Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 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 Chapter 52 An Introduction to Ecology and the Biosphere

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Learning Targets: 1.Explain how dispersal may contribute to a species’ distribution 2.Distinguish between: potential and actual range, biotic and abiotic factors, macroclimate and microclimate patterns 3.Explain how a body of water or mountain range might affect regional climatic conditions

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 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 Ecologists work at levels ranging from individual organisms to the planet

Scopes of Ecology Organismal ecology Population ecology Community ecology Ecosystem ecology Landscape ecology Global ecology

Rachel Carson

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 1 st Earth day April 22, 1970 Gaylord Nelson, Wisconsin Senator Environmentalism History

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 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

Kangaroos/km 2 0– –1 1–5 5–10 10–20 > 20 Limits of distribution

Why is species X absent from an area? Does dispersal limit its distribution? Does behavior limit its distribution? Area inaccessible or insufficient time Yes No Yes Habitat selection Do biotic factors (other species) limit its distribution? Predation, parasitism, competition, disease Do abiotic factors limit its distribution? Chemical factors Physical factors Water Oxygen Salinity pH Soil nutrients, etc. Temperature Light Soil structure Fire Moisture, etc. Ecologists consider multiple factors when attempting to explain the distribution of species Interactions between organisms and the environment limit the distribution of species

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 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 Natural range expansions show the influence of dispersal on distribution

Current

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 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 Exotic species in Wisconsin

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

Sea urchin Limpet Seaweed cover (%) Both limpets and urchins removed Only urchins removed Only limpets removed Control (both urchins and limpets present) August 1982 August 1983 February 1983 February 1984 Does feeding by sea urchins limit seaweed distribution?

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Abiotic Factors Abiotic factors affecting distribution of organisms include: 1.Temperature 2.Water 3.Sunlight 4.Wind 5.Rocks and soil Most abiotic factors vary in space and time

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 Seasonal variations of light and temperature increase steadily toward the poles

Latitudinal Variation in Sunlight Intensity Low angle of incoming sunlight Sun directly overhead at equinoxes Low angle of incoming sunlight Atmosphere 90ºS (South Pole) 60ºS 30ºS 23.5ºS (Tropic of Capricorn) 0º (equator) 30ºN 23.5ºN (Tropic of Cancer) 60ºN 90ºN (North Pole) Seasonal Variation in Sunlight Intensity 60ºN 30ºN 30ºS 0º (equator) March equinox June solstice Constant tilt of 23.5º September equinox December solstice

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Global air circulation and precipitation patterns play major roles in determining climate patterns Warm wet air flows from the tropics toward the poles Air flowing close to Earth’s surface creates predictable global wind patterns Cooling trade winds blow from east to west in the tropics; prevailing westerlies blow from west to east in the temperate zones

Global Air Circulation and Precipitation Patterns 60ºN 30ºN 0º (equator) 30ºS 60ºS Global Wind Patterns Descending dry air absorbs moisture Ascending moist air releases moisture Descending dry air absorbs moisture Arid zone Tropics Arid zone 0º 66.5ºN (Arctic Circle) 60ºN 30ºN 0º (equator) 30ºS 60ºS 66.5ºS (Antarctic Circle) Westerlies Northeast trades Doldrums Southeast trades Westerlies 23.5º 30º 23.5º 30º

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Regional, Local, and Seasonal Effects on Climate Proximity to bodies of water and topographic features contribute to local variations in climate Seasonal variation also influences climate Microclimate along Lake Michigan The Gulf Stream carries warm water from the equator to the North Atlantic Oceans and their currents and large lakes moderate the climate of nearby terrestrial environments

Labrador current Gulf stream Equator Cold water Warm water Bodies of Water

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings During the day, air rises over warm land and draws a cool breeze from the water across the land As the land cools at night, air rises over the warmer water and draws cooler air from land back over the water, which is replaced by warm air from offshore Bodies of Water

Warm air over land rises Air cools at high elevation. Cool air over water moves inland, replacing rising warm air over land. Cooler air sinks over water.

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Mountains have a significant effect on – The amount of sunlight reaching an area – Local temperature – Rainfall Rising air releases moisture on the windward side of a peak and creates a “rain shadow” as it absorbs moisture on the leeward side Mountains

Wind direction Mountain range Leeward side of mountain Ocean Mountains

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The angle of the sun leads to many seasonal changes in local environments Lakes are sensitive to seasonal temperature change and experience seasonal turnover Seasonality

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Microclimate Microclimate is determined by fine-scale differences in the environment that affect light and wind patterns

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Long-Term Climate Change Global climate change will profoundly affect the biosphere One way to predict future global climate change is to study previous changes As glaciers began retreating 16,000 years ago, tree distribution patterns changed As climate changes, species that have difficulty dispersing may have smaller ranges or could become extinct