Visualizing Environmental Science How Ecosystems Work Chapter 5

Transcription

1 Visualizing Environmental Science How Ecosystems Work Chapter 5 Chapter Chapter 77 [chapter [chapter opener opener image] image] Copyright

2 The study of the interactions among organisms and between organisms and their abiotic environment Biotic and abiotic What is Ecology?

3 What is Ecology? Levels of organization Population: a group of organisms of the same species that live in the same place at the same time Communities: all the populations of different species that live and interact together within an area at the same time; note the tidal pool community Ecosystem: community and physical environment

4 A landscape is a region that includes several interacting ecosystems Biosphere layer of Earth that contains all living organisms Compare atmosphere, lithosphere, hydrosphere What is Ecology?

5 The Flow of Energy Through Ecosystems Energy the ability to do work Potential energy stored energy Kinetic energy energy of motion Thermodynamics the study of energy and its transformations First and second law of thermodynamics

6 The First Law of Thermodynamics Energy cannot be created or destroyed Total energy content always the same Energy can change from one form to another Photosynthesis solar energy converted to chemical energy

7 The Second Law of Thermodynamics The amount of usable energy in the universe decreases over time as some is lost as heat Heat less usable and disorganized form of energy Entropy a measure of this disorder

8 The Flow of Energy Through Ecosystems Producers manufacture large organic molecules from simple inorganic molecules Producers are potential food for other organisms This moose is an herbivore or a primary consumer, feeding on the chemical energy stored in grasses

9 The Flow of Energy Through Ecosystems Consumers are animals that consume other organisms Detritivores consumers such as this crab eat organic matter called detritus Decomposers bacteria and fungi that break down dead and decaying organisms

10 The Flow of Energy Through Ecosystems Energy flow the passage of energy in a one-way direction through an ecosystem, occurs in food chains Trophic level each level in a food chain Energy is lost as heat along the way, thus the number of steps in a food chain is limited and less energy is available for organisms at the higher trophic levels

11 The Flow of Energy Through Ecosystems Ecological pyramids graphically represent the relative energy values of each trophic level Pyramids of energy illustrate how energy dissipates into the environment as it moves from one trophic level to the next

12 Ecosystem Productivity Gross primary productivity (GPP) is the rate at which energy is captured during photosynthesis Net primary productivity (NPP) is the amount of biomass found in excess of that broken down by a plant during cellular respiration NPP is expressed in grams of dry matter per square meter per year for the selected ecosystems

13 The Cycling of Matter in Ecosystems Biogeochemical cycles Matter the material of which organisms are composed Humans have GREAT influence on them

14 The Cycling of Matter in Ecosystems The carbon cycle The global movement of carbon between the abiotic environment (atmosphere, ocean) and organisms Atmosphere/ocean photosynthesis cellular respiration/combustion/decomposition atmosphere/ocean Carbon is an essential component of organisms molecules Also essential component of abiotic environment

15 Carbon Cycle 0.04% of the atmosphere Needed to make proteins and carbohydrates Present in several forms such as CO 2, HCO 3-, and CaCO 3 Fossil fuels, coal, oil and natural gas are deposits of carbon compounds Photosynthesis fixes carbon from CO 2 into carbohydrates

16 The Hydrologic Cycle Water circulates among the ocean, land, and atmosphere Creates a renewable supply of water for terrestrial organisms Runoff is water from land to rivers and lakes Watersheds are areas of land where runoff drains

17 The Nitrogen Cycle Nitrogen is an essential component of proteins and nucleic acids Atmosphere is 78% nitrogen gas Five steps in which nitrogen cycles between the abiotic environment and organisms Nitrogen fixation Nitrification Assimilation Ammonification Denitrification

18 The Cycling of Matter in Ecosystems Nitrogen-fixing bacteria carry out nitrogen fixation in soil and aquatic environments This bacteria is fixing nitrogen in the nodules of a pea plant s root Photochemical smog and acid deposition are nitrogenbased air pollutants

19 Most sulfur is underground in sedimentary rocks and minerals Animals get sulfur from plant protein Sulfur gas is a minor part of the atmosphere, but movement of sulfur is substantial Bacteria-driven cycle Burning coal releases sulfur, which causes acid deposition The Sulfur Cycle

20 The Phosphorous Cycle No atmospheric component Cycles between land and organisms Phosphorous in soil is absorbed by plant roots Necessary to make nucleic acids and ATP Phosphorus in fertilizers can cause eutrophication, as in Lake Washington (chapter opener) Anthropogenic loss of terrestrial phosphorus

21 Niche Ecological Niches The totality of an organism s adaptations, its use of resources, and the lifestyle to which it is fitted Habitat Describes the place and function of an organism within the ecosystem The way of life of an organism Part of an organism s niche, the place where the organism lives

22 Fundamental niche the potential, idealized niche Realized niche the actual niche an organism occupies While the fundamental niches of these two lizards initially overlap, the brown anole outcompeted the green anole, restricting is realized niche Generalists vs. specialists Ecological Niches

23 Resource Partitioning One way species avoid or reduce niche overlap Serves to reduce competition for resources Resource partitioning of five warbler species Each species spends most of their time feeding in different portions of the tree

24 Interactions Among Organisms Symbiosis two species living in close association Symbiosis is the result of coevolution, as seen in this honeycreeper s curved bill perfectly suited to sip nectar from the tubular flowers

25 Interactions Among Organisms There are three main types of symbiosis Mutualism, where both organisms benefit The ant obtains food and shelter from the plant and in turn, protects the plant from predators Commensalism, where one benefits but the other is unaffected neither harmed nor helped Parasitism, one benefits at the expense of the other

26 EnviroDiscovery Bee Colonies Under Threat Since 2006, major losses to bee colonies, referred to as colony collapse disorder (CCD) CCD is the result of pesticides, pathogens, parasites, and viruses such as Israeli acute-paralysis virus Bees are important pollinators and many crops are threatened by bee declines Pear trees in China being hand pollinated

27 Interactions Among Organisms Predation the consumption of one species (prey) by another species (predator) Coevolutionary arms race as predators evolve to better catch prey and prey evolve to better escape predator The cheetah sprints at high speeds to catch prey The goldenrod spider uses camouflage to ambush prey

28 Avoiding Predation Social behavior can decrease predation such as adult meerkats standing guard at their burrow, ready to alert the group of danger Chemical defense in prey such as poison glands and bright warning colors Camouflage to hide from predators such as this Indian leaf butterfly

29 Competition The interaction among organisms that vie for the same resources in an ecosystem, such as food or living space Intraspecific competition Interspecific competition

30 Competition Keystone species, such as the gray wolf, is crucial to the maintenance of the ecosystem Not the most abundant, but have influence on entire ecosystem Note the reintroduction of the wolf in 1995 affected the elk population

31 Another keystone species, the sea otter exerts their influence by changing competitive relationships. Keystone Species They help maintain balance in an ecosystem. 3-31

32 Monterey Bay, California

33 Keystone Species