Transcript Chapter 15
Chapters 21 and 22 Ecosystems Humans and the Environment The Biosphere • The biosphere is the part of the earth where life exists – The hydrosphere is all of Earth’s ice, water and vapor – The atmosphere is the air blanketing Earth’s solid and liquid surfaces – The geosphere includes all of the features of Earth’s surface (continents, rocks and seafloor) and everything below Earth’s surface The Biosphere (cont’d) • Biotic and abiotic factors interact and affect on another in the biosphere – The Gaia Hypothesis proposes that Earth is a kind of living organism in which the hydrosphere, geosphere, biosphere and atmosphere are interacting systems that maintain one another’s balances. • Examples: deforestation leads to erosion, surplus of CO2 spurs plant growth How does climate affect you? • What crops do we grow in this area of the country? • Do you think other crops would do as well here? Why or why not? Weather vs. Climate • Weather – the day to day condition of earth’s atmosphere at a particular time and place • Climate – the average year after year conditions based on temperature and precipitation in a particular region • What affect does the sun have on weather? • What affect does topography have on climate? Climate and Microclimate • Microclimate is a small area within a climate that differs significantly in temperature, rainfall totals, etc. • Examples: near Ohio River, Whidbey Island, rooftop gardens The Influence of Sunlight The Greenhouse Effect • What happens to the inside of a car on a hot day? • The sun unevenly heats the earth’s atmosphere and affects wind and water currents around the globe Other Factors that Shape Climate • Air and water movement, which responds to the uneven heating of Earth’s surface by the sun • Landmasses such as mountain ranges Major Biomes pg 463 • • • • • • • • • • Tropical Rain Forest Tropical Dry Forest Tropical Savannah Desert Temperate Grassland Temperate Woodland and Shrubland Temperate Forest Northwestern Coniferous Forest Boreal Forest (Taiga) Tundra What Makes a Biome? Biome Map of North America Aquatic Ecosystems • Important components of aquatic ecosystems are temperature, depth, flow and water chemistry • Three types: – Freshwater – Marine – Estuary Aquatic Ecosystems of the US Freshwater Ecosystems • Include the Great Lakes, Lake Champlain, Lake Cumberland, Ohio River, the Everglades • Three types: – Flowing water – Standing water • Characterized by the presence of plankton and phytoplankton – Wetlands Estuaries • • • • • • Wetlands formed where rivers meet the sea Contain a mixture of fresh and salt water Detritus is a major player in estuaries Serve as breeding grounds Important migratory stops Examples: Mangrove swamps and salt marshes Marine Ecosystems • • • • • • Photic zone vs Aphotic zone Intertidal zone Coastal Zone Coral Reefs Open Ocean Benthic Zone Intertidal zone Oceanic Zones Changing the Landscape • Everywhere humans have traveled, they have changed the landscape to suit their needs – Introducing invasive species – Overusing resources • How are some of the ways in which we have changed Earth’s layers (biosphere, geosphere, atmosphere, hydrosphere)? Scientists are Worried… • …that the gigantic impact we have on this planet may harm Earth’s biodiversity. • So we measure it: – Species Richness – Population Evenness • MiniLab (in table groups, max 4): – Count the number of colors of gummy bears you have (richness) – Count the number of each color you have (evenness) The Value of Biodiversity • Biodiversity is on of Earth’s greatest natural resources • Ecosystem diversity refers to the variety of habitats and communities in the biosphere • Species diversity refers to the number of different species in the biosphere • Genetic diversity refers to the sum total of all genetic info on Earth Threats to Biodiversity • Human activity can reduce biodiversity by altering habitats and eliminating species through extinction • Habitat Fragmentation is something that takes place when human activities split up habitats, isolating populations • Non-sustainable hunting practices can lead to extinction of some species • Invasive species introduction can lead to extinction of plants and animals Pollution and Biomagnification • While all forms of pollution pose a threat to the planet, introduction of toxic chemicals into the environment is the most dangerous • Examples include arsenic, lead and mercury, along with 272 others listed by the CDC • An historical example includes DDT and how it harmed birds at the top of the food chain without direct application to the animal Ozone Thinning and Acid Rain • Ozone thinning leads to more UV rays reaching Earth’s surface. CFCs are a big contributor to ozone thinning. • Acid Rain is caused by industrial pollution and raises the pH of rain water. This will damage plant life and change biodiversity in large swaths of the planet. Renewable and Nonrenewable Resources • Renewable Resource – can regenerate quickly and are replaceable • Examples: • Nonrenewable Resource – Either will not regenerate or will take eons to regenerate • Examples: Sustainable Use • Sustainable Use is a way of using natural resources that does not deplete them • These industries work to sustainably use resources daily: – Fisheries – Agriculture – Land Developers Top 5 Resources • Renewable or Nonrenewable? – Land – Forest – Ocean – Air – Freshwater Conservation of Biodiversity • By protecting habitats for wildlife, we are conserving biodiversity • Other techniques include zoo-based breeding programs that rescue animals or breed them in captivity and then return them to the wild • Conservation takes place on land as well as in marine environments • Conservation challenges include political pressures, financial pressures and balance between human and wild needs Conservation Biology • Conservation biologists work to try to protect biodiversity in areas that are threatened. • Restoration biologists work to restore damaged ecosystems. • Ecotourism is a form of tourism that supports conservation and brings economic benefit to local people.