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Intertidal Zones Tropic of Cancer Equator Tropic of Capricorn 30ºS Stratification of Aquatic Biomes Chapter 52 An Introduction to Ecology and the Biosphere PowerPoint® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Overview: The Scope of Ecology • Ecology is the scientific study of the interactions between organisms and the environment • These interactions determine distribution of organisms and their abundance • Ecology reveals the richness of the biosphere Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Scope of Ecological Research • Ecologists work at levels ranging from individual organisms to the planet Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Organismal ecology studies how an organism’s structure, physiology, and (for animals) behavior meet environmental challenges Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-1 Fig. 52-2 Organismal ecology Population ecology Community ecology Ecosystem ecology Landscape ecology Global ecology Fig. 52-2a • A population is a group of individuals of the same species living in an area • Population ecology focuses on factors affecting how many individuals of a species live in an area Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-2b • A community is a group of populations of different species in an area • Community ecology deals with the whole array of interacting species in a community Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-2c • An ecosystem is the community of organisms in an area and the physical factors with which they interact • Ecosystem ecology emphasizes energy flow and chemical cycling among the various biotic and abiotic components Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-2d • A landscape is a mosaic of connected ecosystems • Landscape ecology deals with arrays of ecosystems and how they are arranged in a geographic region Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-2e • The biosphere is the global ecosystem, the sum of all the planet’s ecosystems • Global ecology examines the influence of energy and materials on organisms across the biosphere Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-2f Concept 52.1: Ecology integrates all areas of biological research and informs environmental decision making • Ecology has a long history as a descriptive science • It is also a rigorous experimental science Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-3 Trough Pipe “Dry” “Wet” “Ambient” Linking Ecology and Evolutionary Biology • Events that occur in ecological time affect life on the scale of evolutionary time Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ecology and Environmental Issues • Ecology provides the scientific understanding that underlies environmental issues • Ecologists make a distinction between science and advocacy • Rachel Carson is credited with starting the modern environmental movement with the publication of Silent Spring in 1962 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-4 Concept 52.2: Interactions between organisms and the environment limit the distribution of species • Ecologists have long recognized global and regional patterns of distribution of organisms within the biosphere • Biogeography is a good starting point for understanding what limits geographic distribution of species • Ecologists recognize two kinds of factors that determine distribution: biotic, or living factors, and abiotic, or nonliving factors Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-5 Kangaroos/km2 0–0.1 0.1–1 1–5 5–10 10–20 > 20 Limits of distribution • Ecologists consider multiple factors when attempting to explain the distribution of species Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-6 Why is species X absent from an area? Yes Area inaccessible or insufficient time Yes Does dispersal Habitat selection limit its Yes Predation, parasitism, Does behavior Chemical distribution? No competition, disease factors limit its Do biotic factors Water distribution? No (other species) Oxygen limit its Do abiotic factors Salinity No distribution? limit its pH distribution? Soil nutrients, etc. Temperature Physical Light factors Soil structure Fire Moisture, etc. Dispersal and Distribution • Dispersal is movement of individuals away from centers of high population density or from their area of origin • Dispersal contributes to global distribution of organisms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Natural Range Expansions • Natural range expansions show the influence of dispersal on distribution Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-7 Current 1970 1966 1965 1960 1961 1958 1943 1951 1937 1956 1970 Species Transplants • Species transplants include organisms that are intentionally or accidentally relocated from their original distribution • Species transplants can disrupt the communities or ecosystems to which they have been introduced Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Behavior and Habitat Selection • Some organisms do not occupy all of their potential range • Species distribution may be limited by habitat selection behavior Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Biotic Factors • Biotic factors that affect the distribution of organisms may include: – Interactions with other species – Predation – Competition Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-8 RESULTS 100 Both limpets and urchins removed 80 Sea urchin Only urchins removed 60 Limpet 40 Seaweed cover (%) 20 Only limpets removed Control (both urchins and limpets present) 0 August February August February 1982 1983 1983 1984 Abiotic Factors • Abiotic factors affecting distribution of organisms include: – Temperature – Water – Sunlight – Wind – Rocks and soil • Most abiotic factors vary in space and time Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Temperature • Environmental temperature is an important factor in distribution of organisms because of its effects on biological processes • Cells may freeze and rupture below 0°C, while most proteins denature above 45°C • Mammals and birds expend energy to regulate their internal temperature Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Water • Water availability in habitats is another important factor in species distribution • Desert organisms exhibit adaptations for water conservation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Salinity • Salt concentration affects water balance of organisms through osmosis • Few terrestrial organisms are adapted to high- salinity habitats Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Sunlight • Light intensity and quality affect photosynthesis • Water absorbs light, thus in aquatic environments most photosynthesis occurs near the surface • In deserts, high light levels increase temperature and can stress plants and animals Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-9 Rocks and Soil • Many characteristics of soil limit distribution of plants and thus the animals that feed upon them: – Physical structure – pH – Mineral composition Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Climate • Four major abiotic components of climate are temperature, water, sunlight, and wind • The long-term prevailing weather conditions in an area constitute its climate • Macroclimate consists of patterns on the global, regional, and local level • Microclimate consists of very fine patterns, such as those encountered by the community of organisms underneath a fallen log Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Global Climate Patterns • Global climate patterns are determined largely by solar energy and the planet’s movement in space • Sunlight intensity plays a major part in determining the Earth’s climate patterns • More heat and light per unit of surface area reach the tropics than the high latitudes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 52-10a Latitudinal Variation in Sunlight Intensity 90ºN (North Pole) 60ºN Low angle of incoming sunlight 30ºN 23.5ºN (Tropic of Cancer) Sun directly overhead at equinoxes 0º (equator) 23.5ºS (Tropic of Capricorn) 30ºS Low angle of incoming sunlight 60ºS 90ºS (South Pole) Atmosphere Seasonal Variation in Sunlight Intensity 60ºN 30ºN March equinox 0º (equator) June solstice 30ºS Constant tilt December solstice of 23.5º September equinox Fig. 52-10b 90ºN (North Pole) 60ºN Low angle of incoming sunlight 30ºN 23.5ºN (Tropic of Cancer) Sun directly overhead at equinoxes 0º (equator) 23.5ºS (Tropic of Capricorn) 30ºS Low angle of incoming sunlight 60ºS 90ºS (South Pole) Atmosphere • Seasonal variations of light and temperature increase steadily toward the poles Copyright
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