Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Biology Concepts and Applications | 9e Starr | Evers | Starr Chapter 43 The Biosphere © Cengage Learning 2015 © Cengage Learning 2015 43.1 What Determines Air Circulation Patterns? • Climate – The average weather conditions (cloud cover, temperature, humidity, wind speed) over time – Regional climates are influenced by factors that affect winds and ocean currents (intensity of sunlight, distribution of land masses and seas, and elevation) © Cengage Learning 2015 43.3 What Are the Major Biomes? • Biomes – Communities with similar climates and vegetation – Evolve in widely separated regions as a result of similar environmental factors – Discontinuous region characterized by its climate and dominant vegetation © Cengage Learning 2015 What Are the Major Biomes? © Cengage Learning 2015 What Are the Major Biomes? • Differences between biomes – Rainfall and temperature are the main determinants of the type of biome in a given region – Soils also influence biome distribution • Properties of soils vary depending on the types, proportions, and compaction of mineral particles and varying amounts of humus – Climate and soils affect primary production, so primary production varies among biomes © Cengage Learning 2015 43.4 What is the Most Productive Biome? • Tropical rainforests – Form between latitudes 10° north and south in Africa, East Indies, Asia, and South and Central America – 130 to 200 centimeters (50 to 80 inches) of rain falls throughout the year – Highly productive and species-rich biome in which year-round rains and warmth support continuous growth of evergreen broadleaf trees © Cengage Learning 2015 What is the Most Productive Biome? • Tropical rain forest is the most productive, structurally complex, and species-rich biome – Photosynthesis occurs year-round, but trees often form a closed canopy that blocks light from the forest floor – Deforestation is an ongoing threat to tropical rain forests in developing countries with fastgrowing human populations © Cengage Learning 2015 What is the Most Productive Biome? O horizon: Sparse litter A–E horizons: Continually leached; iron, aluminum left behind impart red color to acidic soil B horizon: Clays with silicates, other residues of weathering © Cengage Learning 2015 43.5 What Types of Forests Occur in Cooler Climates? • Temperate deciduous forests – Northern Hemisphere biome in which the main plants are broadleaf trees that lose their leaves in fall and become dormant during cold winters – Deciduous plant sheds leaves annually, prior to a season when cold or dry conditions would not favor growth © Cengage Learning 2015 What Types of Forests Occur in Cooler Climates? • Temperate deciduous forests – Form where 50 to 150 centimeters (20–60 inches) of precipitation falls throughout the year – Winters are cool and summers are warm – Leaves often turn color before dropping in autumn – Trees remain dormant in winter; flower and put out new leaves in spring © Cengage Learning 2015 What Types of Forests Occur in Cooler Climates? • Coniferous forests – Conifers withstand harsher conditions than broadleaf trees, so they grow farther north and at higher altitudes – The coniferous forest that extends across northern Asia, Europe, and North America – known as the boreal forest or taiga – is the most extensive land biome © Cengage Learning 2015 What Types of Forests Occur in Cooler Climates? • Coniferous forests – Conifers (evergreen trees with seed-bearing cones) such as pine, fir, and spruce are the main plants in coniferous forests – Conifers are adapted to conserve water during drought or times when the ground is frozen • Winters are long, cold, and dry; and most rain falls in the cool summer – Moose are the dominant grazers © Cengage Learning 2015 What Types of Forests Occur in Cooler Climates? A North American temperate deciduous forest in fall. B Boreal forest (taiga) in Siberia. © Cengage Learning 2015 43.6 What Are the Fire-Adapted Biomes? • Grasslands – Form in the interior of continents between deserts and temperate forests – Perennial grasses adapted to fire, grazing, strong winds, and infrequent rain are the main plants in grasslands – Temperate grasslands are warm in summer, cold in winter, with rains throughout the year – Grass roots help hold thick topsoil in place, preventing erosion by constant winds © Cengage Learning 2015 What Are the Fire-Adapted Biomes? A B © Cengage Learning 2015 43.7 What Is the Driest Biome? • Deserts – Tend to have low humidity, large daily temperature shifts, and little topsoil – Receive less than 10 centimeters (4 inches) of rain per year – Most are located at about 30° north and south latitude, or in rain shadows – Plants that have water-storing and conserving adaptations predominate © Cengage Learning 2015 What Is the Driest Biome? • Deserts – Diversity is highest in regions where moisture is available in more than one season – CAM plants (cactuses, agaves, euphorbs) conserve water by opening stomata only at night when temperature declines – Annuals have a life cycle that allows them to sprout and reproduce in the short time that the soil is moist © Cengage Learning 2015 What Is the Driest Biome? © Cengage Learning 2015 43.8 What Is the Coldest Biome? • Arctic tundra – Highest-latitude Northern biome – Low, cold-tolerant plants survive with only a brief growing period – Forms between the polar ice cap and belts of boreal forests in the Northern Hemisphere – Snow covers arctic tundra up to nine months of the year © Cengage Learning 2015 What Is the Coldest Biome? • Arctic tundra – Only the surface layer of soil thaws during summer – below that lies permafrost up to 500 meters (1,600 feet) thick – Permafrost • Prevents drainage • Cool and anaerobic conditions slow decay • Organic remains build up © Cengage Learning 2015 What Is the Coldest Biome? © Cengage Learning 2015 43.9 What Are the Main Types of Freshwater Ecosystems? • Freshwater ecosystems – Gradients in light penetration, temperature, and dissolved gases affect the distribution of life in aquatic habitats – Include lakes, streams, and rivers © Cengage Learning 2015 What Are the Main Types of Freshwater Ecosystems? © Cengage Learning 2015 What Are the Main Types of Freshwater Ecosystems? • Dissolved oxygen – One of the most important factors affecting aquatic organisms • More oxygen dissolves in cooler, fast-flowing water than in warmer, still water • When water temperature increases or water becomes stagnant, aquatic species with high oxygen needs suffocate • Smoothly flowing water, holds less oxygen than water that mixes with air as it runs over rocks © Cengage Learning 2015 43.10 What Are Coastal Ecosystems? • Near the coasts of continents and islands, concentrations of nutrients support highly productive aquatic ecosystems • Estuary: an enclosed coastal region where seawater mixes with fresh water from rivers and streams – A highly productive ecosystem where nutrientrich water from a river mixes with seawater © Cengage Learning 2015 What Are Coastal Ecosystems? • Estuaries – Marine nurseries; many larval and juvenile invertebrates and fishes live in them – Detrital food chains predominate – Primary producers include algae and other phytoplankton, along with plants that tolerate submergence at high tide © Cengage Learning 2015 What Are Coastal Ecosystems? A Cordgrass (Spartina) in a South Carolina salt marsh. Salt taken up in water by roots is excreted by glands on the leaves. B Mangroves along the shore in Florida. Specialized cells at the surface of some exposed prop roots allow gas exchange with air. © Cengage Learning 2015 43.11 What are Coral Reefs? • Coral reefs: highly diverse marine ecosystem – Wave-resistant formations that consist primarily of calcium carbonate secreted by coral polyps • Reef-forming corals live mainly in shallow, clear, warm waters between latitudes 25° north and 25° south – A healthy reef is home to living corals and a quarter of all marine fish species © Cengage Learning 2015 What Are Coral Reefs? © Cengage Learning 2015 What Are Coral Reefs? © Cengage Learning 2015 Biology Concepts and Applications | 9e Starr | Evers | Starr Chapter 44 Human Effects on the Biosphere © Cengage Learning 2015 © Cengage Learning 2015 44.1 Why Are So Many Species Threatened of Endangered? • All over the world, humans are replacing wildlife habitat with our dwellings, factories, and farms • We also put species at risk – Competing with them for resources – Overharvesting them – Introducing non-native competitors • The rate of species extinctions is rising; many types of biomes are threatened © Cengage Learning 2015 Why Are So Many Species Threatened of Endangered? • A species is considered endangered when one or more of its populations have declined or are declining – Endangered species • A species that faces extinction in all or a part of its range – Threatened species • Species likely to become endangered in the near future © Cengage Learning 2015 What Are the Effects of Desertification and Deforestation? A Dust cloud in the Great Plains during the 1930s. © Cengage Learning 2015 B Dust blows across the Atlantic from North Africa. What Are the Effects of Desertification and Deforestation? • Tropical forests continue to disappear at an alarming rate • In addition to immediate destruction of forest organisms, deforestation encourages flooding, and raises risk of landslides in hilly areas • Deforestation also affects local weather – temperatures rise, and reduced transpiration results in less rainfall © Cengage Learning 2015 What Are the Effects of Desertification and Deforestation? • Forests take up and store huge amounts of carbon, so deforestation also contributes to global climate change – Deforested areas also become nutrient-poor • Experimental deforestation increased runoff of essential soil nutrients such as calcium (compared with undisturbed forest) © Cengage Learning 2015 What Are the Effects of Desertification and Deforestation? © Cengage Learning 2015 44.3 How Does Trash Degrade Habitats? • Trash: – Buried in the ground (such as lead from batteries) can contaminate groundwater – Dumped at sea (such as plastics) harms marine life • Plastic and other garbage that enters our coastal waters persists for many years – Avoid buying plastics, or be sure to recycle or dispose of them properly © Cengage Learning 2015 How Does Trash Degrade Habitats? A © Cengage Learning 2015 B 44.4 What Are the Effects of Acid Rain? • Pollutants disrupt physiological processes of organisms – Sulfur dioxides from coal-burning power plants, and nitrogen oxides from burning gas and oil, are common air pollutants – Pollutant • Substance that is released into the environment by human activities and interferes with the function of organisms that evolved in the absence of the substance or with lower levels © Cengage Learning 2015 What Are the Effects of Acid Rain? • Dry acid deposition: dry dust particles coated with airborne sulfur and nitrogen • Wet acid deposition (acid rain): pollutants combine with water and fall as acidic precipitation • Acid rain – Low pH rain that forms when sulfur dioxide and nitrogen oxides mix with water vapor in the atmosphere © Cengage Learning 2015 What Are the Effects of Acid Rain? • Acid rain in aquatic habitats – Prevents fish eggs from developing – Kills adult fish • Acid rain in forests – Burns tree leaves – Makes trees more susceptible to insects and pathogens © Cengage Learning 2015 44.5 What Are the Effects of Ozone Depletion and Pollution? • Ozone is said to be “good up high, but bad nearby” – In the upper atmosphere, the ozone (O3) layer absorbs most incoming ultraviolet (UV) radiation that damages DNA and causes mutations – Near the ground, it is a harmful pollutant © Cengage Learning 2015 What Are the Effects of Ozone Depletion and Pollution? • In the mid-1970s, scientists noticed that Earth’s ozone layer (10.5 to 17 miles above sea level) was thinning, particularly over Antarctica (the “ozone hole”) • In 1987, countries worldwide agreed to phase out production of chlorofluorocarbons (CFCs) and other ozone-destroying chemicals – but existing CFCs break down very slowly © Cengage Learning 2015 44.6 What Are the Effects of Global Climate Change? • Climate change is the most widespread threat to habitats worldwide – Thermal expansion/meltwater from glaciers flood coastal wetlands – Temperature changes disrupt life-cycle events (e.g., tree flowering, animal migration, and breeding seasons) – Some species are moving to higher latitudes or elevations; those that cannot move are stressed or dying © Cengage Learning 2015 What Are the Effects of Global Climate Change? • Many weather patterns are expected to change as rising land and sea temperatures affect evaporation, winds, and currents • Examples – Extremes in rainfall patterns: periods of drought interrupted by unusually heavy rains – Increase in hurricane intensity © Cengage Learning 2015 What Are the Effects of Global Climate Change? Muir Glacier in Alaska (1940) Muir Glacier in Alaska (2004) © Cengage Learning 2015 What Is Conservation Biology? • Healthy ecosystems are essential to human survival: – Produce our oxygen and food – Remove, decompose, and detoxify wastes – Prevent erosion and reduce risk of flooding – Allow for new medicines to be derived from compounds in wild species – Encourage plant breeders to use genes in wild species to protect and improve crops © Cengage Learning 2015 What Is Conservation Biology? • People often oppose environmental protections because they fear adverse economic consequences • Conservation biologists help determine which regions should be targeted for protection first by identifying hot spots – Threatened region with great biodiversity that is considered a high priority for conservation efforts © Cengage Learning 2015 What Is Conservation Biology? © Cengage Learning 2015 44.8 How Can We Reduce Our Impact? • Ultimately, the health of our planet depends on our ability to recognize the principles of energy flow and resource limitation • The goal is living sustainably – Meeting the needs of the present generation without reducing the ability of future generations to meet their own needs © Cengage Learning 2015 How Can We Reduce Our Impact? • People in industrial nations use enormous quantities of resources, and the extraction, delivery, and use of these resources has negative effects on biodiversity – Example: In the U.S., an average new home contains about 500 pounds of copper wiring and plumbing • Strips vegetation and soil; produces waste; causes air and water pollution © Cengage Learning 2015 How Can We Reduce Our Impact? A © Cengage Learning 2015 B Ecological Footprint © Cengage Learning 2015 © Cengage Learning 2015 © Cengage Learning 2015 Figure 19.22 44.9 A Long Reach • In the Arctic, unusually warm temperatures are affecting the seasonal cycle of sea ice melting and formation – Polar bears can only reach their main prey by traveling across ice • Other threats – high amounts of mercury and organic pesticides are carried to polar regions by winds and ocean currents – Have been found in tissues of polar bears © Cengage Learning 2015 A Long Reach • Eight countries, including the U.S., control parts of the Arctic and have rights to extensive oil, gas, and mineral deposits – Melting ice sheets make it easier to remove minerals and fossil fuels from the Arctic – Extracting these resources will further harm Arctic species that are already threatened by global climate change © Cengage Learning 2015 © Cengage Learning 2015 11/26 Friday Schedule Populations 40 11/28 No Class 12/3 41 12/5 Trophic Levels Ecology Succession Lab Review 12/10 Biomes & Human 43&44 12/12 Effect Lecture Review Lab Final Exam 12/17 Make up class if needed Final Exam © Cengage Learning 2015 12/19 42