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1.In a predator-prey relationship, the predator is an organism that eats another organism (the prey).
2. Symbiosis is a close and long-term interaction between two species in an ecosystem. Types of symbiosis include
mutualism, commensalism, and parasitism.
3. Competition can occur within or between species in an ecosystem where there are limited resources.
4. Resource partitioning— using the resources in different ways, places, or at different times—can reduce the negative impact
of competition on survival.

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1. biome: a large naturally occurring community of flora and fauna occupying a major habitat, e.g. forest or tundra.
2. Examples: grasslands, forests, deserts, and tundra
3. The global distribution of nonmineral terrestrial natural resources such as water and trees for lumber, varies because of some combination of climate, geography, latitude and altitude, nutrient availability and soil.
4. The worldwide distribution of biomes is dynamic; the distribution has changed in the past and may again shift as a result of global climate changes.

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1. Freshwater biomes include streams, rivers, ponds, and lakes. These freshwater biomes are a vital resource for
drinking water.
2. Marine biomes include oceans, coral reefs, marshland, and estuaries.
3. Algae in marine biomes supply a large
portion of the Earth’s oxygen, and also take in carbon dioxide from the atmosphere.
4. The global distribution of nonmineral marine natural resources, such as different types of fish, varies because of
some combination of salinity, depth, turbidity, nutrient availability, and temperature.

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1. The carbon cycle is the movement of atoms and molecules containing the element carbon between sources and
sinks.
2. Some of the reservoirs in which carbon compounds occur in the carbon cycle hold those compounds for long
periods of time, while some hold them for relatively short periods of time.
3. Carbon cycles between photosynthesis and cellular respiration in living things.
4. Plant and animal decomposition have led to the storage of carbon over millions of years. The burning of fossil
fuels quickly moves that stored carbon into atmospheric carbon, in the form of carbon dioxide.

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1. The nitrogen cycle is the movement of atoms and molecules containing the element nitrogen between sources
and sinks.
2. Most of the reservoirs in which nitrogen compounds occur in the nitrogen cycle hold those compounds for relatively short periods of time.
3. Nitrogen fixation is the process in which atmospheric nitrogen is converted into a form of nitrogen (primarily ammonia) that is available for uptake by plants and that can be synthesized into plant tissue. 85
4. The atmosphere is the major reservoir of nitrogen.

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1. The phosphorus cycle is the movement of atoms and molecules containing the element phosphorus between
sources and sinks.
2. The major reservoirs of phosphorus in the phosphorus cycle are rock and sediments that contain phosphorus-bearing minerals.
3. There is no atmospheric component in the phosphorus cycle, and the limitations this imposes on the return of
phosphorus from the ocean to land make phosphorus naturally scarce in aquatic and many terrestrial ecosystems.
4. In undisturbed ecosystems, phosphorus is the limiting factor in biological systems.

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1. The hydrologic cycle, which is powered by the sun, is the movement of water in its various solid, liquid, and
gaseous phases between sources and sinks.
2. The oceans are the primary reservoir of water at the Earth’s surface, with ice caps and groundwater acting as
much smaller reservoirs.

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1. Primary productivity is the rate at which solar energy (sunlight) is converted into organic compounds via photosynthesis over a unit of time.
2. Gross primary productivity is the total rate of photosynthesis in a given area.
3. Net primary productivity is the rate of energy storage by photosynthesizers in a given area, after subtracting the
energy lost to respiration.
4. Productivity is measured in units of energy per unit area per unit time (e.g., kcal/m2/yr). 74-6
5. Most red light is absorbed in the upper 1m of water, and blue light only penetrates deeper than 100m in the clearest water. This affects photosynthesis in aquatic ecosystems, whose photosynthesizers have adapted
mechanisms to address the lack of visible light.

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1. All ecosystems depend on a continuous inflow of high-quality energy in order to maintain their structure and function of transferring matter between the environment and organisms via biogeochemical cycles.
2. Biogeochemical cycles are essential for life and each cycle demonstrates the conservation of matter
3. In terrestrial and near-surface marine communities, energy flows from the sun to producers in the lowest trophic
levels and then upward to higher trophic levels.

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1. The 10% rule approximates that in the transfer of energy from one trophic level to the next, only about 10% of the
energy is passed on.
2. The loss of energy that occurs when energy moves from lower to higher trophic levels can be explained through
the laws of thermodynamics.

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1. A food web is a model of an interlocking pattern of food chains that depicts the flow of energy and nutrients in two
or more food chains.
2. Positive and negative feedback loops can each play a role in food webs. When one species is removed from or
added to a specific food web, the rest of the food web can be affected.

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1. Biodiversity in an ecosystem includes genetic, species, and habitat diversity
2. The more genetically diverse a population is, the better it can respond to environmental stressors.
3. A population bottleneck can lead to a loss of genetic diversity.
4. Ecosystems that have a larger number of species are more likely to recover from disruptions.
5. Loss of habitat leads to a loss of specialist species, followed by a loss of generalist species. It also leads to reduced numbers of species that have large territorial requirements.
6. Species richness refers to the number of different species found in an ecosystem

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1. There are four categories of ecosystem services: provisioning, regulating, cultural, and supporting.
2. Anthropogenic activities can disrupt ecosystem services, potentially resulting in economic and ecological
consequences.

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1. Island biogeography is the study of the ecological relationships and distribution of organisms on islands, and of
these organisms’ community structures. Islands have been colonized in the past by new species arriving from elsewhere.
2. Many island species have evolved to be specialists versus generalists because of the limited resources, such as food and territory, on most islands. The long-term survival of specialists may be jeopardized if and when invasive species, typically generalists, are introduced and outcompete the specialists.

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1. Ecological tolerance refers to the range of conditions, such as temperature, salinity, flow rate, and sunlight that an
organism can endure before injury or death results. Ecological tolerance can apply to individuals and to species.

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1. Natural disruptions to ecosystems have environmental consequences that may, for a given occurrence, be as great as, or greater than, many human-made disruptions
2. Earth system processes operate on a range of scales in terms of time. Processes can be periodic, episodic, or
random.
3. Earth’s climate has changed over geological time for many reasons
4. Sea level has varied significantly as a result of changes in the amount of glacial ice on Earth over geological time.
Major environmental change or upheaval commonly results in large swathes of habitat changes.
5. Wildlife engages in both short- and long-term migration for a variety of reasons, including natural disruptions.

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1. Organisms adapt to their environment over time, both in short- and long-term scales, via incremental changes at
the genetic level.
2. Environmental changes, either sudden or gradual, may threaten a species’ survival, requiring individuals to alter behaviors, move, or perish.

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1. There are two main types of ecological succession: primary and secondary succession.
2. A keystone species in an ecosystem is a species whose activities have a particularly significant role in
determining community structure.
3. An indicator species is a plant or animal that, by its presence, abundance, scarcity, or chemical composition, demonstrates that some distinctive aspect of the character or quality of an ecosystem is present
4. Pioneer members of an early successional species commonly move into unoccupied habitat and over time adapt to its particular conditions, which may result in the origin of new species.
5. Succession in a disturbed ecosystem will affect the total biomass, species richness, and net productivity over
time.

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1. Specialist species tend to be advantaged in habitats that remain constant, while generalist species tend to be
advantaged in habitats that are changing.

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1. K-selected species tend to be large, have few offspring per reproduction event, live in stable environments, expend significant energy for each offspring, mature after many years of extended youth and parental care,
have long life spans/life expectancy, and reproduce more than once in their lifetime. Competition for resources
in K-selected species’ habitats is usually relatively high.
2. r-selected species tend to be small, have many offspring, expend or invest minimal energy for each offspring, mature early, have short life spans, and may reproduce only once in their lifetime. Competition for resources in r-selected species’ habitats is typically relatively low.
3. Biotic potential refers to the maximum reproductive rate of a population in ideal conditions.
4. Many species have reproductive strategies that are not uniquely r-selected or K-selected, or they change in different conditions at different times.
5. K-selected species are typically more adversely affected by invasive species than r-selected species, which are minimally affected by invasive species. Most invasive species are r-selected species.

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1. A survivorship curve is a line that displays the relative survival rates of a cohort—a group of individuals of the
same age—in a population, from birth to the maximum age reached by any one cohort member. There are Type
I, Type II, and Type III curves.
2. Survivorship curves differ for K-selected and r-selected species, with K-selected species typically following a Type I or Type II curve and r-selected species following a Type III curve

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1. When a population exceeds its carrying capacity (carrying capacity can be denoted as K), overshoot occurs. There are environmental impacts of population overshoot, including resource depletion.
2. A major ecological effect of population overshoot is dieback of the population (often severe to catastrophic) because the lack of available resources leads to famine, disease, and/or conflict.

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3.5 Population Growth and Resource Availability 

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3.5 Population Growth and Resource Availability 

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1. Population growth is limited by environmental factors, especially by the available resources and space.
2. Resource availability and the total resource base are limited and finite over all scales of time.
3. When the resources needed by a population for growth are abundant, population growth usually accelerates.
4. When the resource base of a population shrinks, the increased potential for unequal distribution of resources will ultimately result in increased mortality, decreased fecundity, or both, resulting in population growth declining
to, or below, carrying capacity.

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1. Population growth rates can be interpreted from age structure diagrams by the shape of the structure.
2. A rapidly growing population will, as a rule, have a higher proportion of younger people compared to stable or
declining populations.

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1. Total fertility rate (TFR) is affected by the age at which females have their first child, educational opportunities
for females, access to family planning, and government acts and policies.
2. If fertility rate is at replacement levels, a population is considered relatively stable.
3. Factors associated with infant mortality rates include whether mothers have access to good healthcare and nutrition. Changes in these factors can lead to changes in infant mortality rates over time

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1. Birth rates, infant mortality rates, and overall death rates, access to family planning, access to good nutrition,
access to education, and postponement of marriage all affect whether a human population is growing or
declining
2. Factors limiting global human population include the Earth’s carrying capacity and the basic factors that limit human population growth as set forth by Malthusian theory
3. Population growth can be affected by both density-independent factors, such as major storms, fires, heat
waves, or droughts, and density-dependent factors, such as access to clean water and air, food availability, disease transmission, or territory size.
4. The rule of 70 states that dividing the number 70 by the percentage population growth rate approximates the
population’s doubling time

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1. The demographic transition refers to the transition from high to lower birth and death rates in a country or region as development occurs and that country moves from a preindustrial to an industrialized economic system. This transition is typically demonstrated through a four-stage demographic transition model (DTM).
2. Characteristics of developing countries include higher infant mortality rates and more children in the workforce than developed countries.

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1. Convergent boundaries can result in the creation of mountains, island arcs, earthquakes, and volcanoes.
2. Divergent boundaries can result in seafloor spreading, rift valleys, volcanoes, and earthquakes.
3. Transform boundaries can result in earthquakes.
4. Maps that show the global distribution of plate boundaries can be used to determine the location of volcanoes, island arcs, earthquakes, hot spots, and faults.
5. An earthquake occurs when stress overcomes a locked fault, releasing stored energy.

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1. Soils are formed when parent material is weathered, transported, and deposited.
2. Soils are generally categorized by horizons based on their composition and organic material.
3. Soils can be eroded by winds or water.
4. Protecting soils can protect water quality as soils effectively filter and clean water that moves through them.

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1. Water holding capacity—the total amount of water soil can hold—varies with different soil types.
2. Water retention contributes to land productivity and fertility of soils.
3. The particle size and composition of each soil horizon can affect the porosity, permeability, and fertility of
the soil.
4. There are a variety of methods to test the chemical, physical, and biological properties of soil that can aid in a variety of decisions, such as irrigation and fertilizer requirements.
5. A soil texture triangle is a diagram that allows for the identification and comparison of soil types based on their percentage of clay, silt, and sand.

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1. The atmosphere is made up of major gases, each with its own relative abundance.
2. The layers of the atmosphere are based on temperature gradients and include the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

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1. Global wind patterns primarily result from the most intense solar radiation arriving at the equator, resulting in density differences and the Coriolis effect.

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1. Characteristics of a given watershed include its area, length, slope, soil, vegetation types, and divides with
adjoining watersheds.

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4.7 Solar Radiation and Earth's Seasons 

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4.7 Solar Radiation and Earth's Seasons 

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1. Incoming solar radiation (insolation) is the Earth’s main source of energy and is dependent upon the angle of the sun's rays.
2. The angle of the sun’s rays determines the intensity of the solar radiation. Due to the shape of the Earth, the latitude that is directly horizontal to the solar radiation receives the most intensity.
3. The highest solar radiation per unit area is received at the equator and decreases toward the poles.
4. The solar radiation received at a location on the Earth’s surface varies seasonally, with the most radiation received during the location’s longest summer day and the least on the shortest winter day.
5. The tilt of Earth’s axis of rotation causes the Earth’s seasons and the number of hours of daylight in a particular location on the Earth’s surface.

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1. Weather and climate are affected not only by the sun’s energy but by geologic and geographic factors,
such as mountains and ocean temperature.
2. A rain shadow is a region of land that has become drier because a higher elevation area blocks precipitation from reaching the land.

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1. El Niño and La Niña are phenomena associated with changing ocean surface temperatures in the Pacific
Ocean. These phenomena can cause global changes to rainfall, wind, and ocean circulation patterns.
2. El Niño and La Niña are influenced by geological and geographic factors and can affect different locations
in different ways.

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1. The tragedy of the commons suggests that individuals will use shared resources in their own self-interest rather than in keeping with the common good, thereby depleting the resources.

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1. Clearcutting can be economically advantageous but leads to soil erosion, increased soil and stream temperatures, and flooding.
2. Forests contain trees that absorb pollutants and store carbon dioxide. The cutting and burning of trees releases carbon dioxide and contributes to climate change.

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1. The Green Revolution started a shift to new agricultural strategies and practices in order to increase food production, with both positive and negative results. Some of these strategies and methods are mechanization, genetically modified organisms (GMOs), fertilization, irrigation, and the use of pesticides.
2. Mechanization of farming can increase profits and efficiency for farms. It can also increase reliance on fossil fuels.

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1. Agricultural practices that cause environmental damage include tiling, slash-and-burn farming, and the use
of fertilizers.

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1. The largest human use of freshwater is for irrigation (70%).
2. Furrow irrigation involves cutting furrows between crop rows and filling them with water. This system is inexpensive, but about 1/3 of the water is lost to evaporation and runoff. Flood irrigation involves flooding an agricultural field with water. This system sees about 20% of the water lost to evaporation and runoff. This can also lead to waterlogging of the soil. Spray irrigation involves pumping groundwater into spray nozzles across an agricultural field. This system is more efficient than flood and furrow irrigation, with only 1/4 or less of the water lost to evaporation or runoff. However, spray systems are more expensive than flood and furrow irrigation, and also requires
energy to run. Drip irrigation uses perforated hoses to release small amounts of water to plant roots. This system is the most efficient, with only about 5% of water lost to evaporation and runoff. However, this system is expensive and so is not often used.
3. Waterlogging occurs when too much water is left to sit in the soil, which raises the water table of groundwater and inhibits plants' ability to absorb oxygen through their roots.
4. Salinization occurs when the salts in groundwater remain in the soil after the water evaporates. Over time, salinization can make soil toxic to plants.
5. Aquifers can be severely depleted if overused for agricultural irrigation, as has happened to the Ogallala
Aquifer in the central United States.

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1. One consequence of using common pest-control methods such as pesticides, herbicides, fungicides, rodenticides, and insecticides is that organisms can become resistant to them through artificial selection.
Pest control decreases crop damage by pest and increases crop yields.
2. Crops can be genetically engineered to increase their resistance to pests and diseases. 3. However, using genetically engineered crops in planting or other ways can lead to loss of genetic diversity of that particular crop.

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1. Methods of meat production include concentrated animal feeding operations (CAFOs), also called feedlots, and free-range grazing.
2. Meat production is less efficient than agriculture; it takes approximately 20 times more land to produce the same amount of calories from meat as from plants.
3. Concentrated animal feeding operation (CAFOs) are used as a way to quickly get livestock ready for slaughter. They tend to be crowded, and animals are fed grains or feed that are not as suitable as grass. Additionally, feedlots generate a large amount of organic waste, which can contaminate ground and
surface water. The use of feedlots are less expensive than other methods, which can keep costs to
consumers down.
4. Free range grazing allows animals to graze on grass during their entire lifecycle. Meat from free range animals tends to be free from antibiotics and other chemicals used in feedlots. Organic waste from these
animals acts as fertilizer. Free range grazing requires large areas of land and the meat produced is more expensive for consumers.
5. Overgrazing occurs when too many animals feed on a particular area of land. Overgrazing causes loss of vegetation, which leads to soil erosion.
6. Overgrazing can cause desertification. Desertification is the degradation of low precipitation regions toward
being increasingly arid until they become deserts.
7. Less consumption of meat could reduce CO2, methane, and N2O emissions; conserve water; reduce the use of antibiotics and growth hormones; and improve topsoil.

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1. Overfishing has led to the extreme scarcity of some fish species, which can lessen biodiversity in aquatic
systems and harm people who depend on fishing for food and commerce.

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1. As the more accessible ores are mined to depletion, mining operations are forced to access lower grade ores. Accessing these ores requires increased use of resources that can cause increased waste and
pollution.
2. Surface mining is the removal of large portions of soil and rock, called overburden, in order to access the ore underneath. An example is strip mining, which removes the vegetation from an area, making the area more susceptible to erosion.
3. Mining wastes include the soil and rocks that are moved to gain access to the ore and the waste, called slag and tailings that remain when the minerals have been removed from the ore.
4. Mining helps to provide
low cost energy and material necessary to make products. The mining of coal can destroy habitats, contaminate ground water, and release dust particles and methane.
5. As coal reserves get smaller, due to a lack of easily accessible reserves, it becomes necessary to access coal through subsurface mining, which is very expensive.

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1. Urbanization can lead to depletion of resources and saltwater intrusion in the hydrologic cycle.
2. Urbanization, through the burning of fossil fuels and landfills, affects the carbon cycle by increasing the amount of carbon dioxide in the atmosphere.
3. Impervious surfaces are human-made structures—such as roads, buildings, sidewalks, and parking lots —that do not allow water to reach the soil, leading to flooding.
4. Urban sprawl is the change in population distribution from high population density areas to low density suburbs that spread into rural lands, leading to potential environmental problems.

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1. Ecological footprints compare resource demands and waste production required for an individual or a
society.

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1. Sustainability refers to humans living on Earth and their use of resources without depletion of the resources for future generations. Environmental indicators that can guide humans to sustainability include
biological diversity, food production, average global surface temperatures and CO2 concentrations, human population, and resource depletion.
3. Sustainable yield is the amount of a renewable resource that can be taken without reducing the available
supply.

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1. Methods to increase water infiltration include replacing traditional pavement with permeable pavement,
planting trees, increased use of public transportation, and building up, not out.

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1. Integrated pest management (IPM) is a combination of methods used to effectively control pest species
while minimizing the disruption to the environment. These methods include biological, physical, and limited
chemical methods such as biocontrol, intercropping, crop rotation, and natural predators of the pests.
2. The use of integrated pest management (IPM) reduces the risk that pesticides pose to wildlife, water supplies, and human health.
3. Integrated pest management (IPM) minimizes disruptions to the environment and threats to human health but can be complex and expensive.

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1. The goal of soil conservation is to prevent soil erosion. Different methods of soil conservation include contour plowing, windbreaks, perennial crops, terracing, no-till agriculture, and strip cropping.
2. Strategies to improve soil fertility include crop rotation and the addition of green manure and limestone.
3. Rotational grazing is the regular rotation of livestock between different pastures in order to avoid overgrazing in a particular area.

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1. Aquaculture can contaminate wastewater, and fish that escape may compete or breed with wild fish. The density of fish in aquaculture can lead to increases in disease incidences, which can be transmitted to wild fish.

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EU policies on oceans, fisheries and aquaculture.

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1. Some of the methods for mitigating deforestation include reforestation, using and buying wood harvested by ecologically sustainable forestry techniques, and reusing wood.
2. Methods to protect forests from pathogens and insects include integrated pest management (IPM) and the
removal of affected trees.
3. Prescribed burn is a method by which forests are set on fire under controlled conditions in order to reduce the occurrence of natural fires.