house nitrogenfixing bacteria (See Video 6-3). This association gives legumes access to nitrogen, which allows these plants to have a higher protein content than nonlegumes. This high protein content makes legumes an important component of a vegetarian diet. By eating a diet that includes a variety of legumes, vegetarians can obtain all of the essential amino acids.

Flows

Movements between storages are known as flows, which can be either spontaneous flows or nonspontaneous flows. All biogeochemical cycles contain at least one nonspontaneous flow

Explain how temperature and the availability of light and water affect the shapes and life spans of leaves.

Natural selection favors a shape that allows each plant to thrive in its environment. Plants that live in areas with lots of water have thin leaves with lots of surface area. A large surface area allows the leaf to capture significant amounts of sunlight, which is needed to power photosynthesis. But a thin leaf transpires much water, so the plant must have access to sufficient water. The banana tree, which lives in tropical rain forests, has giant leaves. On the other hand, plants that live in areas with little water often have thick stubby leaves with relatively little surface area. This shape slows the rate at which water is lost from the leaf.

Resource optimist versus resource pessimist

Resource pessimists argue that exponential growth eventually outruns the environment's ability to provide goods and services, which will cause the human population to shrink and standards of living to decline. Resource optimists argue that ingenuity allows people to alleviate limits associated with environmental goods and services, which permits the human population to expand and its material standard of living to increase steadily

What are the sources of the energy that emanate from Earth's interior and the sun? What are their relative magnitudes?

Solar radiation: The energy emitted by the Sun becomes more diffuse as it travels through space. As solar radiation enters the atmosphere, it collides with gas molecules, dust, and other particles. These collisions cause it to scatter in various directions. Some of the radiation is turned back toward space in a process called reflection. Reflection in the atmosphere, cloud reflection, and earth surface reflection. 31 percent of the incoming solar radiation back to space. Heat from the interior of the earth: most of it is from the nuclear decay of elements. This large total of heat energy is much less than 1 percent of the energy that arrives from the Sun. So incoming solar radiation is the main source of energy for the physical systems of planet Earth

What would happen to the pattern of deep water circulation in a lake if water were completely transparent to solar energy (that is, if all of the light that struck the lake surface was absorbed by the lake bottom?

There would be no temperature profile so there would be no layer of aquatic environments. The whole ocean would be light and warm.

To help ecosystems recover from human disturbances, humans supplement succession through ecological restoration. What does that mean?

These processes focus on reestablishing the soil and plant and animal communities. Ecological restoration usually works in conjunction with succession rather than replacing it.

EROI

This ratio measures the amount of energy obtained relative to the amount of energy used to obtain it

What role do economic incentives play in the principles of sustainability? CH1

We can not expect businesses to act suitably with the caveat os losing profits. That is unreasonable. We must incentives both businesses and individuals to make and purchase sustainable products.

Why are equity and fairness important for sustainability? CH1

We can't make other people responsible for out actions. In addition, if we have more resources and funds we must help those who don't. We won't achieve a sustainable society without doing this

In some cases succession is replaced by catastrophic shifts between ecosystems. How does this happen.

We have described succession as a process that tends to return an ecosystem to its original state: The late successional community looks like the late successional community that was present before the disturbance. But some disturbances generate ecosystems that are very different from the previous ones. In short, certain ecosystems flip back and forth between alternative states. Changes between these states are not symmetric—reversing conditions that led to the switch often will not change the ecosystem back to its original state

adaptions

are behaviors or capabilities that allow species to thrive in some areas and fail in others

Why is a solid bottom important in aquatic biomes?

ask professor

Explain the similarity and differences between nitrogen fixation and photosynthesis

ask professor -in both nitrogen fixation and photosynthesis, nutrients are being converted into energy. Nitrogen fixation is inhibited in the pretense of oxygen, whereas photosynthesis produces oxygen, so the processes need to be separated. -both are non spontaneous (require energy)

Suppose you have two energy pyramids, both with five trophic positions. One pyramid is dominated by ectotherms; the other is dominated by endotherms. Assuming that the environmental concentration of pesticides was the same for both pyramids, in which pyramid would the top-level predator have the greatest concentration of pesticides

ask professor. Ectotherms because they have a higher ecological efficiency.

Which type of fish population is easier to manage—a population that is limited by density-dependent factors or a population that is limited by density-independent factors

ask professor: density-dependent

Suppose that two species differ greatly in their generation time — twenty minutes for species A and twenty years for species B. Which species is more likely to develop adaptations to a disturbance that has a frequency of about fifty years

ask professor: species A

Suppose that the Redfield ratio is 100:16:1 (C:N:P). If a plant has 300 units of carbon, 50 units of nitrogen, and 7 units of phosphorous, which is the limiting nutrient

carbon

Nutrients, available versus unavailable

carbon, hydrogen, oxygen, and smaller amounts of other elements Some of these nutrients are in forms that are usable by living organisms(available) if not then they are unavailable.

Give an example of a chemical, physical and nuclear change in matter.

chemical: hydrogen and oxygen combining to make water physical: dissolving sugar in water (individual sugar molecules are unchanged) nuclear: the decay of plutonium into uranium

How have humans altered the phosphorous cycle?

cycle by mining phosphorus. The extra phosphorus has increased biological activity, especially in aquatic environments. This too has led to eutrophication

Which type of species is more likely to grow exponentially—a species that lives in an early successional community or a species that lives in a late successional community

early successional community

eutrophication

excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.

Describe the first and second law of thermodynamics.

first: states that there is no increase or decrease in the quantity of energy in any energy conversion second: thermodynamics states that in all energy conversion processes energy loses its ability to do work and is degraded in quality.

Distinguish between fission and fusion.

fission: the division of a nucleus into two or more parts with masses of equal order of magnitude, usually accompanied by the emission of neutrons and gamma radiation. more neutrons and a large amount of energy are released fusion: a reaction between two light nuclei resulting in the production of a nuclear species heavier than either initial nucleus. a small amount of matter is destroyed and a large amount of energy is released

BRIEFLY describe facilitation, tolerance, and inhibition

inhibition.Through facilitation, species change the microenvironment in ways that make it less hospitable for themselves or more hospitable for the species that will replace them. Some species have adaptations that allow them to tolerate conditions that are unfavorable for other species; this generates successional changes between communities. Finally, some species create conditions that inhibit other species, which tends to stabilize a community and thereby slow succession

species range

is determined by the area where it can obtain enough energy for growth, storage, maintenance, protection, and reproduction. Its ability to obtain this energy is determined by how well its adaptations suit a given climate and the other species that live in the area

Succession

is the process by which ecosystems respond to disturbances. Succession can be fairly predictable because the microenvironment tends to change in an orderly process. These changes are important because they tend to determine the adaptations that are suited for an environment

The activity of terrestrial animals also is shaped by the...

length of the growing season. Where the growing season extends throughout the year, many animals are active year-round. In areas where water or temperature limits the growing season, animals often avoid these limits by hibernating or migrating

what are the 6 uses of energy

maintenance, growth, storage, reproduction, protection, and obtaining more energy from the environment organisms have varying strategies on how to allocate energy. These depend on so many things regarding an organism environment and climate.

describe gross primary production

measures the amount of organic energy generated by autotrophs per unit area per unit time, and net primary production represents the amount of energy that is converted to structures that can be consumed by heterotrophs. This energy is lost from the food chain as organisms use energy and as energy is transferred between organisms. The length of the food chain is positively related to net primary production and ecological efficiency

Describe the basic forms of energy and give an example of each

mechanical energy: is the energy of the organized motion of matter, and typically is the energy that drives the work done by machines. Mechanical energy includes potential energy(energy of position) and kinetic energy(energy of motion). wind mill Electrical energy or electricity: is the force of charged particles acting on one another thermal energy: energy carried by heat flow chemical energy: is energy that is stored in the arrangement of elements(produced or absorbed in chemical reactions), such as the energy stored in fossil fuels (e.g. gasoline) or in carbohydrates (e.g. simple sugars). nuclear energy: is the energy that binds the protons and neutrons together in the nuclei of atoms.

If Earth rotated to the west, how would the pattern of surface winds and surface ocean currents change relative to their current directions?

office hours: Trade winds would now blow from west to east instead of east to west.

Distinguish power from energy.

power: is the rate at which work is done, or, more generally, the rate at which energy is used energy: is the "capacity to do work."

On your next trip to the supermarket or convenience store, choose one of the food items you purchase and look at the nutrition label. What essential trace nutrients does it contain

red meat. copper, iron, phosphorus, magnesium and zinc

Categorize the following species as members of early successional communities or late successional communities: roaches, dandelions, Siberian tigers, and oak trees. Explain your choices

roaches and dandelions: early successional community, because they have many small offspring, reproduce when they are young, and a lot of offspring will die before reaching reproductive age. Dandelion seed dispersal is long by wind. Siberian tigers and oak trees: late successional communities, because tigers have a smaller number of offspring and they reproduce when they are older. They are large when they mature. Oak trees only have a few seeds that are large and do not disperse very far.

Aquatic biomes are shaped by...

salinity, temperature, and the availability of light, nutrients, and oxygen

What is a radioisotope?

short for radioactive isotope; an unstable isotope of an element that decays or disintegrates spontaneously, emitting radiation. This means that special precautions must be used to isolate them from the damaging radiation they release, often for long periods of time

As will be explained in Chapter 20, oil is derived from living organisms that lived millions of years ago. Much of the world's oil supply is found in the Persian Gulf, where there is little biological activity to serve as a source of oil. How can you explain this seeming contradiction?

the continents were part of a continuous landmass a long time ago and since have moved to their present positions. The source of this oil could have been prior to the moving of the plate tectonics.

Biogeochemical cycles consist of 4 storages, what are they

the crust, biota, atmosphere, and oceans

Population growth is determined by... Role of density dependent and density independent factors how that leads us to carrying capacity

the difference between the birthrate and the death rate. Both of these rates are determined by density-independent and density-dependent factors. When density-dependent factors are unimportant, populations have the potential to grow geometrically or exponentially. As populations expand, density-dependent factors become more important, which slows population growth. The point at which population growth stops due to density-dependent factors is termed carrying capacity

How would you define your ecological footprint? CH1

the impact of a person or community on the environment, expressed as the amount of land required to sustain their use of natural resources.

What does it mean to apply an energy and materials balance to the production of a good or service?

the quantity of energy and materials that enter a process must be equal to (balanced by) an equivalent amount that leaves the process Calculate how much of each material and how much energy before the production of a good or service. This should match up to the output

The Haber-Bosch process uses large amounts of natural gas. Explain why this is so.

to split atmospheric nitrogen and convert it to ammonia. This ammonia is used largely as the nitrogenous fertilizer that has powered the large increase in crop yields.

What does it mean to take a "systems perspective" in environmental decision-making? CH1

understanding that the effect of changing something in an environment has more consequences that just the direct ones. There indirect consequences that we must acknowledge by looking at the entire environment as a system not s individual parts.

Explain the concept of energy return on investment (EROI). How would you calculate the EROI for a coalmine? CH1

-is a ratio for describing a measure of energy produced in relation to the energy used to create it. -how much coal energy one is able to mine divided by the energy one used to mine it

Explain the differences among facilitation, tolerance, and inhibition. Give at least one example of each

-Facilitation states that species in early and middle successional communities change their microenvironments in ways that make them less hospitable for their own needs or more hospitable to species that inhabit later successional communities. In other words, species create the conditions for their own demise -tolerance model: suggests that all species in the succession are capable of establishing on a newly disturbed site, although with varying successes in terms of the rapid attainment of a large population size and biomass. In contrast with predictions of the facilitation model, the early occupants of the site do not change environmental conditions in ways that favor the subsequent invasion of later-successional species. Rather, with increasing time, the various species sort themselves out through their differing tolerances of the successionally increasing intensity of biological stresses associated with competition. In the tolerance model, competition-intolerant species are relatively successful early in succession when site conditions are characterized by a free availability of resources. However, these species are eliminated later on because they are not as competitive as later species, which eventually develop a climax community -any species can start the process of succession. As with the tolerance model, the first species to arrive depends on its ability to disperse and the luck of being in the right place at the right time. But being first is critical in the inhibition model. Whichever species establishes itself first can persist for a relatively long period by inhibiting the growth of other species. -Inhibition is defined as a direct or indirect harmful effect of one species on another. Because of this effect, new species appear only if the first species to arrive is removed by another disturbance or if another species can outlast the first species due to a longer life span

Explain why there is a nonlinear relationship between the spatial scale of disturbances and the time required for recovery

-In general, recovery time is related positively to disturbance spatial scale -The larger spatial scale of a disturbance the longer it will take for the system to recover.

Some species migrate long distances to their breeding grounds. How could natural selection favor such behavior

-Many migrants take advantage of favorable food and weather conditions offered in certain areas during very limited time periods. In other cases, the resources needed in different life stages may be found in different locations. They also avoid the less than ideal conditions of their current climate. -It may make a lot of energy to get somewhere, but the climate in that new location will allow an organism to be more productive. -The energy return on investment is greater than one in the whole scheme of migrating. - Prior to leaving for migration animals will store of energy in fats.

What is the Law of the Conservation of Matter? Why is it a foundation of environmental science?

-Matter can change form through physical and chemical changes, but through any of these changes, matter is conserved. -all of the elements society extracts ultimately are returned to the air, water, or land after their use. This is especially important for elements that have harmful effects on the environment.

Explain the following contradiction: The second law of thermodynamics states that the universe as a whole tends toward a greater state of disorder, but the environment is filled with systems that display predictable behavior.

-Storages and flows operate in a way that is consistent with the laws of thermodynamics. -They are spontaneous and non spontaneous flows of materials and energy and they depend on the new supplies of energy to system The subsystems of the entire universe can be either increasing or decreasing entropy, but the entire universe as a whole is always increasing entropy.

habitat versus niche

-The area where a species lives is its habitat, and its role in that habitat is its niche. -Two species generally cannot share the same niche indefinitely. Natural selection favors adaptations that allow species to avoid competition by changing their niche relative to similar species

Without the effects of disease or disturbance, why is it impossible for two species to share the same exact niche for extended periods? Why might natural selection favor changes that reduce interactions between species rather than a battle to the finish in which one species becomes extinct

-The competitive exclusion principle states that no two species can share the same exact niche indefinitely unless other factors limit the density of the better competitor. Over time, natural selection favors changes that reduce the degree to which species share the same niche.

What is an energy convertor?

-a device that converts energy to work -To do work, energy must be converted from one form to another.

Explain how the combination of climatic conditions and the distribution of endotherms affects the range of ectotherms in the United States.

-areas with little rainfall tend to have more ectotherms -The low basal metabolic rate of ectotherms is a useful adaptation for animals that live in hot dry environments where net primary production is relatively low. These areas do not suit endotherms because their high basal metabolic rate implies that they need a lot of food. -This situation is reversed in the eastern states, where greater precipitation increases net primary production, raising the amount of energy available. Endotherms can capture a relatively large share of this energy because their ability to maintain body temperature lengthens the time that they can be active. Fewer species of lizards may be found in the Southeast because ectotherms find it difficult to compete with endotherms where food energy supplies are abundant

What were the principal ways that the Easter Islanders depleted the resources of their environment? CH1

-be a shortage of food caused by population growth and degradation of the island's environmental resources (people had to fight over food completely damaging the social structure the island had) -Polynesian rat had no predators so the population grew exponentially. They ate seeds of palm trees decreasing their population.

Population is supposed to stop growing when it reaches its carrying capacity. But populations in the real world often exceed their carrying capacity. Explain how this is possible

-carrying capacity is the maximum number of individuals of a population that can be maintained indefinitely by the environmental goods and services that are generated by a given area of the environment. Indefinitely is the important word here. -Time lags in the relationship between population growth and density-dependent factors allow many real world populations to fluctuate around their carrying capacity -If a population exceeds carrying capacity, the ecosystem may become unsuitable for the species to survive indefinitely. If the population exceeds the carrying capacity for a long period of time, resources may be completely depleted.

Define sustainability. What role does concern for future generations play in the notion of sustainability? CH1

-conditions under which the quality of human life is improved while living within the carrying capacity of supporting natural systems, thus meeting the needs of the present without compromising the ability of future generations to meet their own needs

What is the equation for energy efficiency?

Efficiency = useful energy output/total energy input

Explain why light and nutrients often are separated in aquatic biomes. Explain the mechanisms that create areas where light and nutrients are abundant in the same layer of the water column.

-most nutrients are located below the euphotic zone. Nutrients fall downward with waste materials such as fecal pellets and with dead organic matter. Once they fall below the euphotic zone, their return is slowed by the thermocline. This layering separates the availability of light (near the surface) and nutrients (on the bottom), thus limiting the productivity of many aquatic ecosystems -In many temperate lakes nutrients mix into the euphotic zone during the spring and fall due to changes in solar radiation and winds. These factors cannot return nutrients to the euphotic zone in most marine environments because the water is too deep. Instead most marine biological activity occurs in relatively small areas where the ocean is shallow, where winds or water currents bring bottom water to the surface in zones of upwelling, or where rivers meet the ocean

On land, the geographic distribution of plants is determined by the...

-the availability of light, water, and temperature. The availability of light is determined primarily by latitude and secondarily by the structure of the local plant community. The availability of water is determined by the balance between precipitation and potential evaporation. This balance is correlated with latitude. Finally, temperature has its greatest effect by determining the length of the growing season. This too generally varies by latitude

What is the electromagnetic spectrum?

-the range of wavelengths or frequencies over which electromagnetic radiation extends. -The visible white light that reaches Earth can be passed through a prism to produce the full spectrum of colors from red to blue -the warmth we feel from the sun is energy from parts of the electromagnetic spectrum that are not visible.

Explain the conditions under which an ecosystem with a high rate of disturbance may have a low turnover rate

-turnover rate is the average time required to disturb an entire area -If an ecosystem has a lot of biodiversity it will take longer for the ecosystem to be seriously damaged by the disturbances.

Describe the four principles of sustainability, and give two examples of each? CH1

1)A sustainable society does not use natural resources or produce wastes faster than they are regenerated or assimilated by the environment - overfishing - cutting down trees faster then they grow back 2) A sustainable society must account for the highly interconnected relationship with its environment and how these connections can cause decisions to succeed or fail - the clean air act causing acid rain in other parts of the country - introducing rats to Easter island causing the depletion of palm trees 3) The first two principles of sustainability must be meshed with the ethical and moral principles that govern fairness among nations, between genders, and among the current and future generations - poorer nations should not be held responsible for the actions of the more developed nations who are responsible for large amounts of natural resource depletion and energy use - poorer nations are worried about where their dinner is coming from unlike developing nations. developing nations need to help them and provide them with the tools to be sustainable 4) Social incentives must reward those who act in a sustainable way and punish those who act in a non-sustainable manner - negative externally is a cost associated with a product that is not included the price of the product. So if someone is able to benefit from buying something for cheap when they are actually costing the environment problems - environmental performance bond encourages firms and businesses to act and build sustainably

give an overview of food webs and food chains

All food webs start with autotrophs. Energy then moves through grazers and consumers. All food chains end with detritivores. The location of an organism in this transfer of energy is known as its trophic position

Explain the circulation of Earth's atmosphere, oceans, and surface materials in terms of the convection cell shown in Figure 4-6.

Convection currents form because a heated fluid expands, becoming less dense. The less-dense heated fluid rises away from the heat source. As it rises, it pulls cooler fluid down to replace it. This fluid in turn is heated, rises and pulls down more cool fluid. ocean: Cold polar water is drawn down from higher latitudes and sinks to the ocean bottom, pulled down toward the equator as lighter, warmer water rises to the ocean's surface. The warmer water is pulled northward to replace the cold water that's been pulled southward. This process distributes heat and soluble nutrients around the world. atmosphere: atmosphere: The sun heats the air near the earth's equator, which becomes less dense and rises upward. As it rises, it cools and becomes less dense than the air around it, spreading out and descending toward the equator again. These constantly moving cells of warm and cold air, known as Hadley Cells, drive the continual circulation of air at the earth's surface that we call wind. Atmospheric convection currents are also what keep clouds aloft. surface materials: As the rock loses heat into the earth's crust, it becomes relatively cooler and more dense, sinking back down to the core. These constantly circulating cells of hotter and cooler molten rock are thought to help heat the surface.

Disturbances

Disturbances vary in frequency and spatial scale, and their product determines the rate at which an ecosystem is turned over. Disturbance frequency and the variability around this frequency influence whether plants and animals have adaptations to cope with disturbances

Effect of diversity of functional groups and food webs

Diversity of functional groups increases the ability of ecosystems to recover from disturbances, while diverse food webs and the prevalence of weak interactions increase an ecosystem's ability to resist disturbances

Explain the difference between ecological stability, resistance, and resilience. How are they affected by diversity

Ecological stability is a system's ability to return to a set point (equillibirum) after a disturbance or perpetuation. Resistance is how well a system handles a disturbance. A very resistant system would show little change or shift even when hit with a pretty strong disturbance (diversity in . Resilience evaluates how well a system can return to a set point even when it is moved very far from that set point. Theorthetically, a system could not be very resistant (meaning the system does react to the disturbance), but it could still be resilient (in the sense that the system does eventually return to the set point. On the other hand, a system could be very resistant (meaning it takes a lot of energy to disturb the system), but not be resilient (meaning when the system is finally disturbed it will not return to the set point). High levels of resistance and resilience contribute to making an ecosystem more stable in general. High levels of diversity, specifically biodiversity, will make a system more stable, resistant, and resilient.

What is entropy? Why is it important in environmental science?

Entropy is the degree of order or organization in a system. -entropy overall is always increasing. our world is always getting more disorganized. energy conversions always release waste heat adding to disorder.