1. AN INTRODUCTION TO ECOLOGY AND THE BIOSPHERE
CHAPTER 50
AN INTRODUCTION TO ECOLOGY
AND THE BIOSPHERE

2. I. THE SCOPE OF ECOLOGY
ECOLOGY IS THE SCIENTIFIC STUDY OF THE INTERACTIONS BETWEEN ORGANISMS AND THEIR ENVIRONMENT
ECOLOGY USES OBSERVATIONS AND EXPERIMENTS TO TEST HYPOTHETICAL EXPLANATIONS OF THESE INTERACTIONS.
THE ENVIRONMENT INCLUDES BOTH ABIOTIC (NONLIVING) AND BIOTIC (LIVING) COMPONENTS.
ECOLOGICAL INTERACTIONS AFFECT HOW ORGANISMS EVOLVE, AND EVOLUTIONARY CHANGE IN TURN AFFECTS ECOLOGICAL RELATIONSHIPS.

3. II. ABIOTIC FACTORS OF THE BIOSPHERE
A. CLIMATE AND OTHER ABIOTIC FACTORS ARE IMPORTANT DETERMINANTS OF THE BIOSPHERE'S DISTRIBUTION OF ORGANISMS
THE BIOSPHERE IS AN ENVIRONMENTAL MOSAIC IN WHICH SEVERAL ABIOTIC FACTORS AFFECT THE DISTRIBUTION AND ABUNDANCE OF ORGANISMS: TEMP. , WATER QUALITYAND AVAILABILITY, LIGHT INTENSITY, WIND, SOIL CHARACTERISTICS, AND LESS PREDICTABLE DISTURBANCES SUCH AS FIRE.

5. GLOBAL CLIMATES AND SEASONALITY ARE ESTABLISHED BY THE INPUT OF SOLAR ENERGY AND EARTH’S ROTATION AROUND THE SUN

6. LATITUDINAL VARIATION IN TEMP
LATITUDINAL VARIATION IN TEMP. AND PRECIPITATION ACCOUNT FOR THE GEOGRAPHICAL DISTRIBUTION OF MAJOR ECOSYSTEMS.

7. OCEANS AND LAKES MODERATE THE CLIMATE IN COASTAL LOCALITIES, AND MOUNTAINS INFLUENCE TEMPERATURE AND RAINFALL.

8. III. AQUATIC AND TERRESTRIAL BIOMES
A. AQUATIC BIOMES OCCUPY THE LARGEST PART OF THE BIOSPHERE
OCEANS, COVERING NEARLY 75% OF EARTH'S SURFACE, HAVE A MAJOR EFFECT ON CLIMATE, AND MARINE ORGANISMS SUPPLY A SUBSTANTIAL PART OF THE WORLD'S OXYGEN (02)
FRESHWATER ARE CLOSELY LINKED TO THEIR SURROUNDING TERRESTRIAL BIOMES.
AQUATIC BIOMES ARE OFTEN STRATIFIED VERTICALLY WITH REGARD TO LIGHT PENETRATION, TEMPERATURE, AND COMMUNITY STRUCTURE.
EUTROPHIC LAKES ARE HIGH IN NUTRIENTS AND PRODUCTIVITY, AND OLIGOTROPHIC LAKES ARE NUTRIENT POOR.

9. RUNOFF FROM SURROUNDING LAND TRANSFORMS OLIGOTROPHIC LAKES INTO EUTROPHIC LAKES.
RIVERS AND STREAMS CONTAIN FRESHWATER COMMUNITIES THAT CHANGE SIGNIFICANTLY FROM THE SOURCE TO THE FINAL DESTINATION IN AN OCEAN OR LAKE.
WETLANDS HAVE SOIL RANGING FROM PERIODICALLY FLOODED TO PERMANENTLY SATURATED.
WET LANDS ARE BIOLOGICALLY DIVERSE, CONTAINING SPECIALLY ADAPTED PLANTS CALLED HYDROPHYTES, WHICH CAN GROW IN WATER OR SOIL THAT IS PERIODICALLY ANAEROBIC.
AN ESTUARY IS THE ZONE OF MARKED FLUCTUATIONS IN SALINITY WHERE A RIVER OR STREAM ENTERS THE OCEAN.
OCEANIC ZONES, CLASSIFIED ACCORDING TO DEPTH, LIGHT PENETRATION, DISTANCE FROM THE SHORE, AND OPEN WATER VS. BOTTOM, INCLUDE THE INTERTIDAL ZONE, THE NERITIC ZONE, AND THE OCEANIC ZONE.

10. IN THE TROPICS, CORAL REEFS ARE FOUND IN THE WARM, NUTRIENT-RICH WATERS OF THE NERITIC ZONE.
THE OCEANIC PELAGIC BIOME INCLUDES MOST OF THE OPEN OCEAN.
PHOTOSYNTHETIC PLANKTON IN THE PHOTIC REGION OF THE PELAGIC ZONE ARE THE PRIMARY FOOD SOURCE FOR THE REST OF THE COMMUNITY.
BENTHIC, OR BOTTOM, COMMUNITIES SUBSIST LARGELY ON DETRITUS THAT RAINS DOWN FROM THE PELAGIC ZONE.

12. A.    THE GEOGRAPHICAL DISTRIBUTION OF TERRESTRIAL BIOMES IS BASED MAINLY ON REGIONAL VARIATIONS IN CLIMATE
NEAR THE EQUATOR, WHERE PHOTOPERIOD AND TEMPERATURE ARE NEARTLY CONSTANT, THE AMOUNT AND PATTERN OF RAINFALL DETERMINES BIOMES, INCLUDING TROPICAL RAIN FOREST AND SAVANNA.
DESERTS ARE INHABITED BY PLANTS AND ANIMALS ADAPTED TO EXTREMELY DRY CONDITIONS.
CHAPARRAL IS A DRY SCRUBLAND FOUND WHERE WINTERS ARE MILD AND SUMMERS ARE HOT AND DRY.
TEMPERATE GRASSLANDS OCCUR ON NUTRIENT-RICH, DEEP SOILS WHERE PERIODIC FIRES AND DROUGHT AND THE GRAZING OF LARGE MAMMALS INHIBIT THE GROWTH OF WOODY PLANTS.

13. TEMPERATE DECIDUOUS FORESTS OCCUR IN MIDLATITUDES WHERE THERE IS SUFFICIENT MOISTURE TO SUPPORT THE GROWTH OF LARGE, BROAD LEAFED DECIDUOUS TREES.
CONIFEROUS FORESTS INCLUDE COASTAL TEMPERATE RAIN FORESTS AND THE NORTHERN CONIFEROUS FOREST, OR TAIGA.
ARCTIC TUNDRA OCCURS AT THE NORTHERNMOST LIMITS OF PLANT GROWTH, WHERE COLD TEMPERATURES, WIND, AND PERMAFROST LIMIT PLANTS TO LOW SHRUBBV OR MATLIKE FORMS.
ALPINE TUNDRA OCCURS AT HIGH ALTITUDES.

15. IV. CONCEPTS OF ORGANISMAL ECOLOGY
A. THE COSTS AND BENEFITS OF HOMEOSTASIS AFFECT AN ORGANISM'S RESPONSES TO ENVIRONMENTAL VARIATION
AN ORGANISM'S ADAPTATIONS TO ITS ENVIRONMENT REPRESENT A SET OF EVOLUTIONARY COMPROMISES.

16. B. AN ORGANISM'S SHORT-TERM RESPONSES TO ENVIRONMENTAL VARIATIONS OPERATE WITHIN A LONG-TERM EVOLUTIONARY FRAMEWORK
THE RELATIONSHIP BETWEEN AN ORGANISM AND ITS ENVIRONMENT INVOLVES BOTH SHORT-TERM RESPONSE MECHANISMS AND THE LONG-TERM EVOLUTIONARY FRAMEWORK IN WHICH SHORT-TERM RESPONSES OPERATE.