Ecology Study Guide for Exam Part 1

Ecology Exam 1 Introduction - Nature of Ecology Vocabulary Ecology: The study of relations between organisms and their natural environment, living and nonliving. ! Population: A group of individuals of the same species living in a given areas at a given time. Community: A group of interacting plants and animals inhabiting a given area. Ecosystem: The biotic community and its abiotic environment, functioning as a system. Landscape: An area of land (or water) composed of a patchwork of communities and ecosystems. Biome: Major regional ecological community of plants and animals; usually corresponds to plant ecologistsÕ and European ecologistsÕ classification of plant formations and life zones. Biotic: Applied to the living component of an ecosystem. Abiotic: Nonliving; the abiotic component of the environment includes soil, water, air, light, nutrients, and the like. Biosphere: Thin layer about earth in which all living organisms exist. Hypothesis: Proposed explanation for a phenomenon; we should be able to test it, accepting or rejecting it based on experimentation. Model: In theoretical and systems ecology, an abstraction or simplification of a natural phenomenon, developed to predict a new phenomenon or to provide insight into existing ones; in mimetic association, the organism mimicked by a different organism. Independent Variable: The variable that is changed or controlled in a scientific experiment to test its effects on the dependent variable. ! Dependent/Response Variable: The variable that is being tested and measured in a scientific experiment. ! Learning Objectives Introduction Summary Sensing the world from an organismÕs point of view *The individual is the basic unit in Ecology It senses and responds to the prevailing physical environment. The collective properties of individual births and deaths drive the dynamics of populations, and individuals of different species interact with one another in the context of the community. Most importantly, the individual, through the process of reproduction, passes genetic information to successive individuals, defining the nature of individuals that will compose future populations, communities, and ecosystems. At the individual level we can begin to understand the mechanisms that give rise to the diversity of life and ecosystems on Earth - mechanisms which are governed by natural selection. Ecological Levels of Organization/Hierarchy Individual Population Community Ecosystem Landscape Biome Biosphere Scientific Method Observations Question Hypothesis Predictions Hypothesis Testing ! Earth Systems & Climate Vocabulary Earth System: Refers to EarthÕs interacting physical, chemical, and biological processes. Consists of the land, oceans, atmospheres, and poles to include the planetÕs natural cycles and deep Earth processes. Also includes human society which are now the main drivers of changes in the Earth systems. Open System: Both energy and matter can cross its boundary. Earth for example. Closed System: Only energy can cross its boundary. Hydrosphere: All the waters on the EarthÕs surface such as lakes and seas, and sometimes including water over the earthÕs surface, such as clouds. Atmosphere: The envelope of gases surrounding the Earth or another planet. Lithosphere: The rigid outer part of the Earth, consisting of the crust and upper mantle. All rocks on earth. Biosphere: Thin layer about Earth in which all living organisms exist. Includes the living organisms as well as the physical environment capable of supporting life. Biodiversity: The variety of life in the world or in a particular habitat or ecosystem. The species richness/ number of species in a given area. Gaia Hypothesis: -The biosphere and physical components of earth work together to form an interacting system that maintains the climatic and biogeochemical conditions on Earth in a preferred homeostasis. -Theory proposed by James Lovelock that living matter on the earth collectively defines and regulates the material conditions necessary for the continuance of life. The biosphere is likened to a vast self-regulating organism. -Proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps maintain and perpetuate the conditions for life on the planet. ! Solar Constant:! Rate at which solar energy/radiation is received on a surface just outside the EarthÕs atmosphere. The solar gradients are what drive the physical and biological world. Solar radiation is absorbed and converted into metabolic energy in the EarthÕs vegetation. Weather: The combination of temperature, humidity, precipitation, wind, cloudiness, and other atmospheric conditions at a specific place and time. ! Climate: Long-term average pattern of local, regional, or global weather. ! Electromagnetic Spectrum: The range or wavelengths or frequencies over which electromagnetic radiation extends. Each wave within each band have different characteristics, such as how they are produced, how they interact with matter and their practical applications in the world. ! Visible Light: Frequency of electromagnetic radiation which can be perceived/detected by the eye. ! Photosynthetically Active Radiation (PAR): Portion of the light spectrum that is used by plants for photosynthesis. Between 400-700 wavelengths. Greenhouse Gas: A gas that absorbs long wave radiation and thus contributes to the greenhouse effect which present in the atmosphere; includes water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Greenhouse Effect: Selective energy absorption by carbon dioxide in the atmosphere, which allows short wavelength energy to pass through but absorbs longer wavelengths and reflects heat back to the Earth. Coriolis Effect: Physical consequence of the law of conservation of angular momentum; as a result of EarthÕs rotation, a moving object veers to the right in the Northern Hemisphere and to the left in the Southern Hemisphere relative to EarthÕs surface. Gyres: Circular motion of water in major ocean basins. ! Intertropical Convergence Zone (ITCZ): The boundary zone separating the northeast trade winds of the Northern Hemisphere from the southeast tradewinds of the Southern Hemisphere. Hadley Cell: Large scale atmospheric convection cell in which air rises at the equator and sinks at medium latitudes, typically about 30 degrees north or south. Responsible for the trade winds in the Tropics and control low altitude weather patterns. The differential heating and cooling of the earth results from these air masses and their movement. Tropic of Cancer: Most northernly portion of earth in which the sun can be directly overhead. 30 degrees north of equator. Tropic of Capricorn: Most southernly portion of earth in which the sun can be directly overhead. 30 degrees south of equator. Tropical: The portion of the earth located within Cancer and Capricorn. Generally most warm and humid climate on Earth. ! Microclimate: Climate on a very local scale, which differs from the general climate of the area; influences the presence and distribution of organisms. Solstice: Either of the two times during the year, summer or winter, when the sun reaches its highest or lowest point in the sky at noon, marked by the longest and shortest days. Equinox: The time or date twice a year at which the sun crosses the equator, when day and night are of equal length. ! Relative Humidity: The amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature. It is a function of moisture content and temperature. ! Albedo: Ratio of light reflected back off the planet compared to the total amount of light which is received by the planet. ! Learning Objectives Identify elements of the Earth System Atmosphere/Air Hydrosphere/Water Lithosphere/Land Biosphere/Life ! Describe interactions of the Earth System elements and their role in generating climate Atmosphere: Prevents the sudden increase/decrease in temperature during the daylight and nighttime hours. Regulates the retention and escape of heat from earth to outer space. It maintains an average temperature/climate over time. Hydrosphere: The oceans absorb huge amounts of solar energy and its currents transport the heat from the equator to the poles to maintain the climates. Water is transported throughout the Earth via precipitation and water vapor. Lithosphere: Land absorbs solar energy and is used to heat the environment. Altitude determines climate due to the fact higher elevations have air that is cooler and expands and lower elevations have more dense warm air. Land masses also affect the type of precipitation. Internal factors such as volcanos are responsible for emitting hot gases into the oceans and atmosphere which contributes to the temperature. Biosphere: Plants reduce the amount of CO2 in the atmosphere. Animals and humans add to the greenhouse gases in the atmosphere. Humans have significantly impacted the other elements due to overconsumption and development of greenhouse gases. It has disrupted the natural ecosystemÕs ability to self-regulate. Distinguish between climate and weather Weather is a short term description of the combination of the temperature, humidity, precipitation, wind, cloudiness and other atmospheric conditions at a certain place and time. Climate is the long term, average weather pattern present in an area whether it be local, regional or global. Identify the cause of seasonal changes The earth tilts on its axis while orbiting the sun. The tilt, referred to as inclination, will be either toward or away from the sun and determines the change in the seasons. Those regions tilted toward the sun experience summer, tilted away experience winter, etc. Variation in solar radiation input affects global difference in temperatures. Explain mechanisms of variation in major climatic factors (e.g. solar radiation, temperature, precipitation) Solar Radiation: Variation in the amount of solar radiation reaching the earth is caused by the sun and earthÕs cycles. The degree of these effects and variations depends on the current state of ! the Earth i.e. amount of greenhouse gases, biosphere conditions, etc. The EarthÕs tilt and orbit; the sunÕs natural up and down 11-year cycle and its overall output. The idea is these affect the intensity of radiation received on earth. Reflectivity and albedo (amount of solar radiation reflected from an object) of the earth. Temperature: Variation is caused by the change in how much and what type of solar radiation reaches Earth, changes in the reflectivity of the earthÕs atmosphere and surface, and changes in the greenhouse effect which affects the amount of heat retained by EarthÕs atmosphere. Precipitation: Rising temperatures causes EarthÕs water cycles to intensify and increases evaporation; increased evaporation contributes to more precipitation and drying of some land masses. More moisture in the air causes more rain and humidity and different weather patterns and changes in overall climate. Explain the Gaia Hypothesis The idea that all living things on earth (biosphere) function as a single super organism that changes its environment to create conditions that best meet its needs with the ability to selfregulate critical systems necessary in sustaining life. Describe El Nino Southern Oscillation events and predict their effect on local climate An irregularly periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean. Warming phase - El Nino; Cooling phase - La Nina. Southern Oscillation is the accompanying atmospheric component coupled with the sea temperature change. El Nino - high air surface pressure; La Nina - Low air surface pressure (in tropical western Pacific). ! They produce a higher than usual rate of precipitation in our local climate during the wintertime. ! Niche, Conditions, and Resources Vocabulary Conditions: An abiotic environmental factor that influences the function of a living organism. Conditions maybe altered by another organism but not consumed by another organism (i.e. temperature, humidity, soil pH maybe altered under a forest canopy). ! Examples: Temperature, humidity, pH levels, salinity levels, pollutants, physical forcing of wind, wave and currents Temperature as a Condition: Most important condition which affects organisms. Metabolism tends to increase with temperature due to increased speed of molecular movement. The distributions of many plants and animals are correlated with an aspect of environmental temperature. The occasional extremes are important in determining a species range as it shows where they cannot survive. Some are suited/thrive in the more extreme temperatures i.e. desert/arctic. (extreme being relative to the organism) Q10 Rule: For each 10 degrees celsius increase, the rate of biological enzymatic processes roughly doubles. Heat Exchange Pathways: Manner in which heat is accumulated in the environment and transferred to the organism. Conduction: Direct transfer of heat energy from one substance to another. Convection: Transfer of heat by the circulation of a liquid or gas. Radiation: Transfer of heat through empty space. Optimum Conditions: Conditions under which individuals leave most descendants (are the fittest) due to being able to survive and thrive and reproduce. Impossible to measure at a specific time due to the fact it measurements are taken over time over several generations. Instead more often measure the effect of conditions on some key property like the activity of an enzyme, the respiration rate of a tissue, the growth rate of individuals or their rate of reproduction. ! *Organisms can usually survive over a wider range of conditions than permit them to grow or reproduce! ! Environmental Condition Effects in a Niche Response Curves Optimum Response curves illustrating the effects of environmental conditions on individual survival (S), growth (G), and reproduction (R). ! Graph A: Shows extreme conditions (i.e. extreme cold/extreme heat) are lethal; less extreme conditions allow survival but prevent growth; only optimal conditions allow survival, growth and reproduction. Graph B: Show the condition is only lethal when present at high intensities/ concentrations. For example most toxins, radioactive emissions, and chemical pollutants have no effect at low level concentrations but as the concentrations increase, their effects increase and take a toll first on reproductive success, then growth and finally on survival. Graph C: Shows that the condition is required by the organism, as a resource, at low concentrations but is lethal if the concentration increases. For example minerals are essential to growth but become lethal if presented to the organism in higher than normal concentrations such as by pollutants. ! Resources: All things consumed by the organism. Examples: Radiation/Sun, carbon dioxide, oxygen, water, minerals, mates, prey, shelter/ space/habitat Energy and Carbon as Resources: Living cells require both an energy source and a source of carbon to build necessary components for all cell structures. ! Energy is acquired from one of two sources. Phototroph: Gathers light energy from the sun using chlorophyll. Chemotroph: Gets energy through the breakdown of molecules. Chemoorganotroph: Use organic compounds like sugar. Chemolithotroph: Use inorganic compounds like minerals. ! Carbon can come from one of two sources; from the air or from the breakdown of organic molecules. Heterotroph: Gets organic carbon from the breakdown of other organic matter. Autotroph: Takes CO2 from the air, keeps the carbon and releases the oxygen. Distinguish between conditions and resources Conditions are all of the abiotic/non-living (soil, water, air, light, nutrients) that influence the function of the organism which can be affected by another organism but not consumed. Resources are the factors which influence the function of the organism that are consumable. Conditions = Abiotic Factors; competition not possible. Resources = Consumable Factors; competition is possible. ! Classification of Resources ! and the Ecological Niche: Isocline A = Negative Growth Rate ! Isocline B = Zero Growth Rate ! Isocline C = Positive Growth Rate Resource Dependent Growth Isocline: Each of the growth isoclines (lines) represents the amounts of two resources (R1 & R2) that would have to exist in a habitat for a population to have a given growth rate. Because the growth rate increases with resource availability, isoclines further from the origin represent higher population growth rates. Zero Net Growth Isocline: Shows all of the combinations of the two resources where there is zero growth due to each of the resource levels available;organism can maintain itself, not die, not thrive. Defines a boundary of a speciesÕ ecological niche. ! Classification of Resources: Essential Resource: Two resources are said to be essential when neither can substitute for the other. For example air and food. Substitutable: Two resources which can wholly replace one another without implying that one resource is better than another. For example zebra and gazelle can be interchanged to a lion. Complementary: Two substitutable resources that when consumed together the organism requires less of. For example beans and rice. Beans are rich in lysine/poor in S amino acids; rice is poor in lysine/rich in S amino acids. More of one is needed to compensate. If both are consumed, the organism can eat less to meet the necessary requirement for lysine/S amino acids. Antagonistic: Two substitutable resources that when consumed together the organism will need more of the resources than when consumed separately. For example eating one resource doesnÕt affect the growth of a larva but when they eat both resources its growth is significantly less. Inhibition: Shows a pair of essential resources but which become damaging when in excess. For example CO2, water and minerals are all required for photosynthesis but each is lethal in excess. It is closed curves because growth decreases with an increase in resources at very high levels. ! Niche Concept: A framework for understanding the relationship between an individual and its resources and condition. Ecological Niche: The range of physical and chemical conditions under which a species can persist (survive and reproduce) and the array of essential resources it utilizes. A summary of the organismÕs tolerances and requirements. ! HutchinsonÕs Definition: The ways in which tolerances and requirements interact to define the conditions and resources needed by an individual or a species in order to practice its way of life. The real niche of a species is multidimensional as it is a collection of the ranges of tolerance for different conditions/resources. All variables relevant to the life of the organism must be included and must be independent of one another. Each component has its own tolerance range. ! ! ÒN-dimensional HypervolumeÓ: where n is the number of conditions that make up the ecological niche of an organism represented each by a different axis on a graph. **The simplified three-dimensional version captures the idea of an ecological niche of a species. It is a concept defined by the boundaries that limit where it can live, grow and reproduce. Difference between Habitat and Ecological Niche: Ecological Niche ≠ Habitat ! Niche turns out the be an abstract or conceptual space; its an idea. Habitat is the space where the organism actually lives; physical place. -Generally, the space must meet the niche requirements of the organism for it to flourish. -A niche includes the habitat in addition to other factors. Fundamental Niche: All possible places an organism could exist defined by the sum of the tolerances and requirements of that organism/species. Realized Niche: The portion of the fundamental niche that a species actually exploits as a result of interactions with other species. -more limited spectrum of conditions and resources tat allow it to persist, even in the presence of competitors and predators. ! ! *Usually the fundamental niche is larger than the realize niche due to presence of predators or competitors that prevent the full niche space from being used. ! Anoxia: The absence of oxygen. ! Hypoxia: A deficiency of the amount of oxygen in a biotic environment. ! **Purpose of understanding that the individual is the basic unit of ecology: to understand that the study of ecology revolves around:! 1.) What comprises the environment of the individual ! 2.) Consider the factors that influence the individualÕs survival, growth, and reproduction ! 3.) Determine its overall fitness relative to these factors Learning Objectives Use response curves and the niche concept to describe how conditions and resources affect individuals ! (See page 9 & 11 of study guide)! Condition and Niche are shown by the bell curve graphs with the reproduction, growth and survival taken into account. Resource and Niche are shown by the isoclines which show that different resources effect each other and the organism differently. Explain how conditions and resources influence the distribution and abundance of organisms (provide examples) Both of these influence where an organism can live. If the conditions and resources are optimal, there will likely be a larger population. If the conditions are extreme and resources scarce, there will likely be little to no population. Optimum resources and conditions will allow organisms to thrive and follow the locations of where these optimum resources and conditions are. Discuss why temperature is an important condition ! Metabolism tends to increase with temperature due to increased speed of molecular movement. The distributions of many plants and animals are correlated with an aspect of environmental temperature. The occasional extremes are important in determining a species range as it shows where they cannot survive. Some are suited/thrive in the more extreme temperatures i.e. desert/ arctic, (extreme being relative to the organism), whereas some cannot handle the effects. ! Explain why it is not always sufficient to know the average condition or resources. (provide examples) Some ecosystems experience occasional extremes which are important to determining the range of where the organism can survive. For example the Saguaro cactus can survive a freeze of less than zero degrees for up to 36 hours but will likely die after that time frame. Its an important factor in plant distribution. It shows the line between tolerating and not liking the condition/ resource at hand and absolutely not being able to stand it. ! Classify organisms based on their energy and carbon sources Energy is acquired from one of two sources. Phototroph: Gathers light energy from the sun using chlorophyll. Chemotroph: Gets energy through the breakdown of molecules. Chemoorganotroph: Use organic compounds like sugar. Chemolithotroph: Use inorganic compounds like minerals. ! Carbon can come from one of two sources; from the air or from the breakdown of organic molecules. Heterotroph: Gets organic carbon from the breakdown of other organic matter. Autotroph: Takes CO2 from the air, keeps the carbon and releases the oxygen. Use your understanding of conditions to explain the potential impacts of global climate change Relocation/reduction of where organisms are able to populate which can lead to extinction of some organisms and the need for some organisms to find new food resources which could affect the population of another organism by taking away from their supply. !