Copyright © 2009 Pearson Education, Inc. Basic Ecology Populations, Communities and Ecosystems

Copyright © 2009 Pearson Education, Inc A community includes all the organisms inhabiting a particular area  Biological community –All the different species of populations living close enough together for potential interaction  Boundaries of the community vary with research questions –Can be a pond –Can be the intestinal microbes of a pond organism

Copyright © 2009 Pearson Education, Inc Competition may occur when a shared resource is limited  Ecological niche –An organism’s role or job in the community such as the biotic and abiotic resources it consumes and where it fits in on the food web.  Competition lowers the carrying capacity of competing populations

Copyright © 2009 Pearson Education, Inc Trophic structure is a key factor in community dynamics  Trophic structure –A pattern of feeding relationships consisting of several different levels  Food chain –Sequence of food transfer up the trophic levels

Copyright © 2009 Pearson Education, Inc.  Producers –Support all other trophic levels –Autotrophs –Photosynthetic producers –Plants on land –Cyanobacteria in water –Protists such as plankton (aka sponge bob) 37.8 Trophic structure is a key factor in community dynamics

Copyright © 2009 Pearson Education, Inc.  Consumers –Heterotrophs –Primary consumers –Secondary consumers –Tertiary consumers –Quaternary consumers  Detritivores and decomposers –Derive energy from dead matter and wastes 37.8 Trophic structure is a key factor in community dynamics

Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain

Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain Primary consumers Grasshopper Zooplankton

Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain Primary consumers Grasshopper Zooplankton Secondary consumers Mouse Herring

Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain Primary consumers Grasshopper Zooplankton Secondary consumers Mouse Herring Snake Tuna Tertiary consumers

Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain Primary consumers Grasshopper Zooplankton Secondary consumers Mouse Herring Snake Tuna Tertiary consumers Hawk Killer whale Quaternary consumers Trophic level

Copyright © 2009 Pearson Education, Inc Food chains interconnect, forming food webs  Food web –A network of interconnecting food chains

Producers (plants) Primary consumers Secondary and primary consumers Tertiary and secondary consumers Quaternary, tertiary, and secondary consumers

Copyright © 2009 Pearson Education, Inc. ECOSYSTEM STRUCTURE AND DYNAMICS

Copyright © 2009 Pearson Education, Inc Ecosystem ecology emphasizes energy flow and chemical cycling  Ecosystem –All the organisms in a community as well as the abiotic environment  Components of ecosystems –Energy flow –Passage of energy through the ecosystem –Chemical cycling –Transfer of materials within the ecosystem

Copyright © 2009 Pearson Education, Inc Primary production sets the energy budget for ecosystems  Primary production –The amount of solar energy converted to chemical energy –Carried out by producers –Produces biomass –Amount of living organic material in an ecosystem

Open ocean Estuary Algal beds and coral reefs Desert and semidesert scrub Tundra Temperate grassland Cultivated land Boreal forest (taiga) Savanna Temperate deciduous forest Tropical rain forest Average net primary productivity (g/m 2 /yr) 1,000 1,500 2,5002,000

Copyright © 2009 Pearson Education, Inc Energy supply limits the length of food chains  A pyramid of production –Illustrates the cumulative loss of energy transfer in a food chain

1,000,000 kcal of sunlight 10 kcal 100 kcal 1,000 kcal 10,000 kcal Producers Primary consumers Secondary consumers Tertiary consumers

Copyright © 2009 Pearson Education, Inc CONNECTION: A production pyramid explains why meat is a luxury for humans  The dynamics of energy flow apply to the human population

Producers Primary consumers Secondary consumers Human meat-eaters Cattle Corn Human vegetarians Trophic level

Copyright © 2009 Pearson Education, Inc The carbon cycle depends on photosynthesis and respiration  Carbon is the major ingredient of all organic molecules  The return of CO 2 to the atmosphere by respiration closely balances its removal by photosynthesis  The carbon cycle is affected by burning wood and fossil fuels

Photosynthesis Decomposers (soil microbes) Cellular respiration Detritus Plants, algae, cyanobacteria Primary consumers Higher-level consumers Burning CO 2 in atmosphere Plant litter; death Wastes; death Decomposition Wood and fossil fuels

Copyright © 2009 Pearson Education, Inc The nitrogen cycle depends on bacteria  Nitrogen is an essential component of proteins and nucleic acids  Nitrogen has two abiotic reservoirs –Air –Soil  Nitrogen fixation converts N 2 to nitrogen used by plants –Carried out by some bacteria and cyanobacteria

Nitrogen (N 2 ) in atmosphere 8 Plant Animal Assimilation by plants Organic compounds Organic compounds Death; wastes Denitrifiers Nitrates in soil (NO 3 – ) Detritus Decomposers Decomposition Nitrifying bacteria Ammonium (NH 4 + ) in soil Nitrogen fixation Nitrogen fixation Nitrogen-fixing bacteria in root nodules Free-living nitrogen-fixing bacteria and cyanobacteria

Decomposers Producer Energy flow Chemical cycling Herbivore (primary consumer) Carnivore (secondary consumer)

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-3b Percentage of maximum life span Percentage of survivors (log scale) III II I

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-4a Time (months) Population size (N)

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-4b Year Breeding male fur seals (thousands)

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig Lynx Snowshoe hare Lynx population size (thousands) Hare population size (thousands) Year

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-9a 1500 Year Population increase Total population size Total population (in billions) Annual increase (in millions)

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-9b Year Birth rate Death rate Rate of increase (r) Birth or death rate per 1,000 population

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-UN3 Time Birth or death rate IIIIVI II

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-9c 1980 Age Male Female Population in millions Total population size = 68,347,479 Population in millions Total population size = 106,202,903 FemaleMale Female Male Population in millions Total population size = 135,172,

Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-UN2 G = rN (K  N)(K  N) K