EVS 104 Exam 1
Freshwater Ecosystems
o Occupy 2% of the earth's surface, play important role in hydrologic cycle o Standing-water, lakes and ponds have 3 zones: littoral, limnetic, profundal o Zonation accentuates thermal stratification, temperature changes with depth o Undergoes spring turnovers of water from different layers mixing o Human effects: eutrophication, unnatural nutrient enrichment
Threatened Oceans
o Oceans cover 2/3 of the Earth's surface, home to half the world's biodiversity o Over 70% of the world's commercial fish species are depleted/nearing depletion o 50% of coral reefs worldwide are threatened by human activity o caused by many factors: overfishing, pollution, increased CO2 emissions, global climate change, coastal development
Darwin's Finches
o On the Galapagos Islands off coast of Ecuador - Darwin studied plants and animals on each island - 14 species of finches o Conclusion: finches had common mainland ancestor but had become geographically isolated and adapted to different diets
Resource Partitioning
o One way species avoid or reduce niche overlap o Serves to reduce competition for resources o Can include timing of feeding, nest sites, location of feeding
Sustainable Food Production and Environmental Tradeoff
o Optimists: suggest decrease in b will stabilize human population o Others predict widespread environmental degradation - large areas of rainforest are being cleared for cattle ranching o The more highly developed countries become the lower K
Interactions Among Organisms - Symbiosis
o Organisms of an ecosystem interact and form associations o Symbiosis: 2 species living in close association - result of coevolution o 3 main types of symbiosis: mutualism, commensalism, parasitism
Results of Environmental Exploitation
o Overpopulation o Increasing need for food and portable water o Increased need for waste management o Increased reliance on non-renewable energy and raw materials.
Ozone Depletion and Polar Ice Cap
o Polar ice cap melting at accelerated rate o "Ozone Hole" over Antarctic continues to thin - CFC ban, stratospheric ozone protects Earth from UV radiation, increase in skin cancer and ocular issues
Population Ecology
o Population: individuals of a particular species living in a defined area o Branch of biology that studies individuals in a defined area o Concerned with how and why population increases/decreases over time as a result of competition, disease, and predation
Population Crash
o Populations rarely stabilize at K - instead temporarily rise above and drop below, hovering around K o Some populations that overshoot K can crash - abrupt decline from high to low population density as resources are exhausted
IPAT
o Developing nations have lower individual footprints, but because of their large populations, their overall footprint is high o I = P x A x T o Impact = # of People x Affluence/resources consumed x technology used to obtain and consume resources o Goal: sustainable consumption
Succession
o Ecological succession: the process of community development over time through sequence of species o Resident species modify the environment - make it more suitable for later species o Former concept of stable "climax community" - replaced with reality that communities continue to change o Primary/secondary succession: have specific species compositions
The First Law of Thermodynamics
o Energy cannot be created or destroyed o Total energy content is always the same o Energy can change from one form to another - in photosynthesis, solar energy is converted to chemical energy
Goals of Environmental Science
o Establish general principles about how the natural world functions o Identifying, understanding, solving problems that we have created o Focus on solving problems based on scientific knowledge
The Phosphorous Cycle
o No atmospheric component o Cycles between land and organisms o Phosphorous in soil is absorbed by plant roots - necessary to make nucleic acids and ATP o Anthropogenic loss of terrestrial phosphorus o Phosphorus in fertilizers can cause eutrophication like in Lake Washington
Nonrenewable Resources vs. Renewable Resources
o Nonrenewable resources: fossil fuels - finite supply that took millions of years to form o Renewable resources: trees, soil, water - potentially replaced by natural processes
Overpopulation
o 2011: human population exceeded 7 billion, several billion more projected in the 21st century o 1 in 4 people lives in poverty o Fertility rates: 1.7 in highly developed countries, 4.5 in least developed countries o Gap between the rich and the poor - 18% of the world's population lives in highly developed countries, 82% live in poor/moderately developed countries
Food Web
o A complex of interconnected food chains in an ecosystem o Gives a more realistic view of the linear flow of energy in an ecosystem than is shown in a food chain
Exponential Population Growth
o Accelerated population growth occurs when optimal conditions allow a population to reproduce at a constant rate o J-shaped growth curve o Larger a population gets - faster it grows
Communities
o All the populations of different species that live and interact together within an area at the same time
Energy Consumers
o Animals that consume other organisms o Primary consumers (herbivores) - eat producers
Decomposers
o Bacteria and fungi that break down dead and decaying organisms
The Sulfur Cycle
o Bacteria-driven cycle o Most sulfur is underground in sedimentary rocks and minerals o Available in other forms like SOX, H2SO4, H2S o Sulfur gas is a minor part of the atmosphere, but movement of sulfur is substantial o Animals get sulfur from plant protein o Burning coal releases sulfur - causes acid deposition
Maximum Population Growth
o Biotic potential: maximum rate of increase under ideal conditions and affected by factors - history characteristics o Life history characteristics: age at first reproduction, reproductive fraction of life span, number of reproductive periods/events, number of offspring per reproductive event o Large organisms (whales, elephants) have lesser biotic potential o Small organisms (microorganisms) have greater biotic potentials
Desertification
o Caused largely by animal grazing/land converted for agriculture o Leads to loss of topsoil, increased soil salinity, damaged vegetation
Secondary Succession
o Change in species composition after a disturbance in an area previously inhabited - ex: abandoned farmland, forest fire, clear-cut forest o Soil already present o Can take over 100 years to occur o Typically: crabgrass->horseweed->pine trees->hardwood trees
Primary Succession
o Change of species over time in a previously uninhabited environment o No soil, bare rock surfaces o Begins with pioneer community composed of acidic lichens that break up rock, form soil o Lichens->mosses->shrubs->eventually specific trees
Global Climate Change
o Climate variation is normal, but global temperatures are increasing at an unprecedented rate o Climate is affected by human activities: increased release of CO2/greenhouse gases, industrial processes, fossil fuel consumption, deforestation, land use
Ecosystem
o Community and physical environment
Boreal Forest/Taiga
o Coniferous forests of pine, spruce, fir o In Northern Hemisphere, just south of tundra o Winters extremely cold and severe o Little precipitation - 20 inches/year o Acidic soil, poor minerals o Ponds and lakes dug by glaciers o Caribou, wolves, bear, moose, rodents, rabbits, lynx, birds in the summer, insects o Top source of industrial wood and fiber - leads to massive deforestation
Temperate Rain Forest
o Coniferous rain forest with high precipitation, dense fog, cool weather o Northwest coast of North America, Southeast Australia, South America o Mild winters, cool summers o Slow decay, poor soil o Hemlock, fir, cedar, spruce, epiphytes, mosses, lichens, ferns o Squirrels, wood rats, elk, mule deer, birds, amphibians, reptiles o High producer of lumber and pulpwood - overharvesting old-growth forest an issue
Demographics of Countries
o Demographics: the applied branch of sociology that deals with population statistics o Developed countries and developing countries: based on population growth rates, degree of industrialization, relative prosperity o GNI PPP: gross national income in purchasing power parity - when divided by population - GNI in PPP indicates the amount of goods and services an average citizen of that particular country could buy in the US o Average GNI PPP in the US is $45,640; worldwide average of GNI PPP is $10,240 o Infant mortality rate: number of deaths under age 1 per 1,000 live births o Replacement-level fertility: number of children a couple must produce to "replace" themselves - estimated 2.1 to compensate for not reaching reproductive age o Total fertility rate: average number of children born to each woman o Highly developed countries: lowest infant mortality rates and lowest b o Moderately developed countries: higher b and higher infant mortality rates than developed countries o Less developed countries: have shortest life expectancies, highest (b) and highest infant mortality rates o The population in many developing countries is approaching stabilization o Fertility rates in several countries have declined, many still exceed replacement-level fertility
Relationship between Population and Resources
o Developing countries export their natural resources to highly developed countries - developed countries already exploited their own resources o Larger population consumes more resources, causes more environmental damage than a smaller population o Not all people consume the same amount of resources - consumption based on economic status, culture, other economic and social factors
Brackish Ecosystem: Estuaries
o Estuary: coastal body of water, partly surrounded by land - access to ocean and freshwater from a river o Water levels rise and fall with tides o Salinity fluctuates from fresh water to brackish o Highly productive ecosystems with rapid nutrient circulation o Salt marshes: shallow wetlands with salt-tolerant grasses o Mangrove forests: tropical equivalent of salt marshes - significant losses due to coastal development and aquaculture
Temperate Deciduous Forest
o Forest biome that occurs in temperate areas - precipitation ranges from 30-50 inches/year o Hot summers, cold winters o Topsoil rich in organic matter o Broad-leaf hardwood trees that lose leaves seasonally o Originally puma, wolves, bison - now absent o Deer, bears, small mammals, birds o Original forests in Europe and North America - largely destroyed by logging and urbanization
Evidence for Evolution
o Fossil Record: show how organisms evolved over time o Comparative Anatomy: similarities among organisms demonstrate how they are related o Biogeography: study of geographic locations of organisms o Molecular Biology: showing relationships on a molecular level like sharing an enzyme or nucleotide base
Aquatic Ecosystems
o Freshwater or saltwater o Freshwater ecosystems; include standing-water (lakes/ponds), flowing-water (rivers/streams) and wetlands (marshes and swamps) o Categories of organisms: plankton (phytoplankton, zoo plankton), nekton (fish, turtles), benthos (bottom-dwellers)
Population Growth Scale Rates
o Global Scale Growth Rate: -(r) = (b) - (d) ; b = birth rate; d= death rate o Local Scale Growth Rate: -(r) = (b-d) + (i-e) ; i = immigration; e = emigration o Increasing Population: -r > (d< b) o Decreasing Population: -r < 0 (d>b) o Stable Population: -r = 0 (d = b)
Ecological Pyramids
o Graphically represent the relative energy values of each trophic level o Pyramids of energy illustrate how energy dissipates into the environment as it moves from one trophic level to the next o Pyramid of numbers shows the number of organisms at each trophic level in a given ecosystem
Ecosystem Productivity (GPP & NPP)
o Gross Primary Productivity: rate at which energy is captured during photosynthesis o Net Primary Productivity: amount of biomass found in excess of that broken down by a plant during cellular respiration - expressed in grams of dry matter per square meter per year for selected ecosystems
Population
o Group of the same organisms of the same species that live in the same place at the same time
Projecting Global Population
o Human population continues to increase o R has declined over the last few decades o Global average of number of children born to each woman is 2.5
Environmental Science as a Study
o Interdisciplinary study of humanity's relationship with other organisms and the physical environment o Combines information from many fields: biology, geology, geography, chemistry, economics, agriculture, law, politics, ethics o includes ecology, atmospheric science, environmental chemistry, and geoscience
Carrying Capacity (K)
o K: largest population a particular environment can support long term if there are no changes in that environment o K changes in response to environmental changes o At K - r is nearly zero as population size levels off o Earth's K: range from 4 billion to 16 billion - factors affected by differences in fertility rate, resource consumption, technological innovations, waste generation, overall lifestyle
Biome
o Large, relatively distinct terrestrial region with similar climate, soil, plants, and animals, regardless of where it occurs in the world o Encompasses many interacting ecosystems o Level of organization above community, ecosystem, landscape o Temperature and precipitation - have predominant effect on biome distribution o Also affected by elevation
Advances in Global Health
o Leads to decrease in d o Greater food production o Better and more accessible medical care o Improved water quality o Improved sanitation
Tropical Rain Forest
o Lush, species rich forest that occurs where climate is warm and moist year-round o Rains almost daily - 80-180 inches/year o Weathered, mineral-poor soil o High species richness and diversity o Three layers of vegetation o High rate of decomposition o Seasonal precipitation o Industrial expansion, human population growth - threaten the rain forests
Freshwater Wetlands
o Marshes with grass-like plants, swamps with woody shrubs o Productive plant communities o Shallow fresh water cover for at least part of the year o Water-tolerant vegetation o Waterlogged soils - anaerobic, low rate of decomposition, rich in organic material o Ecosystem services: include wildlife habitat, flood mitigation, filtration of ground water o Wetlands threatened by pollution, development, agriculture
Biogeochemical Cycles
o Matter: material of which organisms are composed o Biogeochemical: involves biological, geological, chemical processes o Humans have great influence o Cycling vs. flow: matter cycles through ecosystem, energy flows through the ecosystem o Includes carbon, hydrologic, nitrogen, sulfur, phosphorus cycles
The Cycling of Matter in Ecosystems
o Matter: material that makes up organisms, moves in cycles - biogeochemical cycles o Matter cycles between biotic and abiotic environments as it moves from one ecosystem to another
Chaparral
o Mild/moist winters, hot/dry summers o "Mediterranean climate" o dominated by small-leaved evergreen shrubs, small trees o lush vegetation during rainy winter season o wildfires common in late summer and autumn - many fire adapted plants grow after a fire o thin, unfertile soil
Deforestation
o Millions of hectares of forest lost annually o Loss of biodiversity o Loss of habitat for plants and animals o Deforested areas release CO2 o Deforestation affects local climates
The Nitrogen Cycle
o Nitrogen: essential component of proteins and nucleic acids o Atmosphere is 78% nitrogen gas o 5 Steps in which nitrogen cycles between abiotic environment and organisms: 1. Nitrogen fixation 2. Nitrification 3. Assimilation 4. Ammonification 5. Denitrification
The Flow of Energy Through Ecosystems
o Producers, consumers, decomposers: the 3 categories based on how nourishment is obtained o Energy Flow: the passage of energy in a one-way direction through an ecosystem - occurs in food chains o Trophic level: each level in a food chain o Energy is lost as heat along the way - number of steps in a food chain is limited, less energy is available for organisms at the higher trophic levels
Landscape
o Region that includes several interacting ecosystems o Landscape ecology studies the connections among ecosystems in a given region o Biosphere: layer of Earth that contains all living organisms
Science as Process
o Science is a body of knowledge and systematic process o Science involves data collection and interpretation o Scientific Method: used to understand the principles that govern the operation of the natural world o Science is constantly evolving - as new evidence comes to light conclusions may change o Scientific goal: explain events in nature
Sustainability and the Environment
o Sustainability: the ability to meet current needs without compromising the ability of future generations to meet their needs - based on several ideas: effects of our actions on the environment, the Earth's resources are finite, understanding impacts of consumption, shared responsibility for environmental sustainability
Temperate Grassland
o Tallgrass prairies, shortgrass prairies o Hot summers, cold winters, less rainfall than in temperate deciduous forest biome o Soil rich in organic matter o Over 90% of tallgrass prairies plowed for agriculture - North America's rarest biome
Energy (Potential and Kinetic)
o The ability to do work o Potential energy: stored energy o Kinetic energy: energy of motion
Predation
o The consumption of one species by another o Co-evolutionary "arms race" - predators evolve to better catch prey and prey evolve to better escape predator o To avoid predation: social behavior can decrease predation, chemical defense in prey, camouflage to hide from predators
Charles Darwin & Evolution
o The cumulative genetic changes in populations that occur during successive generations o Charles Darwin: proposed mechanism of evolution in "The Origin of Species by Means of Natural Selection" in 1859 o Idea that the environment plays a crucial role in which traits are inherited o Accumulation of favorable traits leads to increased survival
Environmental Resistance
o The environment controls population size o Limits placed on exponential growth o Availability of food, water, shelter, other resources - results in increases in competition, predation, disease - eventually b declines and d increases
The Carbon Cycle
o The global movement of carbon between the abiotic environment (atmosphere, ocean) and organisms o Atmosphere/oceanàphotosynthesisàcellular respiration/combustion/decompositionàatmosphere/ocean o Carbon is an essential component of organisms' molecules, also essential component of abiotic environment o 0.04% of the atmosphere o needed to make proteins and carbohydrates o present in several forms like CO2, HCO3, CaCO3 o photosynthesis fixes carbon from CO2 into carbohydrates o fossil fuels, coal, oil, natural gas - deposits of carbon compounds
Competition
o The interaction among organisms that vie for the same resources in an ecosystem like food or living space o Intraspecific competition and interspecific competition
Age Structure
o The number and proportion of people at each age in a population o Helps predict future population growth o Age structure diagrams: illustrate the number of males and females at each age from birth to death
Thermodynamics
o The study of energy and its transformations
Ecology
o The study of the interactions among organisms and between organisms and their abiotic environment o Linked to geology, chemistry, physics o Levels of organization: population, communities, ecosystem o Individual à population à community à ecosystem à biome à biosphere
Arctic Tundra
o Treeless biome in far north - consists of boggy plains covered by lichens and mosses o Harsh, cold winters, extremely short summers, seasonal snow melting o Alpine tundra occurs at higher elevations of mountains above the tree line o Low primary productivity and resilience o Permafrost: layer of permanently frozen ground - climate change causing permafrost to thaw
Savanna
o Tropical grassland o Widely scattered/clump trees o Low/intense seasonal rainfall - 34-60 inches/year with prolonged dry periods o Large herds of herbivores like wildebeest, antelope, giraffe, zebra, elephant o Large carnivores like lions and hyenas o Savanna lost as land, converted into rangeland for cattle o Africa, North Australia, South America, West India
The Hydrologic Cycle (water cycle)
o Water circulates among the ocean, land, and atmosphere o creates a renewable supply of water for terrestrial organisms: runoff is water from land to rivers and lakes, watersheds are areas of land where runoff drains o climate change and aerosols (type of air pollutant) - weaken hydrologic cycle
Flowing-Water Ecosystems
o Water flows in a current o Highly variable - surrounding environment changes between source and mouth o Types of organisms depend on strength of current o Adverse human impacts like pollution and dam construction
The Scientific Method
o Way a scientist approaches a problem by formulating a hypothesis and then testing it
Evolution through Natural Selection
o adaptions and evolutionary modifications improve chance of survival and reproductive success o 4 Observations that guide natural selection: 1. High reproductive capacity 2. Limits on population growth 3. Heritable variation 4. Differential reproductive success o Modern synthesis is a combination of Natural Selection and principles of genetics o Mutations provide genetic variation
Energy Producers
o manufacture large organic molecules from simple inorganic molecules o potential food for other organisms o plants: most significant producers on land
Green Roofs
o on tops of buildings o Partially covered/completely covered with vegetation and soil o Provide environmental benefits: reduce heating costs in winter/cooling costs in summer, filter rainwater pollutants, reduce storm water in sewers, provide wildlife habitats
Desert
o plant growth limited by lack of precipitation o found in temperate and tropical regions o daily temperature extremes o less than 10 inches of rain/year o sparse vegetation that includes cacti, yucca, sagebrush o soil is low in organic matter, high in mineral content o animals: typically small, nocturnal - insects, arachnids, desert-adapted amphibians, reptiles o threatened by human encroachment and environmental damage from off-road vehicles - soil easily eroded and less vegetation grows to support native animals
Ecological Footprint
o the amount of land and water needed to provide energy, housing, transportation per person o allotted global footprint: 4.3 acres o average global footprint: 6.7 acres - overshoot
Demographic Transition
o the process whereby a country moves from high b and d to low b and d o 4 demographic stages that show how a population progresses as its society becomes industrialized: § Stage 1: Preindustrial § Stage 2: Transitional § Stage 3: Industrial § Stage 4: Postindustrial
Ecological Niches
o the totality of an organism's adaptions, its use of resources, and the lifestyle to which it is fitted - includes habitat o Niche: the totality of an organism's adaptions, its use of resources, lifestyle to which it is fitted - describes the place and function of an organism within the ecosystem, takes into account all aspects of an organism's existence, the "way of life of an organism" o Habitat: part of an organism's niche - place where the organism lives o Fundamental niche: the potential, idealized niche o Realized niche: the actual niche an organism occupies
