biol270chap_2_part1

biol270chap_2_part1 - Introduction to ecology Introduction...

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Unformatted text preview: Introduction to ecology Introduction to ecology Make observation Formulate hypothesis Test hypothesis Collect data Oldest science? Unique to humans? Interpret/analyze data Definition? Draw conclusions Not preservation or conservation Not a political movement, such as the various Green parties in Europe Not Human Ecology (new term for Home economics) Originally Oekologie, from the Greek word Oikos, meaning "Home" or home life of organisms, (same root as economic, in fact ecology has borrowed some economic concepts i.e., resource allocation, cost benefit ratios, optimization theory.) First used without definition by Thoreau in 19th century, Not widely used until the 1960s The Roots of Ecology The Roots of Ecology Thomas Malthus econonist 1766-1834 Tradition of Natural History philosophy Charles Darwin Natural selection Darwin’s grandfather dabbled in evolutionary theory Evolution and adaptation Two central themes in ecology Charles Lyell geologist (dynamic earth) Alfred Russell Wallace Roots con. Roots con. Plant geographers Natural History Mendel Darwin “Animal Ecology” Elton 1927 Population ecology Europe North America Succession e.g., Clements Plant associations Lindeman 1942 “the Trophic – Dynamic Aspect of Ecology Evolutionary ecology Ecosystem ecology Community ecology Behavior ecology First defined by Ernst Haeckel in 1869 as The total relations of the animal to both its organic and inorganic environment“ Charles Elton (1927) "Scientific natural history“ Eugene Odum (1963) "The study of the structure and function of nature“ Charles Krebs (1972) "The scientific study of the interactions that determine the distribution and abundance of organisms“ Townsend, Begon and Harper (2003) “The scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance” Ecology defined Ecology defined Things to keep in mind Things to keep in mind Ecology is a science, and ecologists therefore try to describe, explain, understand, and predict Explanations can be proximate – the immediate cause, e.g., the current distribution of a species is based on habitat or food preferences ultimate – the underlying reasons for such preferences, e.g., a species current habitat or food preference is the result of past competition with other species Of Hierarchies, Scales, Levels and Of Hierarchies, Scales, Levels and Systems in Ecology Scale Scales of time and space Scales and levels Biological hierarchies Systems and hierarchies Scale­ a spatial/temporal extent Scale­ Geographic big=1:2400; small=1:100,000 Ecological big=regional, landscape; small=stand, patch, stream Scale of the observation (The study bias) Grain ­ sample unit Extent – sample site, domain = “bounded universe in which the dialog between conceptual constructs and reality is conducted” Pickett et al. (1994) Together these form a filter though which ecological phenomena will pass Phenomena smaller than grain not captured Phenomena larger than extent not captured Scales of time and space 10,00 yr landscape forest, community patch stand population tree canopy leaf 1 cm 100km Log Temporal scale month Log spatial scale Scales and Levels Scales and Levels Scale­ simply needs a domain, but are often identified by a pattern within. Do they need an observer? Natural phenomena? Level­ implies interaction and organization Of Hierarchies, Scales, Levels and Of Hierarchies, Scales, Levels and Systems in Ecology Biological Hierarchies Eachlevel acts as a system (i.e., interacting components, remember that the whole is greater than the sum of it parts) Hierarchies consist of interacting levels of organization Hierarchy Theory Hierarchy Theory L+1 S(a) S(b) Level S(a)a S(a)b S(b)a S(b)b L-1 System S(a)ac S(a)aa S(a)ab What's driving the landscape What's driving the landscape C oastal plain ve tation com unitie aregove d by e ge m s rne daphic topographic fe s t opographic ature + Space (e Walke and Pe t 1983, Jone e al. 1984, Pe t and Allard 1993, .g., r e st e Kirkm e al. 2001) an Kirkm t Geomorphology (topography, soils) Climate (lightening/fire) - Landscape mosaic (vegetation patches) How Ecosystems Are Structured Abiotics (moisture and temperature) predict Ecological structures: Ecological structures: Plants (forest) predict Animals Prey (hare) Predator (lynx) A biological/ecological hierarchy A biological/ecological hierarchy Biosphere Biome Ecosystem Community Species Population Individual A biological hierarchy A biological hierarchy Individual: a single member of a population Population: number of co­occurring/interbreeding individuals of one species that make up a definable group. Species: a fine scale taxonomic class defined by an evolutionary relationship, and generally limited by interbreeding (International Code of Zoological Nomenclature “The Code”­ no single species concept) There are multiple species concepts There are multiple species concepts Typological species: a "classical" method of determining species, such as with Linnaeus early in evolutionary theory. However, phenotypes do not always constitute different species (e.g., a 4­winged Drosophila born to a 2­winged mother is not a different species) Biological species: A set of actually or potentially interbreeding populations Phylogenetic species: A group of organisms that shares an ancestor; a lineage that maintains its integrity with respect to other lineages through both time and space A biological/ecological hierarchy A biological/ecological hierarchy Community: collection or assemblage of plants, animals, and microbes. Ecosystem: The interacting biotic and abiotic components of a specific time and space. Biome: a grouping of similar ecosystems (e.g., tropical forest, grassland) Biosphere: all biotic and abiotic factors on earth interacting as a unified ecosystem Ecotones on Land Ecotones on Land Shares many of the species and characteristics of both ecosystems May also include unique conditions that support distinctive plant and animal species Fuzzy (just like ecosystems) Terrestrial­to­aquatic­system ecotone Terrestrial­to­aquatic­system ecotone Fuzzy (e.g., aquatic terrestrial transition zone ATTZ) Shares many of the species and characteristics of both ecosystems May also include unique conditions that support distinctive plant and animal species Aquatic Terrestrial Transition Zone (ATTZ) Aquatic Terrestrial Transition Zone (ATTZ) Abiotic and biotic factors Abiotic and biotic factors Condition: abiotic factors that effects individuals but are not consumed (e.g., temp.) Resource: abiotic or biotic factors that effects individuals and are consumed or excluded from other by its use (e.g., light, nesting cavity). Survival Curves Illustrate Law of Survival Curves Illustrate Law of Limiting Factors Abiotic Factors Abiotic Factors Law of Limiting Factors: Every species (both plant and animal) has an optimum range, zones of stress, and limits of tolerance with respectto every physical factor. Liebig’s law of minimums: any factor being outside the optimal range will cause stress and limit growth and survival. Compare the “tolerance” differences for a trout and a catfish: temperature (cold or warm). oxygen concentration (high or low). salinity (high or low). Application of the Law of Limiting Application of the Law of Limiting Factors Oxygen Tolerance Curves for Two Oxygen Tolerance Curves for Two Different Fish Species Diagram the temperature tolerance curves for each fish species. Climate and Major Biomes Climate and Major Biomes Climate: the average temperature and precipitation (the weather) that may be expected through the entire year Effects of Latitude and Altitude Effects of Latitude and Altitude Microclimates Microclimates Ecological niche: the range of environmental Ecological niche: conditions and resources needed for a species to exist Ecological niche­ Ecological niche­ Fundamental niche: the total range of environmental conditions and resources that are suitable for existence Realized niche: the portion of the fundamental niche actually occupied by the species (includes the effects of competition, predations) Ecological niche Ecological niche ...
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