THE ECOLOGICAL PLANET : AN INTRODUCTION TO EARTH ’S MAJOR ECOSYSTEMS COURSE GUIDE Professor John Kricher WHEATON COLLEGE The Ecological Planet: An Introduction to Earth’s Major Ecosystems Professor John Kricher Wheaton College Recorded Books ™ is a trademark of Recorded Books, LLC. All rights reserved. The Ecological Planet: An Introduction to Earth’s Major Ecosystems Professor John Kricher Executive Producer John J. Alexander Executive Editor Donna F. Carnahan RECORDING Producer - David Markowitz Director - Matthew Cavnar COURSE GUIDE Editor - James Gallagher Design - Edward White Lecture content ©2008 by John Kricher Course guide ©2008 by Recorded Books, LLC 72008 by Recorded Books, LLC #UT119 ISBN: 978-1-4361-0596-5 All beliefs and opinions expressed in this audio/video program and accompanying course guide are those of the author and not of Recorded Books, LLC, or its employees. Course Syllabus The Ecological Planet: An Introduction to Earth’s Major Ecosystems About Your Professor/Introduction ............................................................................... 4 Lecture 1 Ecology and the Big Picture .................................................................. 6 Lecture 2 Earth and the Goldilocks Effect ........................................................... 10 Lecture 3 Distribution of Global Ecosystems ....................................................... 15 Lecture 4 Climate and Ecology ............................................................................ 19 Lecture 5 Biogeography and Evolution ................................................................ 23 Lecture 6 Polar Ecosystems and Tundra ............................................................ 28 Lecture 7 Boreal Forest ....................................................................................... 33 Lecture 8 Temperate Deciduous Forest .............................................................. 39 Lecture 9 Grassland and Savanna ...................................................................... 44 Lecture 10 Desert .................................................................................................. 50 Lecture 11 Tropical Rain Forest ............................................................................ 55 Lecture 12 Marine Ecosystems ............................................................................. 61 Lecture 13 Unique Coastal Ecosystems ................................................................ 67 Lecture 14 Current Issues in Global Ecology ........................................................ 75 Course Materials ........................................................................................................ 80 3 About Your Professor John Kricher John Kricher is a professor of biology at Wheaton College, Norton, Massachusetts. His books include r e Galapagos: A Natural History, A h c i r K Neotropical Companion, three ecology n h o J f field guides (Eastern Forests; Rocky o y s e t Mountain and Southwestern Forests; r u o c o and California and Pacific Northwest t o h P Forests), and First Guide to Dinosaurs . John is a fellow in the American Ornithologists Union and past-president of both the Association of Field Ornithologists and Wilson Ornithological Society. He resides with his wife Martha Vaughan on Cape Cod. Introduction Earth is the only known ecological planet, a place with life. But life is diverse: plants, animals, microbes, millions of species, many interacting in complex ways and all of them influenced in myriad ways by the environments in which they are found. Ecology is the study of organisms as they relate to their envi - ronments, the scientific study of natural history. But what does that really mean? It means that because of the many physical, chemical, and atmos - pheric characteristics of Earth, diverse forms of life have evolved throughout the history of the planet, life that is shaped and reshaped by both physical and biotic forces. Life is forced to evolve because of Earth’s diverse condi - tions and the fact that, over time, conditions change. Ecology is the search for broad general patterns evident in the distribution and abundance of life. Further, ecology attempts to explain such patterns with empirical reasoning. Ecology, a word taken from the Greek oikos , meaning home, is the same root as the word economics. Like economics it studies complex systems, in this case ecosystems. Ecology is the broadest level of organization in biology, the discipline that deals with interactions among populations, ecological commu - nities, and ecosystems. Earth is a planet with a complex climate, one that varies dramatically from equator to poles. As a consequence, life-forms adapted to polar regions are not well suited to equatorial areas and thus climate alone forces a high diver - sity to evolve among Earth’s numerous and variable organisms. Polar bears, for all their magnificent adaptations, are not adapted to survive in tropical conditions and the diverse array of trees comprising equatorial tropical rain forests would not long survive at higher latitudes. This course explores exactly why Earth supports life. It examines the various reasons why a small planet of about eight thousand miles diameter orbiting an average-sized star is uniquely suited to have a biosphere, a thin layer of living 4 matter surrounding its surface. Life abounds on both land and oceans but takes many different forms, mostly because climate is so variable. Beginning at the polar regions, the cold wind- swept Arctic and Antarctic, Professor Kricher will devote lectures to each of the Earth’s major ecosys - tems, called biomes. These include the vari - ous major forest types, m o c . the northern coniferous s o t o h (or boreal) forests that P surround the higher lati - © tudes like a vast belt of spruce and fir trees, the immense temperate decidu - ous forests of North America, Europe, and Asia, and the tropical rain forest, the ecosystem with more species than any other. When moisture is insufficient to support forest, other kinds of biomes occur. These include grassland, called prairie in North America, as well as savanna, a combination of grassland and scattered trees that typifies much of East Africa. The driest of all biomes is desert, which is always water stressed but may be hot or cold depending on where it is located. The largest ecosystems on Earth are marine, the oceans and coastal areas where land meets sea. The ocean realm has ecosystems that differ by depth. The open ocean or pelagic zone is where the food webs of the sea begin, where billions of tiny plants, the phytoplankton, capture some of the Sun’s energy and thus support all of the other creatures of the seas. But most of the ocean below about six hundred feet is cold and dark, and the benthic zone, or sea bottom, is lit only by the bioluminescence of the life-forms that inhabit it. Coastal ecosystems such as salt marsh, mangrove swamp, and coral reefs are among the most ecologically valuable as they are highly productive. At the same time, they are among the most threatened. The final lecture in the course will focus on how ecology has matured into a pragmatic science that is as essential as economics for making sound judg - ments about how best to steward the ecological planet. 5 Lecture 1: Ecology and the Big Picture The Suggested Reading for this lecture is John Kricher’s A Field Guide to Eastern Forests (chapters 1 and 2). m o c . s o t o h P © Wildflowers at the edge of a wooded field. cology is the scientific study of how life-forms interact and coexist. It is concerned not only with how living things adapt to each other, but also how they interact with and adapt to the nonliving compo - nents of the environment. Ecology is often defined simply as the study of organisms as they relate to their environments. Another definition is that ecology is the study of how various factors in the environment affect the distribution and abundance of organisms. Those “fac - tors” are divided into two broad categories, abiotic and biotic. Abiotic factors are such things as temperature, precipitation, phosphorus, oxygen, salinity, and fire. Biotic factors are interactions such as predation, parasitism and pathogens, competition for resources, and mutually beneficial interactions. Ecology is taken from the Greek word oikos , meaning “home,” the same root from which the word “economics” is derived. Both disciplines, ecology and economics, study how things relate within complex systems. Economists study the flow of money through economic systems as well as how materials move in the form of goods and services. Ecologists focus on energy flow E through ecosystems and study how atoms combine and recycle as life uses N O energy and material to maintain itself. The word “ecology” was coined in 1866 E by Ernst Haeckel. He was attempting to form a word describing the “economy R U of nature” that Charles Darwin described in his monumental book On the T C Origin of Species (1859). E L 6 Nothing in ecology makes sense without environmental context. For instance, you can watch a kangaroo in a zoo cage but you will not be observ - ing ecology. Kangaroos live in Australia, in open grassland and savanna habitats. To really learn about the ecology of a kangaroo, it is necessary to study the creature in the wild, in the Australian outback where groups of kan - garoos eat, groom, defend their territories, mate, and reproduce. So it is with all other animals and plants as well. Ecology looks at living things in the con - text