ECOLOGY 0370 Introduction 1 What is ecology Haekel 1866 study of relationship of animals to their environment Now expanded to all organisms Yet vague what is really studied Some basic observations o Many species on Earth approx 1 9 million named and described species o Each has unique limited distribution unique geographical locations no species that occurs everywhere o Abundance of each species varies in space and time o Not all species occur together o Species occur in limited sets or communities Why should the world be organized like this a General definitions Scientific natural history Natural history the study of nature and natural phenomena Not quite appropriate includes topics peripheral to ecology e g astronomy Structure and function in nature The working of nature But seems to imply homeostasis o Gaia hypothesis world has world wide homeostasis o we don t know if it is homeostatic b Formal definition Ecology is the scientific study of the interactions that determine the distribution abundance and co occurrence of organisms simple enough but subtle interactions occur between organisms and their environments i ii environment includes other organisms including conspecifics conspecifics members of a given species focuses on organisms not environments unlike environmental science also deals with who occurs with whom and why and who doesn t occur with whom and why community membership i ii i ii iii iv c Relationship to other biological sciences i ii Ecology complex synthetic Has close ties to many natural sciences i Genetics ii Evolution iii Behavior iv Phyiology d History i 2 Goals of ecology a Description See handout of dates and events o EX Indigo bunting yearly cycle o Breeds in Eastern US o Migrates south in fall o Stays in central America during winter o Migrates north b Identification of proximate immediate causes o EX causal cue of Indigo bunting fall migration o Stephen Emlen proposed difference in photo period experiment with birds in planetarium altered photo periods and measured footprints made with inkpad found birds wanted to migrate south in response to mid August photo period c Identification of ultimate evolutionary causes o Causes that give rise to proximal causes o EX evolutionary reason for migration d Prediction use knowledge to predict events o EX population response to global warming American Beech tree response to temperature e Application applied ecology o EX steps to protect extinction under global warming a Primarily populations and communities Population group of conspecifics Community set of populations that co occur b Also individuals ecosystems and the biosphere Biosphere thin shell of Earth capable of supporting life o Ecosystem set of communities and their abiotic surroundings Communities Populations o Individuals ramets 3 Levels of Study 4 The scientific method in ecology Handout 5 Approaches a Experimental Keep as many variables as possible the same Manipulate one variable chart response o Eliminates confounding variables Requires a control group and a treatment group b Modeling Simulation Establish qualitative or quantitative image of the basics of complex systems Run model or simulation Determine if result is a pattern seen in nature c Comparative Take advantage of similar natural circumstances that differ in some or few attributes o EX islands and island size Community smaller on smaller island Island size dictates the number of co occurring species