Principles of Ecology Final Exam Review

Rutgers NB Ecology Final Flashcards

Explain how interactions between organisms and their environment can affect other organisms and potentially lead to unexpected consequences. (Part 1)

Laboratory and field experiments on the effects of parasites on amphibian deformities illustrate how events in nature can be connected with one another.

Explain how interactions between organisms and their environment can affect other organisms and potentially lead to unexpected consequences. (Part 2)

Because events in the natural world are interconnected, any action can have unanticipated side effects.

People both depend on and affect the natural environment.

Summarize how the inquiries of ecologists and environmental scientists differ.

Ecology is a scientific discipline that is related to, but differs from, disciplines such as environmental science.

Public and professional ideas about ecology often differ.

Outline how ecologists use spatial and temporal scales when testing their hypotheses.

Ecology is broad in scope and encompasses studies at many levels of biological organization.

All ecological studies address events on some spatial and temporal scales while ignoring events at other scales.

Compare the advantages and disadvantages of using field observations, field experiments, and lab experiments to test ecological hypotheses. (Part 1)

In an ecological experiment, an investigator alters one or more features of the environment and observes the effect of that change on natural processes.

Compare the advantages and disadvantages of using field observations, field experiments, and lab experiments to test ecological hypotheses. (Part 2)

Some features of the natural world are best investigated with a combination of field observations, experiments, and quantitative models.

Describe the importance of hypotheses, controls, replication, and data analysis to the scientific process.

Experiments are designed and analyzed in consistent ways: typically, each treatment, including the control, is replicated; treatments are assigned at random; and statistical methods are used to analyze the results.

Outline the difference between weather and climate, with specific reference to their temporal scales.

Weather refers to the current conditions of temperature, precipitation, humidity, wind, and cloud cover. Climate is the long-term average and variation in weather at a given location.

Explain the importance of weather variability for ecological processes.

Through their impact on mortality, extreme weather events influence the geographic distributions of organisms.

Summarize how temperature is determined by the gains and losses of energy at Earth's surface. (Part 1)

The climate system is driven by the balance between energy gains from solar radiation and reradiation by the atmosphere.

Summarize how temperature is determined by the gains and losses of energy at Earth's surface. (Part 2)

Energy losses due to infrared radiation from Earth's surface, latent heat flux, and sensible heat flux.

Draw connections between differential heat gain across Earth's surface and the development of atmospheric circulation cells. (Part 1)

Latitudinal differences in the intensity of solar radiation at Earth's surface establish atmospheric circulation cells.

Draw connections between differential heat gain across Earth's surface and the development of atmospheric circulation cells. (Part 2)

The Coriolis effect and the difference in heat capacity between the oceans and the continents act on the Hadley, Ferrell and polar cells to determine the pattern of prevailing winds at Earth's surface.

Explain how surface winds and ocean currents move heat between the tropics and the poles. (Part 1)

Ocean currents are driven by surface winds and by differences in water temperature and salinity.

Explain how surface winds and ocean currents move heat between the tropics and the poles. (Part 2)

Winds and ocean currents transfer energy from the tropics to higher latitudes.

Outline the determinants of global temperature and precipitation patterns. (Part 1)

Global temperature patterns are determined by latitudinal variation in solar radiation, but they are also influenced by oceanic circulation patterns and by the distribution of continents.

Outline the determinants of global temperature and precipitation patterns. (Part 2)

Global patterns of terrestrial precipitation are determined by atmospheric circulation cells, but they are also influenced by semipermanent pressure cells.

Explain how a region's seasonal changes in temperature are affected by its location, whether it is near a large body of water or at the center of a large continent.

Seasonal variation in temperature is greater in the middle of a continent than on the coast because ocean water has a higher heat capacity than land.

Summarize how air density and air exchange cause a decrease in air temperature with increases in elevation on a mountain.

The heating of air by the ground surface is less effective in the highlands because of the lower air density; therefore, temperature decreases as the elevation of the land surface increases.

Describe the changes in an air mass that moves from a maritime zone across mountains, on both the leeward and windward slopes.

Mountains force air masses passing over them to rise and drop most of their moisture as precipitation, resulting in moister environments on windward slopes and drier environments on leeward slopes.

Illustrate how energy exchange components are influenced by vegetation and subsequently affect climate.

Vegetation influences regional climates through its effects on energy exchange associated with albedo, evapotranspiration (latent heat transfer), and surface winds (sensible heat transfer).

Explain how the tilt of Earth's axis influences (1) seasonal changes in air temperature in temperate and polar zones and (2) seasonal changes in precipitation in the tropics.

The tilt of Earth's axis as it orbits the sun causes seasonal temperature changes in temperate and polar regions and precipitation changes in tropical regions.

Outline how seasonal changes in surface heating in temperate and polar lakes influence water density and result in the stratification of water. (Part 1)

Temperature-induced differences in water density result in nonmixing layers of water in oceans and lakes.

Outline how seasonal changes in surface heating in temperate and polar lakes influence water density and result in the stratification of water. (Part 2)

In temperate-zone lakes, these layers break down in fall and spring, allowing the movement of oxygen and nutrients.

Describe how cyclic change in the position and strength of high- and low-pressure cells influences weather and climate variability. (Part 1)

Variations in climate over years to decades are caused by cyclic changes in atmospheric pressure cells.

Describe how cyclic change in the position and strength of high- and low-pressure cells influences weather and climate variability. (Part 2)

The oscillation in the position of high- and low-pressure cells can lead to a weakening of the easterly trade winds or a shift to westerly winds.

Describe how cyclic change in the position and strength of high- and low-pressure cells influences weather and climate variability. (Part 3)

These changes have widespread effects beyond the regions where the pressure cells are located.

Outline what determines the salinity and acidity of soils and waters. (Part 1)

The salinity of Earth's waters, including water in soils, is determined by the balance between inputs of salts and gains (by precipitation) and losses (by evaporation) of water.

Outline what determines the salinity and acidity of soils and waters. (Part 2)

The pH of soils and surface waters is determined by inputs of salts from the breakdown of rock minerals, organic acids from plants, and acidic pollutants.

Explain why oxygen concentrations vary depending on elevation, the influence of water on diffusion, and biological consumption. (Part 1)

Oxygen concentrations are stable in most terrestrial ecosystems, but oxygen availability decreases as elevation increases.

Explain why oxygen concentrations vary depending on elevation, the influence of water on diffusion, and biological consumption. (Part 2)

Concentrations of oxygen in aquatic ecosystems are low where its consumption by organisms exceeds its slow rate of diffusion into water.

Explain why ecologists use plant growth forms to categorize global terrestrial biomes. (Part 1)

Terrestrial biomes are characterized by plant growth forms, particularly of dominant plants.

Explain why ecologists use plant growth forms to categorize global terrestrial biomes. (Part 2)

Plants are immobile, so they must be able to cope with the biome's environmental extremes as well as its biological pressures, such as competition for water, nutrients, and light.

Explain why ecologists use plant growth forms to categorize global terrestrial biomes. (Part 3)

Plant growth forms are therefore good indicators of the physical environment, reflecting climate zones as well as rates of disturbance.

Describe how global patterns of precipitation and temperature, and their variability, influence the location of terrestrial biomes. (Part 1)

Terrestrial biomes reflect global patterns of precipitation and temperature.

Describe how global patterns of precipitation and temperature, and their variability, influence the location of terrestrial biomes. (Part 2)

Temperature influences the distribution of plant growth forms directly through its effect on the physiological functioning of plants.

Describe how global patterns of precipitation and temperature, and their variability, influence the location of terrestrial biomes. (Part 3)

Precipitation influences the availability of water, which is important in determining the supply of nutrients in the soil, which is also an important control on plant growth form.

Evaluate how human activities impact the actual distributions of biomes relative to their potential distributions.

The potential and actual distributions of terrestrial biomes differ because of human activities, particularly conversion of land for agriculture, forestry, and grazing.

List the nine major terrestrial biomes

rainforests, seasonal forests and savannas, and hot deserts in tropical and subtropical zones; grasslands, shrublands and woodlands, deciduous forests, and evergreen forests in the temperate zones; and boreal forests and tundra in polar regions.

Where do biological communities with close analogs to global biomes occur? What are they associated with?

Biological communities with close analogs to global biomes occur in mountains along elevational bands associated with climate gradients.

Summarize how the size of particles on the bottom of streams, as well as water velocity and clarity, change from source streams to large rivers and subsequently influence the organisms that inhabit different zones of moving waters. (Part 1)

Biological communities in streams and rivers vary with stream order and location within the stream channel.

Summarize how the size of particles on the bottom of streams, as well as water velocity and clarity, change from source streams to large rivers and subsequently influence the organisms that inhabit different zones of moving waters. (Part 2)

Coarse terrestrial detritus is most important near the stream source, while the importance of fine organic matter, algae, and rooted and floating aquatic vascular plants increases downstream.

Summarize how the size of particles on the bottom of streams, as well as water velocity and clarity, change from source streams to large rivers and subsequently influence the organisms that inhabit different zones of moving waters. (Part 3)

The general feeding styles of organisms change accordingly as the river flows downstream.

Explain how the depth and amount of light penetration in a pond or lake influence the distribution of photosynthetic and nonphotosynthetic organisms. (Part 1)

Biological communities in lakes vary with depth and light penetration. Photosynthetic plankton are limited to the surface layer of water where there is enough light for photosynthesis.

Explain how the depth and amount of light penetration in a pond or lake influence the distribution of photosynthetic and nonphotosynthetic organisms. (Part 2)

Zooplankton—tiny animals and nonphotosynthetic protists—occur throughout the pelagic zone, feeding on detritus as it falls through the water.

Describe how substrate stability at the bottom of nearshore and shallow ocean zones determines which types of organisms are present, particularly emergent and nonemergent vascular plants and large algae. (Part 1)

Estuaries, salt marshes, and mangrove forests occur in shallow zones at the margins between terrestrial and marine ecosystems. They are influenced by inputs of fresh water and sediments from nearby rivers.

Describe how substrate stability at the bottom of nearshore and shallow ocean zones determines which types of organisms are present, particularly emergent and nonemergent vascular plants and large algae. (Part 2)

Biological communities at the shoreline reflect the influence of tides and the stability of the substrate (sandy vs. rocky).

Describe how substrate stability at the bottom of nearshore and shallow ocean zones determines which types of organisms are present, particularly emergent and nonemergent vascular plants and large algae. (Part 3)

Coral reefs and kelp and seagrass beds are productive communities with high diversity associated with the habitat complexity provided by their photosynthesizers.

Explain how different sources of energy and food affect the type and number of ocean organisms that exist in the water's surface and in the deepest depths.

Biological communities of the open ocean and deep benthic zones contain sparse populations of organisms, whose distributions are determined by light availability and proximity to the bottom.

Explain why the physical environment is the ultimate determinant of the geographic distribution of a species.

The physical environment affects an organism's ability to obtain energy and resources, thereby determining its growth and reproduction and, more immediately, its ability to survive the extremes of that environment.

Differentiate between adaptation and acclimatization by explaining how both individual organisms and populations respond, but differently, to changes in the environment. (Part 1)

Individual organisms can respond to environmental change through acclimatization, a short-term adjustment of the organism's physiology, morphology, or behavior that lessens the effect of the change and minimizes the associated stress.

Differentiate between adaptation and acclimatization by explaining how both individual organisms and populations respond, but differently, to changes in the environment. (Part 2)

A population may respond to unique environmental conditions through natural selection for physiological, morphological, and behavioral traits, known as adaptations, that enhance individuals' survival, growth, and reproduction under those conditions.

Illustrate how adaptation and acclimatization may result in trade-offs with other functions. (Part 1)

Acclimatization and adaptation are not "free"; they require an investment of energy and resources by the organism.

Illustrate how adaptation and acclimatization may result in trade-offs with other functions. (Part 2)

They represent possible trade-offs with other functions of the organism that may also affect its survival and reproduction.

Describe how the body temperature of an organism influences its functioning.

Temperature controls physiological processes through its effects on enzymes and membranes.

Use information about the gains and losses of energy to determine whether an organism's temperature is rising or dropping. (Part 1)

Gains of energy from and losses of energy to the external environment determine an organism's temperature.

Use information about the gains and losses of energy to determine whether an organism's temperature is rising or dropping. (Part 2)

Modifying this exchange of energy with the environment allows an organism to control its temperature.

Identify the heat exchange mechanisms used by plants and animals to regulate their body temperatures. (Part 1)

Terrestrial plants may modify their energy balance by controlling transpiration, increasing or decreasing absorption of solar radiation, or adjusting the effectiveness of convective heat loss.

Identify the heat exchange mechanisms used by plants and animals to regulate their body temperatures. (Part 2)

Animals modify their energy balance mainly through behavior and morphology to adjust heat losses and gains and, in the case of endothermic animals, metabolic heat generation and insulation to lower heat loss.

Contrast ectothermy and endothermy, and explain how each influences the geographic distributions of organisms, along with organisms' sensitivities to changes in body temperature. (Part 1)

Ectothermy is the regulation of body temperature through energy exchange with the external environment, while endothermy is the regulation of body temperature through internal heat generation.

Contrast ectothermy and endothermy, and explain how each influences the geographic distributions of organisms, along with organisms' sensitivities to changes in body temperature. (Part 2)

Generally, ectotherms have a greater tolerance for variation in their body temperature than endotherms.

List the three factors that influence the movement of water from a high-energy state to a low-energy state (i.e., with reference to water potential gradients) in biological systems.

Water flows along energy gradients determined by solute concentration (osmotic potential), pressure or tension (pressure potential), and the attractive force of surfaces (matric potential).

Explain how organisms can control water gains and losses by adjusting resistance to water movement, and describe how high resistance may involve trade-offs with other functions. (Part 1)

Plants and microorganisms can influence water potential by adjusting the solute concentration in their cells (osmotic adjustment).

Explain how organisms can control water gains and losses by adjusting resistance to water movement, and describe how high resistance may involve trade-offs with other functions. (Part 2)

Terrestrial organisms can control their gains or losses of water by adjusting their resistance to water movement, as by the opening or closing of stomates in plants or adaptations of the skin in animals.

Describe how salt and water balances can become challenges for organisms exposed to hyperosmotic and hypoosmotic environments. (Part 1)

Aquatic animals that are hypoosmotic to the surrounding water must expend energy to excrete salts against an osmotic gradient.

Describe how salt and water balances can become challenges for organisms exposed to hyperosmotic and hypoosmotic environments. (Part 2)

On the other hand, aquatic animals that are hyperosmotic to their environment must take up solutes from the environment to compensate for solute losses to the surrounding water.

Differentiate autotrophy from heterotrophy in the context of building energy compounds using external sources of energy versus consuming them from organic matter. (Part 1)

Autotrophs convert energy from sunlight (by photosynthesis) or inorganic chemicals (by chemosynthesis) into energy stored in the carbon-carbon bonds of carbohydrates.

Differentiate autotrophy from heterotrophy in the context of building energy compounds using external sources of energy versus consuming them from organic matter. (Part 2)

Heterotrophs acquire energy by consuming organic compounds from other organisms, living or dead.

Summarize chemosynthesis, which results in the synthesis of energy-rich carbon-carbon bonds.

During chemosynthesis, bacteria and archaea oxidize inorganic substrates to obtain energy, which they use to fix carbon and synthesize sugars.

Outline the steps in the light-driven reactions and carbon reactions of photosynthesis, describing their outcomes and how they produce energy-rich compounds in photoautotrophs.

Photosynthesis has two main steps: the absorption of sunlight by pigments to produce energy in the form of ATP and NADPH (the light-driven reactions) and the use of that energy in the Calvin cycle to fix CO2 and synthesize carbohydrates (the carbon reactions).

Illustrate how photosynthetic organisms acclimatize and adapt to variations in the intensity of light.

Photosynthetic responses to variation in light levels, water availability, and nutrient availability include both short-term acclimatization and long-term adaptation.

Evaluate the trade-offs that result when a plant controls water loss. (Part 1)

Keeping stomates open while tissues lose water can permanently impair physiological processes in the leaf.

Evaluate the trade-offs that result when a plant controls water loss. (Part 2)

Closing stomates, however, not only limits photosynthetic CO2 uptake, but also increases the chances of light damage to the leaf.

Describe how temperature influences photo-synthetic rates through its effect on enzymes and chloroplast membranes. (Part 1)

Autotrophs acclimatize and adapt to temperature variation by changing properties of the Calvin cycle enzymes and/or the photosynthetic membranes.

Describe how temperature influences photo-synthetic rates through its effect on enzymes and chloroplast membranes. (Part 2)

Different photosynthetic organisms have different forms of the same photosynthetic enzymes that operate best under the environmental temperatures where the organisms occur.

Explain the difference between photosynthesis and photorespiration and evaluate conditions where photorespiration is detrimental to plant growth.

Photorespiration operates in opposition to photosynthesis, lowering the rate of energy gain, particularly at high temperatures and low atmospheric CO2 concentrations.

Summarize how biochemical and anatomical adaptations associated with the C4 photosynthetic pathway minimize photorespiration, thereby enhancing photosynthesis rates.

The C4 photosynthetic pathway concentrates CO2 at the site of the Calvin cycle, minimizing photorespiration.

Describe how crassulacean acid metabolism reduces water loss relative to the C3 or C4 photo-synthetic pathways.

CAM plants reduce transpirational water loss by opening their stomates at night to take up CO2 and releasing it to the Calvin cycle during the day, when the stomates are closed.

Illustrate how the chemical makeup of a food item determines the benefit it provides to the consumer eating it.

Variations in the chemistry and availability of food determine how much energy heterotrophs gain from different food sources.

Explain how morphological and behavioral adaptations enable heterotrophs to obtain food more efficiently.

Heterotrophs display tremendous diversity in behavioral, morphological, and physiological adaptations that enhance their efficiency of energy acquisition and assimilation.

Describe how increasing complexity in the digestive systems of heterotrophs makes the assimilation of energy and nutrients more efficient.

Complex digestive systems, such as a tube with an input port and an output port, or additional chambers specializing in specific digestive steps (e.g., stomachs) and absorption (e.g., intestines), make the assimilation of energy and nutrients more efficient.

Summarize the genetic basis for the evolution of traits in organisms.

Biologists often define evolution in a relatively narrow sense as change over time in the frequencies of alleles in a population.

Explain how evolution can be considered the accumulation of trait differences between populations. (Part 1)

Evolution can also be viewed as descent with modification, a process in which populations accumulate differences over time and hence differ from their ancestors.

Explain how evolution can be considered the accumulation of trait differences between populations. (Part 2)

Natural selection modifies populations by favoring individuals with some heritable traits over other individuals.

Explain how evolution can be considered the accumulation of trait differences between populations. (Part 3)

Although natural selection acts on individuals, an individual does not evolve—either it has a favored trait or it does not. Only populations evolve.

Summarize how mutations contribute to the process of evolution.

Mutation and recombination are the sources of new alleles and new combinations of alleles, thereby providing the genetic variation on which evolution depends.

Compare the effects of stabilizing selection and disruptive selection on the temporal changes in the genetic structure of a population. (Part 1)

Natural selection occurs when individuals with certain heritable phenotypic traits survive and reproduce more successfully than individuals with other traits.

Compare the effects of stabilizing selection and disruptive selection on the temporal changes in the genetic structure of a population. (Part 2)

Natural selection may favor the average traits (stabilizing selection) or traits near the extremes in a population (disruptive selection).

Evaluate how random events can affect populations through time via genetic drift.

Genetic drift, which occurs when random events determine which alleles are passed from one generation to the next, can have negative effects on small populations.

Describe the role of gene flow among populations in terms of homogenizing genetic structure as well as enhancing evolutionary change.

Gene flow, the transfer of alleles between populations, makes populations more genetically similar to one another and can introduce new alleles into populations, enhancing evolutionary change.

Explain how natural selection can lead to adaptations in populations. (Part 1)

By favoring individuals that have advantageous alleles over individuals that have other alleles, natural selection can cause adaptive evolution, in which the frequency of an advantageous trait in a population increases over time.

Explain how natural selection can lead to adaptations in populations. (Part 2)

Natural selection can increase the frequency of advantageous traits rapidly—in days to years, depending on the organism and the selection pressure.

Evaluate the conditions in which gene flow can promote or deter adaptations. (Part 1)

Gene flow can promote the extent to which a population is adapted to its local environment by introducing new alleles into a population.

Evaluate the conditions in which gene flow can promote or deter adaptations. (Part 2)

Gene flow can also limit the extent to which a population is adapted to its local environment by preventing fixation of the favored allele.

Describe factors that limit the development of adaptations in populations.

Constraints on adaptive evolution result from factors such as lack of genetic variation, evolutionary history, and ecological trade-offs.

Describe the process by which isolation of populations can lead to speciation. (Part 1)

The genetic divergence of populations over time can lead to speciation, the process by which one species splits into two or more species.

Describe the process by which isolation of populations can lead to speciation. (Part 2)

Speciation requires the evolution of reproductive barriers between populations.

Evaluate the roles of speciation and extinction in determining the diversity of species. (Part 1)

The number of species in a group of organisms increases when more species are produced by speciation than are lost to extinction, and decreases when the reverse is true.

Evaluate the roles of speciation and extinction in determining the diversity of species. (Part 2)

The outcome of this process can be visualized with an evolutionary tree.

Explain how mass extinctions and rapid adaptations have influenced long-term patterns in diversity. (Part 1)

Biological communities can lose much of their diversity in mass extinctions, global events in which large proportions of Earth's species are driven to extinction in a relatively short time.