Chapter 1 The Origin of Species 1 1 Overview of Ecology Ecology is the study of relationships between organisms and the environment Human survival has depended upon how well we could observe variations in the environment and predict the responses of Chapter 1 Introduction to Ecology 1 organisms to those variations processes Ecologists study environmental relationships ranging from those of individual organisms to factors influencing global scale Physiological ecologists have emphasized the evolution a process by which populations change over time of physiological and anatomical mechanisms by which organisms solve problems posed by physical and chemical variation in the environment Behavioral ecologists have focused principally on evolution of behaviors that allow animals to survive and reproduce in the face of environmental variation Both physiological ecology and behavioral ecology are both guided by evolutionary theory Population ecology is centered on the factors influencing population structure and process where a population is a group of individuals of a single species inhabiting a defined area Includes adaptation extinction the distribution and abundance of species population growth and regulation and variation in the reproductive ecology of species Biological components of ecology include predation parasitism and competition Ecological community is an association of interacting species links community ecology with the ecology of interaction Community ecologists concentrate on the organisms inhabiting the area ecosystem ecologist include the physical and chemical factors influencing the community and focus on processes such as energy flow and decomposition Landscape Ecology the study of exchanges of materials energy and organisms among ecosystems Geographic Ecology study of regions that are large scale and long term regional processes that leads to the large spatial scale and highest level of ecological organization the biosphere the portion of the earth that support life including the land water and atmosphere Aeroecology the interdisciplinary study of the ecology of the earth atmosphere boundary Urban Ecology the study of urban areas as complex dynamic ecological systems influenced by interconnected biological physical and social components 1 2 Sampling Ecological Research The Ecology of Forest Birds Old Tools and New Ecologists design their studies based on their research questions the temporal and spatial scale of their studies and available research tools In 1955 MacArthur was studying the ecology of five species of warblers that lived in northeastern North America Theory predicted that two species with identical ecological requirements would compete with each other and that as a consequence they could not live in the same environment indefinitely His quantitative observations demonstrated that the five warbler species in his study area fed in different zones in He concluded that feeding in different zones may reduce competition among the warblers of spruce spruce trees forests Ecologists turn increasingly to understand the ecology of migratory birds by using stable isotope analysis a chemical element having different atomic masses as a result of having different number of neutrons Chapter 1 Introduction to Ecology 2 Stable isotopes have proven useful in the study of ecological processes for example identifying food sources because the proportions of various isotopes differ across the environment Forest Canopy Research A Physical and Scientific Frontier Ecosystem includes all the organisms that live in an area and the physical environment with which those organisms Many ecosystem studies have focused on nutrients the raw materials that an organism must acquire from the interact environment to live Nalini Nadkarni is an ecologist who studied the budgets of nutrients such as nitrogen phosphorus or calcium and their distribution within an ecosystem Because of leaching by heavy rains many rain forest soils are poor in nutrients such as nitrogen and phosphorus Nadkarni research in the treetops uncovered where nutrients are stored The nutrients stores in the rain forest canopy are associated with epiphytes Epiphytes are plants such as orchids and ferns that live on the branches and trunks of other plants They are not parasitic they do not derive their nutrition from the plant they grow on Nadkarni s research showed that in both temperate and tropical rain forests trees access these nutrient stores by sending out roots from their trunks and branches high above the ground Climatic and Ecological Change Past and Future sediments and evolutionary studies area Two approaches that provide insights into long term and large scale processes are studies of pollen preserved in lake Pollen preserved in the sediments of individual lakes can be use to reconstruct the history of vegetation in the As climate changes plant populations simultaneously change their geographic distribution and undergo the evolutionary process of adaptation which increases their ability to live in the new climatic regime Natural history is the foundation on which ecologists build modern ecology for which evolution provides a conceptual framework Chapter 1 Summary research tools Ecologists study environmental relationships ranging from those of individual organisms to factors influencing global scale processes The research focus and questions posed by ecologists differ across the levels of ecological organization Ecologists design their studies based on their research questions the temporal and spatial scale of their studies and available Ecology the study of relationships between organisms and the environment Davis studied vegetation moving across the North America continent over a span of thousands of years MacArthur studied birds in contemporary forests Nadkarni studied the rain forest canopy