Bio 3030 Week 4
Bio 3030 Week 4 Biol 3030
Popular in Ecology
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This 5 page Class Notes was uploaded by Aurora Moberly on Saturday September 17, 2016. The Class Notes belongs to Biol 3030 at Southern Utah University taught by Dr. Rachel Bolus in Fall 2016. Since its upload, it has received 4 views. For similar materials see Ecology in Biology at Southern Utah University.
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Date Created: 09/17/16
Introduction to Ecology Ecology: The study of how organisms affect and are affected by other organisms and their environment Levels of Biological Organization: Organism, populations, communities, ecosystems, landscapes, entire biosphere Population: A group of individuals of a single species that live in a particular area and interact with one another Community: An association of interacting populations of different species that live in the same area Ecosystem: Community of organisms plus the physical environment in which they live Biotic: Living components of a natural system Abiotic: Physical environment of a natural system Landscapes: Areas that vary substantially from one place to another and typically include multiple ecosystems Biosphere: All living organisms on Earth plus the environments that they live in; Highest level of biological organization Ecologists use three main tools for research: Observation, Experiments, Models Ecologists must select an appropriate scale of time, measurements, ect to conduct their research in Adaptation: A feature of an organism that improves its ability to survive or reproduce in its environment Producer: An organism that uses energy from an external source (ie sun) to produce its own food without having to eat other organisms or their remains Consumer: An organism that obtains energy by eating other organisms or their remains Nutrient Cycle: The cyclic movement of a nutrient between organisms and the physical environment Climate Change: Directional climate change that occurs over three decades or longer Conservation Biology Conservation Biology: An integrative discipline that applies the principles of ecology to the protection of biodiversity; The scientific study of phenomena that affect the maintenance, loss and restoration of biodiversity Population is affected by the birthdeath rates, per capita offspring, generation time (age of individual reproducing) Biodiversity: All living things at all scales of organization Anthropocene: Period of the Earth in which the crust has been so affected by the activity of humans that there will be a distinct geological layer recording it The Sixth Major Extinction: There have been five major extinctions before this one but this is the only major extinction to have been caused by an organismhumans History of Biodiversity: John Muir and Henry David Thoreau called for the preservation of nature for spiritual reasons; Petitioned congress to begin the National Park Service Henry David Thoreau wrote papers on natural history such as “On Civil Disobedience” “Walden Pond” Gifford Pinchot was the first chief of the U.S. Forest Service Aldo Leopold: Was a forester who studied the ecological relationships of communities and saw species as interconnected groups that depend on each other; Wrote “A Sand County Almanac” Ecosystem Services: Nutrient cycling, primary production food, disease regulation, air purification, ect Primary threats to biodiversity are habitat loss, invasive species, overexploitation, pollution, disease, climate change The most important threats are habitat degradation, fragmentation and loss Endangered Species Act (1973) was passed to provide a means whereby the ecosystems on which endangered and threatened species depend on may be conserved and to provide a program for the conservation of these species Passed in response to the overexploitation of the American bison and passenger pigeon Habitat Loss: Outright conversion of a habitat to another use Habitat Fragmentation: The breakup of a oncecontinuous habitat into a series of habitat patches amid a humandominated landscape Edge Effects: Abiotic and biotic changes that are associated with habitat boundaries; Ex. Increased predation risk, solar radiation, exposure to invasive Habitat Degradation: Changes that reduce the quality of the habitat for many species Exotics: Organisms that are introduced to a new part of the world beyond their natural range by human intervention either accidently or on purpose Exotics disrupt local food webs and are often invasive Invasive Species: Nonnative, introduced species that sustain growing populations and have large effects on communities Natural is a paradox it both excludes and includes mankind Population Viability Analysis (PVA): A model of the factors that affect the trajectory of a species, including predicting whether and when a population or species may become extinct; Also a good way of theoretically testing how different management techniques may affect species Urban Ecology: Studying the nature of cities Landscape Ecology Landscape Ecology: Sub discipline of ecology that examines spatial patterns and their relationship to ecological processes Landscape: An area in which at least one element is spatially heterogeneous (varies from one place to another); Often include multiple ecosystems Mosaic: Pattern of heterogeneous elements that make up a landscape There is a biotic flow between habitat patches in the mosaic as individuals or gametes move between them; For this flow to occur there needs to be habitat connectivity or the surrounding habitat (matrix) must be of a type that allows dispersal Landscape genetics combines theory from landscape ecology, population genetics, and movement biology to predict how gene flow is affected by individuals’ movements across a landscape. Fragmentation: A landscape is made of distinct patches of habitat that are fragmented from each other Connectivity: The distance between patches, how connected they are and how easy it is for organisms and resources to move between them; Inversely related to fragmentation Four processes that affect the patterns of habitat 1. Abiotic: Geography, geology, climate 2. Biotic: Life history, species interactions, movement and dispersal 3. Disturbance: Sudden changes in landscape 4. Succession: Gradual changes in landscape Geographical Information System (GIS): A way for scientists to describe landscapes; A way of mapping different information together to understand patterns and process Grain: The size of the smallest homogeneous unit of study, determines the resolution at which we view the landscape Extent: The area or time period encompassed by a study Grain and extent have to be balance, if you have a small extent you usually need a finer grain Levels of Heterogeneity within a Landscape: 1. Cells 2. Patches: Contiguous area of a single habitat type 3. Aggregates of similar patches 4. Landscape Metrics: How we measure patch or landscape variation Movement Ecology: The study of the movement of organisms; Field is new and growing because of technological advances that allow us to track organisms better Organisms move locations to reproduce, avoid a predator, find food and water, avoid bad weather Biomechanics: The study of the physics of movement accounting for internal and external forces Plants can move as well animals via seeds exploding Organisms know where to move based on cognitive processes, orientation mechanisms and passive dispersal Cognitive processes is when organisms use landmark recognition and predator avoidance to move Orientation mechanism is when genetic mechanisms cause the organism to orient their body in a certain direction to move depending on the season Passive dispersal is when organisms rely on their environment to move them To model movement of organisms we use stochastic (random) models because they give a good null model to compare with observed movements Habitat resistance models create movement paths based on the landscape the organism occupies Each cell on the map has a value that describes how easy it is for a species to move across Low values mean it’s easier to move Resistance mapping uses multiple movement models to model the path of least resistance for an organism Circuit Modeling: Modeling that identifies the places that have the best conditions for movement based on environmental variation across the landscape Evolution & Drift and Adaptation Evolution: A process of descent with modification; Allele frequency change in a population over time Evolution doesn’t happen to an individual it happens to a population Can only occur to traits that are heritable Five major mechanisms of evolution 1. Mutation 2. Recombination 3. Gene Flow 4. Natural selection 5. Genetic Drift All of these processes occur at the same time at different strengths Mutation, recombination, gene flow increase genetic variation Natural selection, genetic drift decreases genetic variation Mutation: A change in the DNA of a gene; Critical to evolution because it brings about new alleles Recombination: The production of offspring that have combinations of alleles that differ from those in either of their parents Gene Flow: Occurs when alleles are transferred from one population to another via the movement of individuals or gametes 1. Gene flow causes population to be more similar to one another genetically 2. Gene flow can introduce new alleles into a population Can limit local adaptation Natural Selection: The process by which individuals with certain heritable characteristics survive and reproduce more successfully than other individuals because of those characteristics First Fact: Populations could increase exponentially given that they reproduce more than is needed to replace the population Second Fact: Even though populations could grow exponentially, most don’t Third Fact: There are not enough resources to go around Fourth Fact: All individuals are unique Fifth Fact: These individual differences are heritable First Inference: There is a struggle for existence among individuals Second Inference: There is differential survival and reproduction among individuals with different, heritable characteristics Third Inference: Differential survival will lead to evolution over time as those with beneficial allelses will survive longer and pass on the allele to more of their more numerous offspring Adaptations: Heritable features of organisms that improve their ability to survive and reproduce Individuals themselves do not evolve, the population as a whole moves towards favorable traits causing the population to evolve Fixation: An allele that occurs in a population at a frequency of 100% Alleles reach fixation more quickly in smaller populations Genetic Drift: Chance events affect which alleles are passed from one generation to the next 1. Genetic drift can cause allele frequencies to fluctuate randomly in small populations over time causing some alleles to disappear or to reach fixation 2. Genetic drift reduces the genetic variation of the population 3. Genetic drift can increase the frequency of harmful allele 4. Genetic drift can increase genetic difference between populations Adaptive Evolution: A process of change in which traits that confer survival or reproductive advantages tend to increase in frequency over time Natural selection is the only evolutionary mechanism that consistently causes adaptive evolution Longterm patterns of evolution are shaped by processes such as speciation, mass extinction and adaptive radiation Geographic Variation: Variation in a species over its geographic range, can be a precursor to speciation Traits will differ because of differences in environments and will be nonheritable Speciation: The process by which one species splits into two or more species Most commonly occurs when a barrier prevents gene flow from one population to another Can also occur when two different species breed and the hybrid offspring survives and thrives Allopatric Speciation: Over time a population grows until it covers a broad geographic range and speciation occurs because there is no interbreeding, different environmental conditions, drift and gene flow between populations Sympatric Speciation: Populations diverge within the same geographic area causing speciation due to environmental variation and later sexual selection Ring Species: Combination of allopatric and sympatric, all populations are still touching but the population spreads out and loops back around to other populations there is no interbreeding because the populations have diverged enough Mass Extinction: Large proportions of Earth’s species were driven to extinction worldwide in a relatively short time, five have been known to happen Adaptive Radiation: Populations of a single species adapt to different parts of their environment and then become isolated genetically from each other Two part process 1. Adaptive evolution to a variable environment 2. Sexual selections that leads to additional assortive mating among populations Barriers to evolutionary perfection: 1. Lack of genetic variation 2. Evolutionary history 3. Tradeoffs between adaptive traits The Physical Environment The spatial patterns and temporal rhythms of life are shaped by the environment Weather refers to the current conditions of temperature, precipitation, humidity, wind and cloud cover Climate: The longterm average weather at a given location The climate system is driven by the balance between energy grains from solar radiation, reradiation by the atmosphere and energy losses due to infrared radiations from Earth’s surface, latent heat flux, sensible heat flex Latent Heat Flux: Heat loss due to evaporation Sensible Heat Flux: Energy transfer from the warm air immediately above Earths surface to the cooler atmosphere by convection and conduction Albedo: Amount of solar radiation that a surface reflects; Influenced by the presence and type of vegetation as well as by soil and topography A rough surface allows greater transfer of energy to the atmosphere by wind than a smooth surface because vegetation disrupts air flow Uplift: Warm air is less dense than cool air so as long as a pocket of air remains warmer than the surrounding air it will rise As warm air rises higher it expands, cooling the air; Cool air can’t hold as much water vapor as warm so the air continues to rise and cool the water vapor contained within it begins to condense into droplets and form clouds As warm air rises higher it expands, cooling the air; Cool air can’t hold as much water vapor as warm so the air continues to rise and cool the water vapor contained within it begins to condense into droplets and form clouds Subsidence: A downward movement of air in the atmosphere leading to the development of a highpressure cell The highpressure cell inhibits the formation of clouds, deserts are found at latitudes influenced by subsidence Hadley Cell: A largescale pattern of atmospheric circulation in each hemisphere caused by the tropical uplift of air Polar Cell: Atmospheric circulation cells that are formed above the north and south poles Ferrell Cell: Located inbetween the Hadley and polar cells Atmospheric circulation cells create surface wind patterns Winds flow from high pressure to low pressure Coriolis Effect: The apparent defection of air or water currents when viewed from a rotating reference point such as Earths surface Coriolis Effect and the difference in heat capacity between the oceans and the continents act on atmospheric circulation cells to determine the pattern of prevailing winds at Earth’s surface An oscillation in pressure cells causes weather deviations in global patterns El Nino Southern Oscillation: An oscillation of pressure cells and sea surface temperatures in the equatorial Pacific Ocean that causes widespread climatic variation and changes in upwelling currents Ocean currents are driven by surface winds, differences in water temperature, salinity Of the three R’s (reduce, reuse, recycle) reduce is the best for the environment Americans waste 3040% of all the food we produce and ship here Variation in oceanic temperatures and salinity cause variation is ocean water density which causes the Great Ocean Conveyor Belt Great Ocean Conveyor Belt: Causes mixing and effects current and climate across the globe, slow moving process Surface currents are affected by the wind, upwelling, rotation of the Earth and the locations and shapes of landforms Upwelling: Deep ocean water rises to the surface; Recirculates nutrients from the bottom of the ocean creating rich feeding grounds for organisms that must remain in the photic layer The moon affects currents by changing tides that produce local currents especially on the coast Biomes: Largescale biological communities shaped by the physical environment in which they are found Three types of biomes: 1. Marine Biomes (Defined by physical structures and characteristics) 2. Freshwater Aquatic Biomes (Defined by physical structures and characteristics) 3. Terrestrial Biomes (Defined by climate specifically temperature and precipitation) Marine Biomes: MarineCoastal Zones: Estuaries, salt marches, mangroves, rocky intertidal, sandy shores Shallow Water: Coral reefs, seagrass beds, kelp forests Freshwater Aquatic Systems: The smallest branches of a river are called first order streams that feed into second order and then third order and so on Community zones: Main, benthic, hyporheic Depth, flow and water chemistry can be affected by the contours of the land Ocean is categorized as its own biome but we recognize there are different divisions with different communities Terrestrial Biomes: Amount of precipitation is related to temperature; Type of vegetation in the area is dependent on precipitation and temperature Nine major terrestrial biome types 1. Tropical: Temp: Remains the same year round Precipitation: Remains high year round 2. Tropical Seasonal Forests/Savannas: Temp: Consistently warm Precipitation: Seasonal rains 3. Hot Desserts: Temp: Consistently high Precipitation: Very little amount 4. Temperate Grasslands: Temp: Seasonal temperature Precipitation: Dry winters and wet summers 5. Temperate Shrublands/Woodlands: Temp: Warm summers, cooler rest of year Precipitation: Dry summers, wet rest of year 6. Temperate Deciduous Forests: Temp: Seasonal Precipitation: Wet all year 7. Temperate Evergreen Forests: Temp: Seasonal Precipitation: Wet all year with peaks in summer and winter 8. Boreal Forests: Temp: Extremely cold for most of the year, periods in summer warm enough for growth Precipitation: Low throughout the year 9. Tundra: Temp: Extremely cold climate Precipitation: Low Other: No trees due to glaciers scraping out all of the trees
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