Introduction to Ecology PDF

Introduction To\ Ecology\ \ What is Ecology?\ The Nature of Ecology\ \ What is Ecology?\ Ecology is the Scientific study of\ the relationship of organisms to one\ another & to the abiotic components\ of their environment\ The Nature of Ecology Ecology is an interdisciplinary\ science\ -- in...

Introduction To\ Ecology\ \ What is Ecology?\ The Nature of Ecology\ \ What is Ecology?\ Ecology is the Scientific study of\ the relationship of organisms to one\ another & to the abiotic components\ of their environment\ The Nature of Ecology Ecology is an interdisciplinary\ science\ -- involves often complex interactions\ within natural systems\ The Nature of Ecology\ \ -- Life's scale\ ranges from\ Cellular to Global\ Biologists Can Study Life At\ Many Different Levels\ \ Biologists Can Study Life At Many\ Different Levels Atom\ Molecule\ Organelle\ Cell\ Tissue\ Organ\ Organ System\ Organism\ Population\ Community\ Ecosystem\ Biosphere \... BUT\...\ \ \ ECOLOGISTS Only Study Life At These\ Levels: Atom\ Molecule\ Organelle\ Cell\ Tissue\ Organ\ Organ System\ Organism\ Population\ Community\ Ecosystem\ Biosphere\ \ The Individual Organism\ forms the basic unit in Ecology\ -- The individual senses and\ responds to the prevailing\ physical environment\ -- It is through the individual that\ genetic information is passed\ along\ The Nature of Ecology A Population is a group of individuals\ of the same species that occupy a\ given area\ The Nature of Ecology\ \ A Community\ includes all\ Populations of\ all species\ interacting within\ an ecosystem\ The Nature of Ecology\ \ An Ecosystem is the\ environment in which\ organisms carry out\ their \"struggle for\ existence\"\ -- Includes an\ environment\'s physical\ conditions & the array of\ biological organisms\ within its boundaries\ The Nature of Ecology The Landscape is a larger\ area of land or water that is\ composed of different\ Communities and\ Ecosystems\ -- At this level, Communities\ and Ecosystems are linked\ by the dispersal of organisms\ and the exchange of\ materials\ The Nature of Ecology\ \ Biomes are geographic regions\ with similar geological and\ climatic conditions\ -- Tropical rain forest\ -- Desert\ -- Grasslands\ The Nature of Ecology\ Major Biomes of North America\ \ The\ Biosphere is\ the thin layer\ surrounding\ the Earth that\ supports all of\ life\ The Nature of Ecology Organisms interact with other organisms\ on many different levels\ -- Individual (organism to organism)\ -- Population\ -- Community\ -- Ecosystem\ -- Landscape\ -- Biome\ -- Biosphere\ The Nature of Ecology\ \ Populations within an ecosystem\ can interact with one another:\ --By competing for resources\ --As predator--prey\ --In mutually beneficial relationships\ The Nature of Ecology\ \ Organisms interact with their physical\ environment at many levels\ -- Physical and chemical conditions influence an\ organism\'s physiology\ Temperature\ Light\ Oxygen\ Carbon dioxide\ The Nature of Ecology Ecologists ask different questions and\ are interested in different patterns at\ different ecological levels. E.g\.....:\ -- Individual: birth and death events\ -- Population: rates of birth and death,\ distribution of individuals\ -- Community: factors that influence the relative\ abundance of a species\ -- Ecosystem: flow of energy and nutrients\ through the physical and biological systems\ The Nature of Ecology\ \ Ecology is a Science!\ Science is a continuous process of\ testing and correcting concepts\ -- The exploration of concepts is limited to\ the facts (i.e. "evidence")\ -- Scientific concepts have no guaranteed\ permanence\ -- Science is a search for evidence that\ proves our concepts wrong!!!\ The Nature of Ecology\ -- Science\ Latin verb "to know"\ Is a way of gathering\ information, of\ "knowing"\ Science -- Science\ Is based on Evidence\ Is Verifiable ("Repeatable")\ Science\ ▪ Science - the branch of study involved\ with the systematic\...\ - Observation\ - Recording\ - Organization\ - Classification\...\ \... of facts from which natural laws are\ derived & used predictively.\ Science\ Question: Which system is used to\ conduct Scientific Investigations?\ Answer: the Scientific\ Method!\ Science Scientific Method\ Scientific Method\ My houseplant has wilted!\ Scientific Method\ Why did it wilt?\ My houseplant has wilted! Hypothesis:\ is a\ proposed\ explanation\ Hypothesis\ Must be testable! E.g.:\ --"My plant wilted because the soil\ is dry" is testable.\ --"My plant wilted because it hates\ me" is not testable because we\ can't measure/observe hatred in\ plants.\ Hypothesis\ Must be falsifiable! E.g.:\ "My plant wilted because the\ soil is dry" is falsifiable;\ "My plant wilted because the\ soil might or might not be dry" is\ not falsifiable The Aquatic\ Environment:\ Freshwater &\ Marine Systems\ Chapter 5 The Aquatic Environment\ Water is the essential substance of life\ -- 75 to 95 percent of the weight of all living\ cells is water\ -- \~ 70 percent of each living organism is water\ Chapter 5 The Aquatic Environment\ Water\ -- covers 75 percent of\ the planet\'s surface;\ is the dominant\ environment on\ Earth\ Saltwater (marine)\ Freshwater -- only\ 3% Hydrologic Cycle:\ -- process by which water travels in a sequence\ from the air to Earth & returns to the\ atmosphere\ -- Solar Radiation is the driving force\ provides energy for the evaporation of water\ Chapter 5 The Aquatic Environment\ Water vapor in the atmosphere eventually\ falls in some form of Precipitation\ Chapter 5 The Aquatic Environment\ Interception\ occurs when\ precipitation falls\ onto vegetation,\ dead organic\ matter, exposed\ bedrock & urban\ structures or\ streets\ -- Evaporates\ directly back to the\ atmosphere\ Chapter 5 The Aquatic Environment As rain falls on the\ soil surface, it\ moves into the soil\ by Infiltration\ Chapter 5 The Aquatic Environment\ Surface Runoff of this water occurs when\ the soil is saturated\ Chapter 5 The Aquatic Environment\ The water that seeps down to an\ impervious layer of rock collects as\ Groundwater\ Chapter 5 The Aquatic Environment Evapotranspiration -\ total amount of water\ evaporating into the air\ -- Surficial water in terrestrial\ and aquatic environments\ returns to the atmosphere\ by Evaporation\ -- Transpiration is the\ evaporation of water from\ the internal surfaces of\ plants\ Chapter 5 The Aquatic Environment\ Water Has Important Physical Properties:\ Chapter 5 The Aquatic Environment\ -- Temperature Stability\ -- water must absorb\ (or lose) great\ quantities of heat to\ change its temperature\ Helps to buffer aquatic\ habitats\ Is important for\ Thermal Regulation\ within living organisms\ Water Has Important Physical Properties (con't):\ -- Solid water (Ice) is less dense than liquid water\ In Ice:\ -- The chemical bonds between molecules are more stable\ -- The molecules are more widely spaced than in liquid water\ Therefore, ice floats on liquid water\ -- This allows for insulation of water bodies so that they do not\ freeze solid\ Chapter 5 The Aquatic Environment Water Has Important Physical Properties\ (con't):\ -- Cohesion is the attraction among water molecules\ with each other due to hydrogen bonding\ -- Adhesion is the attraction between water molecules\ and other substances\ Chapter 5 The Aquatic Environment\ Water Has Important Physical Properties\ (con't):\ -- Surface Tension of water is the result of the\ greater attraction of water molecules with each\ other (Cohesion) than between water & the\ molecules in air (Adhesion)\ Chapter 5 The Aquatic Environment\ Viscosity is the property that\ measures the force necessary to\ separate the molecules of a liquid.\ For water it is related to Cohesion\ Chapter 5 The Aquatic Environment Water has a High Viscosity\ due largely to its greater\ density (860x that of air!)\ -- Aquatic organisms\ experience Buoyancy in\ water because of the\ upward force of water\ acting on the less dense\ object\ Chapter 5 The Aquatic Environment\ Aquatic organisms must cope\ with the Frictional Resistance\ of water & overcome Viscosity\ -- The Frictional Resistance of\ water is 100x greater than air!\ Chapter 5 The Aquatic Environment\ Light & Water:\ -- Some of the light that strikes the\ surface of water is reflected\ is related to the angle of light\ -- As light enters the water surface, it\ is absorbed or scattered by\ suspended particles and water\ Chapter 5 The Aquatic Environment Light & Water (con't):\ -- Water absorbs some\ wavelengths of visible\ light more than others:\ Longer wavelengths (red\ light) are absorbed first\ Blue wavelengths alone\ penetrate the depths\ Chapter 5 The Aquatic Environment\ The pattern of light absorption in\ water gives rise to unique adaptations\ in aquatic organisms\ -- Body color or lack of pigmentation\ -- Large eyes\ -- Bioluminescence\ Chapter 5 The Aquatic Environment\ Light & Water (con't):\ © 2012 Pearson Education, Inc.\ Surface water Temperature increases as sunlight is\ absorbed:\ -- Heat is then distributed vertically as winds and surface\ waves mix\ -- The decrease in water temperature with increasing depth\ does not follow the same pattern as light attenuation\ Chapter 5 The Aquatic Environment Epilimnion: warm, lighter water at or near\ surface\ Hypolimnion: "deep water"; cold, denser water\ Thermocline (aka Metalimnion): region of the\ vertical depth profile located between the\ Epilimnion & Hypolimnion\ -- Temperature declines most rapidly here\ Chapter 5 The Aquatic Environment\ Thermocline (aka Metalimnion) :\ -- Depth depends on solar radiation input & level of mixing\ -- Thermocline depth is permanent in Tropical Waters\ -- Temperate Waters often experience a mixing of the\ Epilimnion & Hypolimnion in the fall & spring\ Chapter 5 The Aquatic Environment\ The temperature profile of a flowing body of\ water is highly variable, however\ Chapter 5 The Aquatic Environment A solution is a liquid with a homogeneous\ mixture of 2 or more substances\ -- The solvent is the dissolving agent\ -- The solute is the substance dissolved\ -- An aqueous solution has water as the solvent\ Water can dissolve more substances than\ any other liquid. This is crucial to biological\ systems!\ Chapter 5 The Aquatic Environment\ Atmospheric water is nearly\ pure (it has no dissolved\ ions)\ -- As water precipitates & then\ passes over a substrate, it\ dissolves & acquires\ numerous solutes\ -- Freshwaters have a much\ lower concentration of\ solutes (ions) than\ Saltwater bodies\ Chapter 5 The Aquatic Environment\ Maximum Solubility: water can only dissolve &\ retain a certain level of solutes ("Saturation")\ -- once this is reached, additional solutes will precipitate\ from the water\ Chapter 5 The Aquatic Environment The solubility of Sodium Chloride (NaCl) is very\ high and accounts for most of the solutes (ions\ or salts) in seawater\ Salinity is determined by an index of Chlorine\ (the most abundant element in seawater)\ Salinity is expressed as a percentage\ -- Freshwater = 0.065 ‰ to 0.30 ‰\ -- Open Sea = 35 ‰\ Chapter 5 The Aquatic Environment\ Chapter 5 The Aquatic Environment\ Oxygen diffuses from the atmosphere ("air") into\ the surface waters of aquatic environments\ -- Then diffuses from the surface waters to deeper waters\ -- However, may become stratified in lakes & ponds\ during the summer\ Warm water holds less oxygen\ Both the atmosphere & aquatic plants are oxygen sources\ Winds mix oxygen-rich water with oxygen-poor water\ Maximum oxygen levels in oceans\ are found in the upper 10 to 20\ meters\ The oxygen content of flowing water\ is high due to the greater contact of\ water with the atmosphere\ Chapter 5 The Aquatic Environment