Chapter 42 Ecosystems

42.1 How Do Energy and Nutrients Move Through An Ecosystem? Ecosystems A ____________ of organisms together with the nonliving components of their environment Organisms and their environment interact through a __________ flow of _________ and a _______________________. Nutrients taken up by ____________ are returned to the environment by ________________, then taken up again

How Do Energy and Nutrients Move Through An Ecosystem? (cont’d.) An ecosystem runs on energy captured by ______________________ Primary producer (_____________) An organism that obtains energy and nutrients from _____________________ to build organic compounds Primary production Rate at which producers capture and store energy Varies by ecosystem, season, and ______________________

How Do Energy and Nutrients Move Through An Ecosystem? (cont’d.) Consumers are described by their diets Herbivores (_____________) Carnivores (___________________) Parasites (__________________________) Omnivores (_________________________) Detritivores (_________________) Decomposers (______________________)

ANIMATION: One-way energy flow and materials cycling Figure 42.1 {Animated} One-way flow of energy (yellow arrows) and nutrient cycling (blue arrows) in the most common type of ecosystem. All light energy that enters the system eventually returns to the environment as heat energy that is not reused. By contrast, nutrients are continually recycled. To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

How Do Energy and Nutrients Move Through An Ecosystem? (cont’d.) Food chains Describe how energy and materials are ___________ from one organism to another Description of __________________ in one _____________________ in an ecosystem Transfer of energy to _________________ levels Trophic level: ______________ of an ________________ in a food chain

How Do Energy and Nutrients Move Through An Ecosystem? (cont’d.) Limits of food chains Energy captured by producers usually passes through __________________ four or five trophic levels The length of food chains is _____________ by the ________________ of energy transfers Only 5-30% of energy in an organism at one trophic level ends up in _____________ of an organism at the next trophic level

3D Animation: Food Chain Figure 42.2 {Animated} Food chain. An example of who eats whom in a tall grass prairie ecosystem in Kansas. Yellow arrows indicate energy flow. Plants are the main producers. Sunlight energy they capture and store in their tissues supplies the energy that the ecosystem’s consumers require.

42.2 How Do Food Chains Interconnect? Food chains of an __________________ as a food web The food web diagram reflects _________________ constraints and the inefficiency of energy transfers among trophic levels

ANIMATION: Rainforest food web Figure 42.3 {Animated} Some organisms in an arctic food web. Yellow arrows indicate path of energy flow (point from eaten to eater). To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

How Do Food Chains Interconnect (cont’d.) Food webs include two types of interconnecting food chains _______________ food chain Energy transferred from producers to herbivores (______________) Energy transferred directly from producers to detritivores (_______________________) Major food chain in land ecosystems

42.3 What Are Ecological Pyramids? Ecological pyramid diagrams illustrate the inefficiency of transfers between trophic levels A _____________________ shows amounts of ________________________in bodies of organisms at each trophic level at a specific time An __________ pyramid shows energy flow through each trophic level in a given interval

What Are Ecological Pyramids? (cont’d.) Figure 42.4 Computer model for a land food web in East River Valley, Colorado. Balls signify species. Their colors identify trophic levels, with producers (coded red) at the bottom and top predators ( yellow) at top. The connecting lines thicken as they go from an eaten species to the eater.

ANIMATION: Energy flow at Silver Springs Figure 42.5 {Animated} Ecological pyramids for Silver Springs, an aquatic ecosystem in Florida. To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

42.4 Biogeochemical Cycles ___________ essential to life move between a ______________ and its environment in a biogeochemical cycle A nutrient moves between environmental ______________ and in and out of food webs Chemical and _____________ processes move elements to, from, and among environmental reservoirs (rocks, sediments, water, atmosphere)

Biogeochemical Cycles (cont’d.) Figure 42.6 Generalized biogeochemical cycle. For any nutrient, the cumulative amount in all environmental reservoirs far exceeds the amount in living organisms.

42.5 What Is the Water Cycle? Ninety-seven percent of Earth’s water is in its oceans Sunlight energy drives the water cycle by causing ______________ Water vapor in the atmosphere _______________ into clouds, and returns to Earth’s surface as ______________

ANIMATION: Hydrologic cycle Figure 42.7 {Animated} The water cycle. Water moves from the ocean to the atmosphere, land, and back. The arrows identify processes that move water. To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

What Is the Water Cycle? (cont’d.) How water moves Precipitation that falls on any specific area of land drains into its particular _____________ Most precipitation seeps into the ground (groundwater) Water that drains through soil layers often collects in natural underground reservoirs (______________) The flow of groundwater and surface water (___________) slowly returns water to oceans

What Is the Water Cycle? (cont’d.) Table 42.1 Environmental water resources

42.6 How Does Carbon Move Through Ecosystems? Carbon cycle An ______________ cycle Most carbon is stored in rocks Enters food webs as ___________ carbon dioxide or bicarbonate dissolved in water Movement is mainly between the oceans, atmosphere, and living organisms

How Does Carbon Move Through Ecosystems? (cont’d.) Steps in the carbon cycle Carbon enters land food webs when plants use _______ from the air in photosynthesis CO2 released by _________________ returns to the atmosphere Carbon diffuses between ______________ and _____________ ____________ forms when CO2 dissolves in seawater

How Does Carbon Move Through Ecosystems? (cont’d.) ___________ producers take up bicarbonate for photosynthesis; marine organisms release CO2 from aerobic respiration Many marine organisms incorporate carbon into shells, which become part of sediments Sediments become limestone and chalk in Earth’s crust Burning ________________ derived from ancient remains of plants puts additional CO2 into the atmosphere

ANIMATION: Carbon cycle Figure 42.8 {Animated} The carbon cycle To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

How Does Carbon Move Through Ecosystems? (cont’d.) Greenhouse effect Warming of Earth’s lower atmosphere and surface as a result of heat _____________ by greenhouse gases

How Does Carbon Move Through Ecosystems? (cont’d.) Earth’s atmosphere ____________ some sunlight energy back into space Some light energy reaches and warms Earth’s surface Earth’s warmed surface ____________ heat energy Some __________________________ Some is _________________________ in all directions by greenhouse gases

How Does Carbon Move Through Ecosystems? (cont’d.) _________________ increase in atmospheric greenhouse gases correlates with global climate change Current atmospheric CO2 is the highest in 420,000 years–and is still climbing Global climate change A rise in temperature and shifts in other climate patterns

ANIMATION: The Greenhouse Effect Figure 42.9 {Animated} The Greenhouse Effect To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

42.7 How Does Nitrogen Move Through Ecosystems? Nitrogen cycle An atmospheric cycle Atmospheric nitrogen (________________) is Earth’s main nitrogen reservoir, but most organisms can’t use N2

42.7 How Does Nitrogen Move Through Ecosystems? Certain bacteria can make nitrogen available to other organisms/atmosphere With nitrogen _____________, bacteria: Use nitrogen gas (N2) to form ammonia (NH3) With _______________, bacteria: Convert ammonium (NH4+) to nitrates (NO3-) With ________________, bacteria: Convert nitrates or nitrites (NO2-) to nitrogen gas

How Does Nitrogen Move Through Ecosystems? (cont’d.) Steps in the nitrogen cycle Nitrogen-fixing __________________ in soil, water, or lichens break bonds in N2 and form ammonia, which is ______________ in water as ammonium (NH4+) and taken up by plants Another group of nitrogen-fixing bacteria forms nodules on roots of peas and other legumes

How Does Nitrogen Move Through Ecosystems? (cont’d.) ____________ get nitrogen by eating plants or one another; bacterial and fungal decomposers ___________________ wastes and remains and return ammonium to the soil Nitrification converts ammonium to nitrates: _____________________ bacteria and ______________ convert ammonium to nitrite (NO2–) _____________ convert nitrites to nitrates (NO3– )

How Does Nitrogen Move Through Ecosystems? (cont’d.) Nitrates are taken up and used by producers Denitrifying bacteria use nitrate for energy and _____________ nitrogen gas into the atmosphere

ANIMATION: Nitrogen cycle Figure 42.10 {Animated} The nitrogen cycle in a land ecosystem To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

How Does Nitrogen Move Through Ecosystems? (cont’d.) Manufactured ammonia fertilizers increase the concentration of H+ and N Essential nutrients ___________ away in soil water Nitrogen ___________ pollutes aquatic habitats Burning fossil fuels releases nitrous oxide, a greenhouse gas contributing to acid rain Nitrogen in acid rain has the same effects as fertilizers

How Does Nitrogen Move Through Ecosystems? (cont’d.) Figure 42.11 A tractor applying industrially produced, nitrogen-rich fertilizer to a cornfield. nitrogen is the nutrient that most commonly limits corn growth. The inset photo shows corn grown with adequate nitrogen (left) and in nitrogen-deficient soil (right).

42.8 How Does Phosphorus Move Through the System? Age structure diagrams show the ______________ of individuals among age groups The broader the base of an age structure diagram, the _________ proportion of young people, and the __________ expected growth More than 1/3 of the world population is in the broad pre-reproductive base World population growth will not be slowed for many years

How Does Phosphorus Move Through the System? (cont’d.) Most phosphorus is _____________ to oxygen as phosphate (PO43– ) in rocks and sediments – and moves in a sedimentary cycle

How Does Phosphorus Move Through the System? (cont’d.) Steps in phosphorus cycle _______________ and _____________ move phosphates from rocks into soil, lakes, and rivers Leaching and runoff carry ____________ phosphates to the ocean Phosphorus settles as ____________ along continental margins Slow movements of Earth’s crust uplift deposits onto land, where weathering releases phosphates from rocks

How Does Phosphorus Move Through the System? (cont’d.) Land plants ______________ dissolved phosphate from soil water Land animals get phosphates by eating plants or one another; phosphorus returns to soil in wastes and remains In seas, producers take up phosphate dissolved in seawater Wastes and remains ______________ phosphates in seawater

How Does Phosphorus Move Through the System? (cont’d.) Phosphorus is often a _________________ for plant growth Phosphate-rich droppings from seabird or bat colonies are used as fertilizer Phosphate-rich rock is also mined for this purpose Water pollution from high-phosphate fertilizers, detergents, or sewage can cause ______________

ANIMATION: Phosphorus Cycle Figure 42.12 {Animated} The phosphorus cycle To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERE

42.9 Toxic Transfers Bioaccumulation Nutrients are not the only things that move up food chains ____________ enter food chains and pass from one trophic level to the next By the process of bioaccumulation

Toxic Transfers (cont’d.) Figure 42.13 Loon with its fish prey. Along with nutrients, the loon takes in any toxic pollutants that accumulated in the fish’s body.