Campbell Biology, 10th Edition, Ecology PDF

CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Min...

CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Minorsky Jackson 52 Ecology Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick © 2014 Pearson Education, Inc.  OUTLINE: Ecology – interactions between organisms and the environment (Ch 52) Earth’s climate and biomes Distribution of Species: biotic and abiotic factors Bio-61 Dr. Joanna  Discovering Ecology Ecology is the scientific study of the interactions between organisms and the environment These interactions determine the distribution of organisms and their abundance Modern ecology includes observation and experimentation Bio-61 HOME Dr. Joanna  The discovery of two new frog species in Papua New Guinea raises many ecological questions – What environmental factors limit their geographic distribution? – What factors (food, pathogens) affect population size? Bio-61 Dr. Joanna  Organismal ecology Population ecology Community ecology Ecosystem ecology Landscape ecology Global ecology Bio-61 Dr. Joanna  Global ecology Landscape ecology The Scope of Ecological Ecosystem ecology Research Ecologists work Community ecology at levels ranging from individual Population ecology organisms to the planet Organismal ecology Bio-61 Dr. Joanna Global Ecology The biosphere is the global ecosystem, the sum of all the planet’s ecosystems Global ecology examines the influence of energy and materials on organisms across the biosphere Landscape Ecology A landscape (or seascape) is a mosaic of connected ecosystems Landscape ecology focuses on the exchanges of energy, materials, and organisms across multiple ecosystems Bio-61 Dr. Joanna Ecosystem Ecology An ecosystem is the community of organisms in an area and the physical factors with which they interact Ecosystem ecology emphasizes energy flow and chemical cycling among the various biotic and abiotic components Community Ecology A community is a group of populations of different species in an area Community ecology examines the effect of interspecific interactions on community structure and organization Bio-61 Dr. Joanna Population Ecology A population is a group of individuals of the same species living in an area Population ecology focuses on factors affecting population size over time Organismal Ecology Organismal ecology studies how an organism’s structure, physiology, and (for animals) behavior meet environmental challenges Organismal ecology includes physiological, evolutionary, and behavioral ecology Bio-61 Dr. Joanna Concept 1: Earth’s climate varies by latitude and season and is changing rapidly The long-term prevailing weather conditions in an area constitute its climate Four major abiotic components of climate are temperature, precipitation, sunlight, and wind Macroclimate consists of patterns on the global, regional, and landscape level Microclimate consists of very fine patterns, such as those encountered by the community of organisms underneath a fallen log Bio-61 Dr. Joanna Latitudinal Variation in Sunlight Intensity The angle at which sunlight hits Earth affects its intensity, the amount of heat and light per unit of surface area The intensity of sunlight is strongest in the tropics (between 23.5° north latitude and 23.5° south latitude) where sunlight strikes Earth most directly Atmosphere 90°N (North Pole) Low angle of incoming sunlight 23.5°N (Tropic of Cancer) Sun overhead at equinoxes 0° (Equator) 23.5°S (Tropic of Capricorn) Low angle of incoming sunlight 90°S (South Pole) Bio-61 Latitudinal variation in sunlight intensity Dr. Joanna  Global air circulation and precipitation patterns play major roles in determining climate patterns Water evaporates in the tropics, and warm, wet air masses flow from the tropics toward the poles 66.5N (Arctic Circle) 60 N Descending Westerlies dry air 30N 30N absorbs moisture. Northeast trades Ascending moist air 0 releases moisture. Southeast trades 30S Westerlies 0 60S 66.5S (Antarctic Circle) Global air circulation and precipitation patterns Bio-61 Dr. Joanna  Global Climate Patterns Global climate patterns are determined largely by solar energy and Earth’s movement in space The warming effect of the sun causes temperature variations, which drive evaporation and the circulation of air and water This causes latitudinal variations in climate Bio-61 Dr. Joanna  Rising air masses release water and cause high precipitation, especially in the tropics Dry, descending air masses create arid climates, especially near 30° north and south Air flowing close to Earth’s surface creates predictable global wind patterns Cooling trade winds blow from east to west in the tropics; prevailing westerlies blow from west to east in the temperate zones Bio-61 Dr. Joanna  Regional and Local Effects on Climate Climate is affected by seasonality, large bodies of water, and mountains Bio-61 Dr. Joanna  Seasonal variation in sunlight intensity March equinox December June solstice solstice Constant tilt of 23.5 60N 30N 0 (equator) 30S September equinox Bio-61 Dr. Joanna  Seasonality Seasonal variations of light and temperature increase steadily toward the poles Seasonality at high latitudes is caused by the tilt of Earth’s axis of rotation and its annual passage around the sun Belts of wet and dry air straddling the equator shift throughout the year with the changing angle of the sun Changing wind patterns affect ocean currents Bio-61 Dr. Joanna Global circulation of surface water in the oceans Labrador Current Gulf California Current Stream North Atlantic 30N North Pacific Subtropical Subtropical Gyre Gyre Equator Indian South Ocean Atlantic Subtropical South Pacific Subtropical Gyre 30S Subtropical Gyre Gyre Antarctic Circumpolar Current Bio-61 Dr. Joanna  Bodies of Water Oceans, their currents, and large lakes moderate the climate of nearby terrestrial environments Currents flowing toward the equator carry cold water from the poles; currents flowing away from the equator carry warm water toward the poles Bio-61 Dr. Joanna  During the day, air rises over warm land and draws a cool breeze from the water across the land As the land cools at night, air rises over the warmer water and draws cooler air from land back over the water, which is replaced by warm air from offshore Bio-61 Dr. Joanna  How large bodies of water and mountains affect climate 2 Precipitation 3 Rain shadow 1 Cool air flow Leeward side of mountains Mountain range Ocean Bio-61 Dr. Joanna  Mountains Rising air releases moisture on the windward side of a peak and creates a “rain shadow” as it absorbs moisture on the leeward side Mountains affect the amount of sunlight reaching an area In the Northern Hemisphere, south-facing slopes receive more sunlight than north-facing slopes Every 1,000 m increase in elevation produces a temperature drop of approximately 6C Bio-61 Dr. Joanna Glacial animation Global Climate Change Changes in Earth’s climate can profoundly affect the biosphere One way to predict the effects of future global climate change is to study previous changes As glaciers retreated 16,000 years ago, tree distribution patterns changed As climate changes, species that have difficulty dispersing may have smaller ranges or could become extinct https://www.youtube.com/watch?v=oA1sphuyazY – 25min Fate of Antarctica Bio-61 melting @ 11min Dr. Joanna © 2 0 1 Global Climate Change 7 P e a Climate change is a directional change to r s the global climate lasting three decades or o more n E d Burning of fossil fuels and deforestation u have increased the concentration of c a greenhouse gases in the atmosphere t i As a result, wind and precipitation patterns o n are shifting, and global temperature and , I the frequency of extreme weather events n cBio-61 have increased Dr. Joanna  One way to predict the effects of future global climate change is to study American beech how species (Fagus grandifolia) responded to changes in the past The geographic ranges of many species have shifted in response to climate change Determining the location of suitable habitat under different climate (a) Current range (b) 4.5ºC warming (c) 6.5ºC warming scenarios can help over next century over next century predict future range Bio-61 shifts Dr. Joanna  Species that have difficulty dispersing or face a shortage of suitable habitat may have smaller ranges or could become extinct For example, the geographic ranges of 67 bumblebee species in the Northern Hemisphere have decreased Bio-61 Dr. Joanna Concept 2: The structure and distribution of terrestrial biomes are controlled by climate and disturbance Biomes are major life zones characterized by vegetation type (terrestrial biomes) or physical environment (aquatic biomes) Climate is very important in determining why terrestrial biomes are found in certain areas Bio-61 Dr. Joanna  Climate and Terrestrial Biomes 30N Tropic of Cancer Equator Tropic of Capricorn 30S Tropical forest Temperate broadleaf forest Savanna Northern coniferous forest Desert Tundra Chaparral High mountains Bio-61 Temperate grassland Polar ice Dr. Joanna A Desert climograph Temperate grassland plots the Temperate broadleaf annual mean forest Tropical forest temperature 30 and temperature (C) Northern Annual mean precipitation 15 coniferous forest in a region 0 Arctic and alpine tundra −15 0 100 200 300 400 Bio-61 Annual mean precipitation (cm) Dr. Joanna  General Features of Terrestrial Biomes Terrestrial biomes are often named for major physical or climatic factors and for vegetation Terrestrial biomes usually grade into each other, without sharp boundaries The area of intergradation, called an ecotone, may be wide or narrow Bio-61 Dr. Joanna  Vertical layering is an important feature of terrestrial biomes, and in a forest it might consist of an upper canopy, low-tree layer, shrub understory, ground layer of herbaceous plants, forest floor, and root layer Layering of vegetation in all biomes provides diverse habitats for animals The species composition of each kind of biome varies from one location to another Bio-61 Dr. Joanna  Similar characteristics can arise in distant biomes through convergent evolution – For example, cacti in North America and euphorbs in African deserts appear similar but are from different evolutionary lineages Euphorbia Cereus sp. canariensis Bio-61 Dr. Joanna Disturbance and Terrestrial Biomes Disturbance is an event such as a storm, fire, or human activity that changes a community – For example, frequent fires can kill woody plants and maintain the characteristic vegetation of a savanna – For example, hurricanes create openings in forests that allow different species to grow In many biomes, even dominant plants depend on periodic disturbance Bio-61 Dr. Joanna Tropical Forest Distribution is in equatorial and subequatorial regions In tropical rain forests, rainfall is relatively constant, while in tropical dry forests precipitation is highly seasonal Temperature is high year-round (25–29C) with little seasonal variation Bio-61 A tropical rain forest in Costa Rica Dr. Joanna  Tropical forests are vertically layered, and competition for light is intense Tropical forests are home to millions of animal species, including an estimated 5– 30 million still undescribed species of insects, spiders, and other arthropods Rapid human population growth is now destroying many tropical forests Bio-61 Dr. Joanna Desert plants are adapted for heat and desiccation tolerance, water storage, and reduced leaf surface area Common desert animals include many kinds of snakes and lizards, scorpions, ants, beetles, migratory and resident birds, and seed-eating rodents; many are nocturnal Urbanization and conversion to irrigated agriculture have reduced the natural biodiversity of some deserts Organ Pipe Cactus National Monument, Arizona Bio-61 Dr. Joanna Distribution includes equatorial and subequatorial regions Precipitation is seasonal with dry seasons lasting 8–9 months Savanna temperature averages (24–29C) but is more seasonally variable than in the tropics Bio-61 A savanna in Kenya Dr. Joanna  Grasses and forbs make up most of the ground cover The dominant plant species are fire- adapted and tolerant of seasonal drought Common inhabitants include insects and mammals such as wildebeests, zebras, lions, and hyenas Fires set by humans may help maintain this biome Bio-61 Dr. Joanna  Chaparral Chaparral occurs in midlatitude coastal regions on several continents Precipitation is highly seasonal with rainy winters and dry summers Summer is hot (30C+); fall, winter, and spring are cool (10–12C) Bio-61 Dr. Joanna Chaparral occurs in midlatitude coastal regions on several continents Precipitation is highly seasonal with rainy winters and dry summers Summer is hot (30C+); fall, winter, and spring are cool (10–12C) Bio-61 An area of chaparral in California Dr. Joanna  The chaparral is dominated by shrubs, small trees, grasses, and herbs; many plants are adapted to fire and drought Animals include amphibians, birds and other reptiles, insects, small mammals, and browsing mammals Humans have reduced chaparral areas through agriculture and urbanization Bio-61 Dr. Joanna Temperate grasslands are found on many continents Precipitation is highly seasonal Winters are cold (often below −10C) and dry; summers are hot (often near 30C) and wet Bio-61 A grassland in Mongolia Dr. Joanna  The dominant plants, grasses and forbs, are adapted to droughts and fire Native mammals include large grazers such as bison and wild horses and small burrowers such as prairie dogs Most grasslands have been converted to farmland Bio-61 Dr. Joanna  Northern Coniferous Forest The northern coniferous forest, or taiga, spans northern North America and Eurasia and is the largest terrestrial biome on Earth Precipitation varies; some have periodic droughts and others, especially near coasts, are wet Winters are cold; summers may be hot (e.g., Siberia ranges from −50C to 20C) Bio-61 Dr. Joanna The northern coniferous forest, or taiga, spans northern North America and Eurasia and is the largest terrestrial biome on Earth Precipitation varies; some have periodic droughts and others, especially near coasts, are wet Winters are cold; summers may be hot (e.g., Siberia ranges from −50C to 20C) Bio-61 A coniferous forest in Norway Dr. Joanna  Conifers such as pine, spruce, fir, and hemlock dominate The conical shape of conifers prevents too much snow from accumulating and breaking their branches Animals include migratory and resident birds and large mammals such as moose, brown bears, and Siberian tigers Some forests are being logged at an alarming rate Bio-61 Dr. Joanna Distribution is primarily at midlatitudes in the Northern Hemisphere, with smaller areas in Chile, South Africa, Australia, and New Zealand Significant amounts of precipitation fall during all seasons as rain or snow Winters average 0C; summers are hot and humid (near 35C) Bio-61 A temperate broadleaf forest in New Jersey Dr. Joanna  A mature temperate broadleaf forest has vertical layers, including a closed canopy, understory trees, a shrub layer, and an herb layer The dominant plants are deciduous trees in the Northern Hemisphere and evergreen eucalyptus in Australia Mammals, birds, and insects make use of all vertical layers in the forest In the Northern Hemisphere, many mammals hibernate in the winter These forests have been heavily settled on all continents but are recovering in places Bio-61 Dr. Joanna Tundra covers expansive areas of the Arctic; alpine tundra exists on high mountaintops at all latitudes Precipitation is low in arctic tundra and higher in alpine tundra Winters are cold (below −30C); summers are relatively cool (less than 10C) Bio-61 Dovrefjell National Park, Norway, in autumn Dr. Joanna  Vegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen) Permafrost, a permanently frozen layer of soil, restricts the growth of plant roots Mammals include musk oxen, caribou, reindeer, bears, wolves, and foxes; many migratory bird species nest in the summer Settlement is sparse, but tundra has become the focus of oil and mineral extraction Bio-61 Dr. Joanna Concept 3: Aquatic biomes are diverse and dynamic systems that cover most of Earth Aquatic biomes are characterized by their physical environment They show less latitudinal variation than terrestrial biomes Marine biomes have salt concentrations of about 3% The largest marine biome is made up of oceans, which cover about 75% of Earth’s surface and have an enormous impact on the biosphere Bio-61 Dr. Joanna  Freshwater biomes have salt concentrations of less than 0.1% Freshwater biomes are closely linked to soils and the biotic components of the surrounding terrestrial biome Bio-61 Dr. Joanna Zonation in aquatic environments (b) Marine zonation Intertidal zone Neritic zone Oceanic zone 0 (a) Zonation in a lake 200 m Photic Littoral zone Limnetic Continental zone zone shelf Pelagic zone Photic Benthic Pelagic zone Aphotic zone zone zone Benthic zone Aphotic 2,000– zone 6,000 m Abyssal zone Bio-61 Dr. Joanna  Zonation in Aquatic Biomes Many aquatic biomes are stratified into zones or layers defined by light penetration, temperature, and depth The upper photic zone has sufficient light for photosynthesis, while the lower aphotic zone receives little light The photic and aphotic zones make up the pelagic zone Deep in the aphotic zone lies the abyssal zone with a depth of 2,000 to 6,000 m Bio-61 Dr. Joanna  The organic and inorganic sediment at the bottom of all aquatic zones is called the benthic zone The communities of organisms in the benthic zone are collectively called the benthos Detritus, dead organic matter, falls from the productive surface water and is an important source of food Bio-61 Dr. Joanna Seasonal Winter Spring turnover in lakes with winter ice 2 0 4 cover 4C 4C Summer Autumn 22 4 18 8 4C 4C Thermocline Bio-61 Dr. Joanna  In oceans and most lakes, a temperature boundary called the thermocline separates the warm upper layer from the cold deeper water Many lakes undergo a semiannual mixing of their waters called turnover Turnover mixes oxygenated water from the surface with nutrient-rich water from the bottom Bio-61 Dr. Joanna  Communities in aquatic biomes vary with depth, light penetration, distance from shore, and position in the pelagic or benthic zone Most organisms occur in the relatively shallow photic zone The aphotic zone in oceans is extensive but harbors little life Bio-61 Dr. Joanna  Aquatic Biomes Major aquatic biomes can be characterized by their physical environment, chemical environment, geological features, photosynthetic organisms, and heterotrophs Bio-61 Dr. Joanna  An oligotrophic lake in Jasper National Park, Alberta A eutrophic lake in the Okavango Delta, Botswana Bio-61 Dr. Joanna  Lakes Size varies from small ponds to very large lakes Temperate lakes may have a seasonal thermocline; tropical lowland lakes have a year-round thermocline Oligotrophic lakes are nutrient-poor and generally oxygen-rich Eutrophic lakes are nutrient-rich and often depleted of oxygen in deep zones or throughout if ice covered in winter Bio-61 Dr. Joanna  Oligotrophic lakes have less surface area relative to depth than eutrophic lakes Rooted and floating aquatic plants live in the shallow and well-lighted littoral zone close to shore Water is too deep in the limnetic zone to support rooted aquatic plants; small drifting animals called zooplankton graze on the phytoplankton Bio-61 Dr. Joanna  Zooplankton are drifting heterotrophs that graze on the phytoplankton Invertebrates live in the benthic zone Fishes live in all zones with sufficient oxygen Human-induced nutrient enrichment can lead to algal blooms, oxygen depletion, and fish kills Bio-61 Dr. Joanna  A basin wetland in the United Kingdom Bio-61 Dr. Joanna  Wetlands A wetland is a habitat that is inundated by water at least some of the time and that supports plants adapted to water- saturated soil Wetlands have high organic production and decomposition and have low dissolved oxygen Wetlands can develop in shallow basins, along flooded river banks, or on the coasts of large lakes and seas Bio-61 Dr. Joanna  Wetlands are among the most productive biomes on Earth Plants include lilies, cattails, sedges, tamarack, and black spruce Wetlands are home to diverse invertebrates and birds, as well as otters, frogs, and alligators Humans have destroyed up to 90% of wetlands; wetlands purify water and reduce flooding Bio-61 Dr. Joanna  A headwater stream in Washington The Loire river in France, far from its headwaters Bio-61 Dr. Joanna  Streams and Rivers The most prominent physical characteristic of streams and rivers is current Headwaters are generally cold, clear, turbulent, swift, and oxygen-rich; they are often narrow and rocky Downstream waters form rivers and are generally warmer, more turbid, and well oxygenated; they are often wide and meandering and have silty bottoms Bio-61 Dr. Joanna  Headwater streams may be rich in phytoplankton or rooted aquatic plants A diversity of fishes and invertebrates inhabit unpolluted rivers and streams Pollution degrades water quality and kills aquatic organisms Damming and flood control impair natural functioning of stream and river ecosystems Bio-61 Dr. Joanna  An estuary in southern Spain Bio-61 Dr. Joanna  Estuaries An estuary is a transition area between river and sea Salinity varies with the rise and fall of the tides Estuaries are nutrient-rich and highly productive Estuaries include a complex network of tidal channels, islands, natural levees, and mudflats Bio-61 Dr. Joanna  Saltmarsh grasses and algae are the major producers An abundant supply of food attracts marine invertebrates, fish, waterfowl, and marine mammals Humans consume oysters, crabs, and fish Human interference upstream has disrupted estuaries worldwide Bio-61 Dr. Joanna  A rocky intertidal zone on the Oregon coast Bio-61 Dr. Joanna  Intertidal Zones An intertidal zone is periodically submerged and exposed by the tides Intertidal organisms are challenged by variations in temperature and salinity and by the mechanical forces of wave action Oxygen and nutrient levels are high Substrate varies from rocky to sandy Bio-61 Dr. Joanna  Sandy zones protected from vigorous waves support sea grass and algae; rocky zones support attached marine algae In rocky zones, many animals have structural adaptations for attaching to the hard substrate In sandy zones, worms, clams, and crustaceans bury themselves in sand Other animals include sponges, sea anemones, echinoderms, and small fishes Oil pollution has disrupted many intertidal areas Bio-61 Dr. Joanna  Open ocean near Iceland Bio-61 Dr. Joanna  Oceanic Pelagic Zone The oceanic pelagic zone is constantly mixed by wind-driven oceanic currents Oxygen levels are high Turnover in temperate oceans renews nutrients in the photic zones; year-round stratification in tropical oceans leads to lower nutrient concentrations This biome covers approximately 70% of Earth’s surface Bio-61 Dr. Joanna  Phytoplankton and zooplankton are the dominant organisms in this biome; also found are free-swimming animals Zooplankton includes protists, worms, copepods, krill, jellies, and invertebrate larvae Other animals include squids, fishes, sea turtles, and marine mammals Overfishing has depleted fish stocks Humans have polluted oceans with dumping of waste Bio-61 Dr. Joanna  A coral reef in the Red Sea Bio-61 Dr. Joanna  Coral Reefs Coral reefs are formed from the calcium carbonate skeletons of corals (cnidarians) Shallow reef-building corals live in the photic zone in warm (about 20–30C), clear water; deep−sea corals live at depths of 200–1,500 m Corals require high oxygen concentrations and a solid substrate for attachment A coral reef progresses from a fringing reef to a barrier reef to a coral atoll Bio-61 Dr. Joanna  Corals form a mutualistic relationship with unicellular algae, which provide them with organic molecules In addition to corals, other invertebrates and fish are also exceptionally diverse Collection of coral skeletons, overfishing, global warming, pollution, and aquaculture are threats to coral reef ecosystems Bio-61 Dr. Joanna  Marine Benthic Zone A deep-sea hydrothermal vent community Bio-61 Dr. Joanna  Marine Benthic Zone The marine benthic zone consists of the seafloor below the surface waters of the coastal, or neritic, zone and the offshore pelagic zone Organisms in the very deep benthic (abyssal) zone are adapted to continuous cold and extremely high water pressure Substrate is mainly soft sediments; some areas are rocky Bio-61 Dr. Joanna  Shallow areas contain seaweeds and filamentous algae Deep-sea hydrothermal vents of volcanic origin on mid-oceanic ridges are surrounded by unique chemoautotrophic prokaryotes, as well as echinoderms and arthropods Neritic benthic communities include invertebrates and fishes Overfishing and dumping of waste have depleted fish populations Bio-61 Dr. Joanna Concept 4: Interactions between organisms and the environment limit the distribution of species Species distributions are the result of ecological and evolutionary interactions through time Ecological time is the minute-to-minute time frame of interactions between organisms and the environment Evolutionary time spans many generations and captures adaptation through natural Bio-61 selection Dr. Joanna  Flowchart of Factors limiting geographic distribution Yes Area inaccessible or insufficient time Why is species Does dispersal X absent from limit its Do biotic factors an area? distribution? (other species) No limit its distribution? Yes Predation, parasitism, Chemical competition, disease factors Water, oxygen, salinity, pH, soil nutrients, etc. Do abiotic factors No limit its Temperature, light, soil distribution? Physical structure, fire, moisture, etc. factors Bio-61 Dr. Joanna  ARIZONA CALIFORNIA Both biotic and abiotic factors BAJA CALIFORNIA influence BAJA species CALIFORNIA SONORA SUR distribution For example, temperature, GULF water availability, OF and interspecific CALIFORNIA N interactions, affect the distribution of 100 km the saguaro cacti Sonoran desert; Saguaro cacti observed Bio-61 Dr. Joanna  Every environment is characterized by differences in – Abiotic factors, including nonliving attributes such as temperature, light, water, and nutrients – Biotic factors, including other organisms that are part of an individual’s environment Bio-61 Dr. Joanna  Biotic Factors Biotic factors that affect the distribution of organisms may include – Predation – Herbivory For example, sea urchins can limit the distribution of seaweeds – Competition – Mutualism – Parasitism Bio-61 Dr. Joanna  Does feeding by sea urchins limit seaweed distribution? Sea urchin Limpet 100 Both limpets 80 and urchins Seaweed cover (%) removed 60 Only urchins removed 40 Only limpets removed 20 Control (both urchins and limpets present) 0 August February August February 1982 1983 1983 1984 Bio-61 Dr. Joanna  Abiotic Factors Abiotic factors affecting the distribution of organisms include – Temperature – Water – Oxygen – Salinity – Sunlight – Soil Most abiotic factors vary in space and time Bio-61 Dr. Joanna  Temperature Environmental temperature is an important factor in the distribution of organisms because of its effects on biological processes Cells may freeze and rupture below 0°C, while most proteins denature above 45°C Mammals and birds expend energy to regulate their internal temperature Bio-61 Dr. Joanna  A sea urchin’s expanding range AUSTRALIA 1 Southern TASMANIA portion of C. rodgersii native range AUSTRALIA East Australian Current 1960s 2 Expanded range 1978 of C. rodgersii; kelp communities TASMANIA decimated 1980s 1980s 1980s 2005 3 Continuation of expanded range; kelp communities 100 km threatened Bio-61 Dr. Joanna  Range shifts in response to climate change can dramatically affect the distribution of other species – For example, the long-spined sea urchin (C. rodgersii) expanded its range in response to increasing water temperature – C. rodgersii consumed the seaweed in its new range and destroyed the diverse communities that formerly inhabited the seaweed stands Bio-61 Dr. Joanna  Water and Oxygen Water availability in habitats is another important factor in species distribution Desert organisms exhibit adaptations for water conservation Water affects oxygen availability as oxygen diffuses slowly in water Oxygen concentrations can be low in deep oceans and deep lakes Bio-61 Dr. Joanna  Salinity Salt concentration affects the water balance of organisms through osmosis Most aquatic organisms are restricted to either freshwater or saltwater habitats Few terrestrial organisms are adapted to high- salinity habitats Salmon are able to migrate between freshwater and ocean Bio-61 Dr. Joanna  Sunlight Light intensity and quality (wavelength) affect photosynthesis Shading by leaves makes competition for light intense on the forest floor Water absorbs light; as a result, in aquatic environments most photosynthesis occurs near the surface In deserts, high light levels increase temperature and can stress plants and animals Bio-61 Dr. Joanna  Rocks and Soil Many characteristics of soil limit the distribution of plants and thus the animals that feed on them – Physical structure – pH – Mineral composition Bio-61 Dr. Joanna © 2 0 1 7 Concept 5: Ecological change and P e evolution affect one another over a r long and short periods of time s o n Ecological interactions can cause E d evolutionary change, and vice versa u c – For example, increase in offspring size a evolves rapidly in Trinidadian guppies when t i predators are removed o n – Evolution of larger body sizes affects nutrient , cycling in guppy habitats I n cBio-61 Dr. Joanna  Ecological change Alters outcome Alters selective of ecological pressures in interactions population Evolutionary change Bio-61 Dr. Joanna  CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Minorsky Jackson 53 Population Ecology Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick © 2014 Pearson Education, Inc.  OUTLINE: Factors for describing a population (Ch 53) Models for population growth Human Population Bio-61 Dr. Joanna  Turtle Tracks Population ecology explores how biotic and abiotic factors influence density, distribution, size, and age structure of populations – For example, the number of loggerhead turtle hatchlings that survive their first journey to the ocean is affected by both biotic and abiotic factors Bio-61 Dr. Joanna  Concept 6: Biological processes influence population density, dispersion, and demographics A population is a group of individuals of a single species living in the same general area Populations are described by their boundaries and size Bio-61 Dr. Joanna  Density and Dispersion Density is the number of individuals per unit area or volume Dispersion is the pattern of spacing among individuals within the boundaries of the population Population size can be estimated by either extrapolation from small samples, an index of population size (e.g., number of nests), or the mark-recapture method Bio-61 Dr. Joanna  sn N= x Determining Population Size Using the Mark- recapture method – Scientists capture, tag, and release a random sample of individuals (s) in a population – Marked individuals are given time to mix back into the population – Scientists capture a second sample of individuals (n), and note how many of them are marked (x) – Population size (N) is estimated by Bio-61 Dr. Joanna Density is the result of an interplay between processes that add individuals to a population and those that remove individuals Immigration is the influx of new individuals from other areas Emigration is the movement of individuals out of a population Births Deaths Deaths and emigration Births and immigration remove individuals add individuals to from a population. a population. Immigration Bio-61 Emigration Dr. Joanna  (a) Clumped Patterns of In a clumped dispersion, dispersion individuals aggregate in within a patches population’s geographic range (b) Uniform (c) Random It may be influenced by social The position of each individual is Bio-61 interactions such as territoriality independent of other individuals Dr. Joanna  Demographics Demography is the study of the vital statistics of a population and how they change over time Death rates and birth rates are of particular interest to demographers Bio-61 Dr. Joanna  A life table is an age-specific summary of the survival pattern of a population Bio-61 Dr. Joanna  Survivorship Curves A survivorship curve is a graphic way of representing the data in a life table The survivorship curve for Belding’s ground squirrels shows a relatively constant death rate Bio-61 Dr. Joanna  Idealized survivorship curves: Types I, II, and III 1,000 Number of survivors (log scale) I 100 II 10 III 1 0 50 100 Percentage of maximum life span Bio-61 Dr. Joanna  Survivorship curves can be classified into three general types – Type I: Low death rates during early and middle life and an increase in death rates among older age groups – Type II: A constant death rate over the organism’s life span – Type III: High death rates for the young and a lower death rate for survivors Many species are intermediate to these curves Bio-61 Dr. Joanna  Reproductive Rates For species with sexual reproduction, demographers often concentrate on females in a population Ecologists use many approaches to estimate the number of breeding females – For example, DNA profiling was used to determine the number of female loggerhead turtles laying eggs in a season Bio-61 Dr. Joanna  Part 1: Developing the Database Genetic profiles stored in database Short tandem repeats at 14 loci amplified by PCR Skin samples collected Genetic profiles compared to database Part 2: Comparing Samples to the Database Eggshell sample #74 Short tandem repeats at 14 loci Genetic amplified by PCR profiles determined Eggshell collected from nest Bio-61 Dr. Joanna Concept 7: The exponential model describes population growth in an idealized, unlimited environment It is useful to study population growth in an idealized situation Idealized situations help us understand the capacity of species to increase and the conditions that may facilitate this growth Bio-61 Dr. Joanna  Per Capita Rate of Increase Change in Immigrants Emigrants population = Births + entering – Deaths – leaving size population population If immigration and emigration are ignored, a population’s growth rate (per capita increase) equals birth rate minus death rate Bio-61 Dr. Joanna Population growth predicted by the exponential model 2,000 dN = 1.0N dt Population size (N) 1,500 dN = 0.5N dt 1,000 500 0 0 5 10 15 Number of generations Bio-61 Dr. Joanna  Exponential Growth Exponential population growth is population increase under idealized conditions Under these conditions, the rate of increase is at its maximum, denoted as rmax The equation of exponential population growth is dN = rinstN dt Bio-61 Dr. Joanna  Exponential population growth results in a J-shaped curve The rate of increase is constant, but the population accumulates more new individuals per unit time when it is large than when it is small Bio-61 Dr. Joanna Exponential growth in the African elephant population of Kruger National Part, South Africa 8,000 Elephant population 6,000 4,000 2,000 0 1900 1910 1920 1930 1940 1950 1960 1970 Year Bio-61 after hunting was banned Dr. Joanna Concept 8: The logistic model describes how a population grows more slowly as it nears its carrying capacity Exponential growth cannot be sustained for long in any population A more realistic population model limits growth by incorporating carrying capacity Carrying capacity (K) is the maximum population size the environment can support Carrying capacity varies with the abundance of limiting resources Bio-61 Dr. Joanna Population growth predicted by the logistic model Exponential growth 2,000 dN = 1.0N dt Population size (N) 1,500 K = 1,500 Logistic growth dN 1,500 − N = 1.0N dt 1,500 1,000 500 Population growth begins slowing here. 0 0 5 10 15 Number of generations Bio-61 Dr. Joanna  The Logistic Growth Model In the logistic population growth model, the per capita rate of increase declines as carrying capacity is reached The logistic model of population growth produces a sigmoid (S-shaped) curve New individuals are added to the population most rapidly at intermediate population sizes The population growth rate decreases as N approaches K Bio-61 Dr. Joanna  The logistic model fits few real populations but is useful for estimating possible growth Conservation biologists can use the model to estimate the critical size below which populations may become extinct Bio-61 Dr. Joanna Concept 9: Many factors that regulate population growth are density dependent There are two general questions about regulation of population growth – What environmental factors stop a population from growing indefinitely? – Why do some populations show radical fluctuations in size over time, while others remain stable? Bio-61 Dr. Joanna  Population Change and Population Density In density-independent populations, birth rate and death rate do not change with population density In density-dependent populations, birth rates fall and death rates rise with population density Density-dependent birth and death rates are an example of negative feedback that regulates population growth Bio-61 Dr. Joanna Mechanisms of density- dependent regulation Competition for resources Disease Predation Territoriality Bio-61 Intrinsic factors Toxic wastes 5 Dr. µm Joanna  Population Dynamics The study of population dynamics focuses on the complex interactions Snowshoe hare Number of hares Number of lynx between biotic (thousands) (thousands) and abiotic factors that Lynx cause variation in population size Population cycles in the snowshoe hare and lynx Bio-61 Dr. Joanna Concept 10: The human population is no longer growing exponentially but is still increasing rapidly No population can grow indefinitely, and humans are no exception Bio-61 Dr. Joanna  THE HUMAN POPULATION The human population now stands at over 6.4 6 billion 5 Even with 4 slowing 3 growth, 2 predicted to The Plague reach 7.3 to 8 1 billion by 0 8000 4000 3000 2000 1000 0 1000 2000 2025 B.C. B.C. B.C. B.C. B.C. A.D. A.D. Bio-61 Dr. Joanna  Annual percent increase in the global human 2.2 population (data as of 2014) 2.0 1.8 Annual percent increase 1.6 1.4 1.2 2014 Projected 1.0 data 0.8 0.6 0.4 0.2 0 1950 1975 2000 2025 2050 Bio-61 Year Dr. Joanna World Population Growth Bio-61 Dr. Joanna  Human Population Growth Creeps Back Up New U.N. estimates suggest 9.6 billion people by 2050 By Colin Sullivan and ClimateWire. Scientific American, 06/2013 Bio-61 Dr. Joanna  In this model, as resources are depleted, global food production and industrial output falls, leading to a drop in population after 2030 Bio-61 Dr. Joanna Bio-61 Dr. Joanna Bio-61 Dr. Joanna Annual per capita energy use around the world Energy use (GJ): Bio-61 > 300 150–300 50–150 10–50 < 10 Dr. Joanna  What is Earth's human carrying capacity? Ecological footprint –Amount of land needed to support human demands on Earth's resources –Exceeds ecological capacity in many countries Bio-61 Dr. Joanna  CONNECTION: An ecological footprint is a measure of resource consumption Ecological footprint helps understand resource availability and usage The United States has a – Big ecological footprint Copyright © 2009 Pearson Education, Inc. Bio-61 Dr. Joanna  World map with area corresponding to ecological footprint. North Europe America Asia Africa > 5.4 global ha per person 3.6–5.4 global ha per person 1.8–3.6 global ha per person South 0.9–1.8 global ha per person America < 0.9 global ha per person Australia Insufficient data Bio-61 Dr. Joanna  What is Earth's human carrying capacity? World is already in ecological deficit Problem is not just overpopulation, but Traffic in downtown Cairo, Egypt overconsumption Possible limiting factors: food, Manhattan, space New York City Refugee camp in Zaire Bio-61 Dr. Joanna Recent Factors to increase life span Agricultural Development Animal Domestication Industrial Revolution Vaccines Antibiotics Tool-making, the advent of agriculture, and industrialization each allowed humans to raise their global carrying capacity Bio-61 Dr. Joanna  Population Age Structures Bio-61 Dr. Joanna Population Age Structures Rapid growth Slow growth No growth Afghanistan United States Italy Male Female Age Male Female Age Male Female 85+ 85+ 80–84 80–84 75–79 75–79 70–74 70–74 65–69 65–69 60–64 60–64 55–59 55–59 50–54 50–54 45–49 45–49 40–44 40–44 35–39 35–39 30–34 30–34 25–29 25–29 20–24 20–24 15–19 15–19 10–14 10–14 5–9 5–9 0–4 0–4 10 8 6 4 2 0 2 4 6 8 10 5 4 3 2 1 0 1 2 3 4 5 5 4 3 2 1 0 1 2 3 4 5 Percent of population Percent of population Percent of population My retirement will come from your salary  Bio-61 Dr. Joanna Population momentum in China Bio-61 Dr. Joanna The Sociology, Economics, and Politics of Population Growth Computer models of human population growth – Predict that by about 2050, the human population will peak at about 10.6 billion Technology – Has undoubtedly increased Earth’s carrying capacity, but no population can continue to grow indefinitely Bio-61 Dr. Joanna  Easter Island Bio-61 Dr. Joanna Easter Island story Bio-61 Dr. Joanna Bio-61 Dr. Joanna  Lecture Notes Bio-61 Dr. Joanna  Lecture Notes Bio-61 Dr. Joanna  Lecture Notes Bio-61 Dr. Joanna  Lecture Notes Bio-61 Dr. Joanna  Lecture Notes Bio-61 Dr. Joanna  Lecture Notes Bio-61 Dr. Joanna  Lecture Notes Bio-61 Dr. Joanna  CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Minorsky Jackson 54 Community Ecology Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick © 2014 Pearson Education, Inc.  OUTLINE: Community interactions (Ch 54) Diversity and trophic structure Pathogen effect Bio-12 Dr. Joanna  Communities in Motion A biological community is an assemblage of populations of various species living close enough for potential interaction Which species benefits from this interaction? Bio-12 Dr. Joanna Concept 1: Community interactions are classified by whether they help, harm, or have no effect on the species involved Ecologists call relationships between species in a community interspecific interactions Examples are competition, predation, herbivory, symbiosis (parasitism, mutualism, and commensalism), and facilitation Interspecific interactions can affect the survival and reproduction of each species, and the effects can be summarized as positive (+), negative (−), or no effect (0) Bio-12 Dr. Joanna  Competition Interspecific competition (−/− interaction) occurs when species compete for a resource in short supply Bio-12 Dr. Joanna  Ecological Niches and Natural Selection The sum of a species’ use of biotic and abiotic resources is called the species’ ecological niche Bio-12 Dr. Joanna  Experiment High tide Chthamalus Chthamalus Balanus realized niche A species’ Balanus fundamental niche is realized niche the niche potentially Ocean Low tide occupied by that species A species’ realized Interspecific competition niche is the niche Results High tide actually occupied by that species As a result of competition, a species’ Chthamalus fundamental niche may fundamental niche differ from its realized niche Ocean Low tide Bio-12 Dr. Joanna Resource partitioning among Dominican Republic lizards A. distichus perches A. insolitus usually perches on fence posts and on shady branches. other sunny surfaces. A. ricordi A. insolitus A. aliniger A. christophei A. distichus A. cybotes A. etheridgei Bio-12 Dr. Joanna  Resource partitioning is differentiation of ecological niches, enabling similar species to coexist in a community Bio-12 Dr. Joanna  Predation Predation (+/− interaction) refers to an interaction in which one species, the predator, kills and eats the other, the prey Some feeding adaptations of predators are claws, fangs, and poison Bio-12 Dr. Joanna  Examples of defensive adaptations in animals (a) Mechanical (b) Chemical defense defense ▶ Porcupine ▶ Skunk (c) Aposematic coloration: warning coloration (d) Cryptic coloration: camouflage ◀ Poison ▶ Canyon dart frog tree frog (e) Batesian mimicry: (f) Müllerian mimicry: A harmless species Two unpalatable mimics a harmful species mimic one. each other. ◀ Yellow jacket ▲ Venomous green parrot snake ◀ Nonvenomous ◀ Cuckoo bee hawkmoth larva Bio-12 Dr. Joanna  Prey display various defensive adaptations Behavioral defenses include hiding, fleeing, forming herds or schools, self- defense, and alarm calls Animals also have morphological and physiological defense adaptations Mechanical and chemical defenses protect species such as porcupines and skunks Bio-12 Dr. Joanna  Herbivory Herbivory (+/− interaction) refers to an interaction in which an herbivore eats parts of a plant or alga It has led to evolution of plant mechanical and chemical defenses and adaptations by herbivores Bio-12 Dr. Joanna  Symbiosis Symbiosis is a relationship where two or more species live in direct and intimate contact with one another Bio-12 Dr. Joanna  Parasitism In parasitism (+/− interaction), one organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process Parasites that live within the body of their host are called endoparasites Parasites that live on the external surface of a host are ectoparasites Bio-12 Dr. Joanna  Many parasites have a complex life cycle involving a number of hosts Some parasites change the behavior of the host in a way that increases the likelihood that the parasite will be transmitted to the next host Parasites can significantly affect the survival, reproduction, and density of their host population Bio-12 Dr. Joanna  Mutualism Mutualistic symbiosis, or mutualism (+/+ interaction), is an interspecific interaction that benefits both species A mutualism can be – Obligate, where one species cannot survive without the other – Facultative, where both species can survive alone Bio-12 Dr. Joanna  Mutualism between acacia trees and ants (a) Hollow thorns that house stinging (b) Area cleared by ants around an ants of the genus Pseudomyrmex acacia tree https://www.youtube.com/watch?v=Xm2qdxVVRm4 – 2 min Amazing Symbiosis: Ant Army Defends Tree Bio-12 Dr. Joanna  Commensalism In commensalism (+/0 interaction), one species benefits and the other is neither harmed nor helped Commensal interactions are hard to document in nature because any close association likely affects both species Bio-12 Dr. Joanna  Facilitation Facilitation (+/+ or 0/+) is an interaction in which one species has positive effects on another species without direct and intimate contact – For example, the black rush makes the soil more hospitable for other plant species Number of plant species With Without Bio-12 Salt marsh with Juncus (foreground) Juncus Juncus Dr. Joanna  Interspecific Interaction Description Interspecific Two or more species compete for a resource competition (−/−) that is in short supply. Predation One species, the predator, kills and eats the (+/−) other, the prey. Predation has led to diverse adaptations, including mimicry. Herbivory An herbivore eats part of a plant or alga. (+/−) Symbiosis Individuals of two or more species live in close contact with one another. Sym- biosis includes parasitism, mutualism and commensalism. Parasitism The parasite derives its nourishment from a (+/−) second organism, its host, which is harmed. Mutualism Both species benefit from the interaction. (+/+) Commensalism One species benefits from the interaction, (+/0) while the other is unaffected by it. Facilitation (+/+ Species have positive effects on the survival or 0/+) and reproduction of other species without the intimate contact of a symbiosis. Bio-12 Dr. Joanna Concept 2: Diversity and trophic structure characterize biological communities In general, a few species in a community exert strong control on that community’s structure Two fundamental features of community structure are species diversity and feeding relationships Bio-12 Dr. Joanna  Species Diversity Species diversity of a community is the variety of organisms that make up the community It has two components: species richness and relative abundance – Species richness is the number of different species in the community – Relative abundance is the proportion each species represents of all individuals in the community Bio-12 Dr. Joanna  Which forest is more diverse? A B C D Community 1 Community 2 A: 25% B: 25% C: 25% D: 25% A: 80% B: 5% C: 5% D: 10% Two communities can have the same species richness but a different relative abundance Bio-12 Dr. Joanna  Communities with higher diversity are – More productive; they produce more biomass (the total mass of all organisms) – More stable in their productivity – Better able to withstand and recover from environmental stresses – More resistant to invasive species, organisms that become established outside their native range Bio-12 Dr. Joanna  Trophic Structure Trophic structure is the feeding relationships between organisms in a community It is a key factor in community dynamics Food chains link trophic levels from producers to top carnivores Bio-12 Dr. Joanna Food Chains Carnivore Quaternary Carnivore consumers Carnivore Tertiary Carnivore consumers Carnivore Secondary Carnivore consumers Herbivore Primary Zooplankton consumers Primary Phytoplankton Plant producers A terrestrial food chain A marine food chain Bio-12 Dr. Joanna  A food web Humans is a Smaller Sperm branching Baleen whales toothed whales whales food chain Crab- Elephant seals eater Leopard with seals seals complex Birds Fishes Squids trophic interactions Carniv- orous plankton Cope- Krill pods Phyto- plankton Bio-12 Dr. Joanna  Each food chain in a food web is usually only a few links long The energetic hypothesis suggests that length is limited by inefficient energy transfer Only about 10% of the energy stored in organic matter at each trophic level is converted to organic matter at the next trophic level – Next lecture Bio-12 Dr. Joanna  Species with a Large Impact Certain species have a very large impact on community structure Such species are highly abundant or play a pivotal role in community dynamics Bio-12 Dr. Joanna  Dominant species are those that are most abundant or have the highest biomass One hypothesis suggests that dominant species are most competitive in exploiting resources Another hypothesis is that they are most successful at avoiding predators Invasive species, typically introduced to a new environment by humans, may become dominant because they lack predators or disease Bio-12 Dr. Joanna  Keystone species exert strong control on a community by their ecological roles, or niches In contrast to dominant species, they are not necessarily abundant in a community Field studies of sea stars illustrate their role as a keystone species in intertidal communities Bio-12 Dr. Joanna  How Wolves Change Rivers https://www.youtube.com/embed/ysa5OBhX z-Q Absent nearly 70 years from the Park, the most remarkable " trophic cascade " occurred. What is a strophic cascade and how exactly do wolves change rivers? Bio-12 Dr. Joanna  Ecosystem engineers (or “foundation species”) cause physical changes in the environment that affect community structure – For example, beaver dams can transform landscapes on a very large scale Bio-12 Dr. Joanna Concept 3: Pathogens alter community structure locally and globally Ecological communities are universally affected by pathogens, which include disease-causing microorganisms, viruses, viroids, and prions Pathogens can be particularly virulent in a new habitat Human activities are transporting pathogens around the world at unprecedented Rates. Community ecology is needed to combat pathogens Bio-12 Dr. Joanna  Community Ecology and Zoonotic Diseases Zoonotic pathogens have been transferred from other animals to humans The transfer of pathogens can be direct or through an intermediate species called a vector Many of today’s emerging human diseases are zoonotic Identifying Lyme disease host species Bio-12 Dr. Joanna Tracking avian flu Bio-12 Dr. Joanna  Chapter Chapter 55 55 Ecosystems and Restoration Ecology Lecture Presentations by Nicole Tunbridge and © 2017 Pearson Education, Inc. Kathleen Fitzpatrick  OUTLINE: Physics in Ecosystems (Ch 55) Energy Budgets and Transfer Biogeochemical Cycles Bio-12 Dr. Joanna Ecosystems at different scales ◀ An island ecosystem ▼ A desert spring ecosystem Bio-12 Dr. Joanna  Transformed to Tundra An ecosystem consists of all the organisms living in a community, as well as the abiotic factors with which they interact A single introduced species can have dramatic effects on both the biotic and abiotic components of an ecosystem Bio-12 Dr. Joanna  Regardless of an ecosystem’s size, its dynamics involve two main processes: energy flow and chemical cycling Energy flows through ecosystems, while matter cycles within ecosystems Bio-12 Dr. Joanna Concept 1: Physical laws govern energy flow and chemical cycling in ecosystems Ecologists study the transformations of energy and matter within ecosystems Bio-12 Dr. Joanna  Conservation of Energy Laws of physics and chemistry apply to ecosystems, particularly energy flow The first law of thermodynamics states that energy cannot be created or destroyed, only transformed Energy enters an ecosystem as solar radiation, is conserved, and is lost from organisms as heat Bio-12 Dr. Joanna  The second law of thermodynamics states that every exchange of energy increases the entropy of the universe In an ecosystem, energy conversions are not completely efficient, and some energy is always lost as heat Bio-12 Dr. Joanna  Conservation of Mass The law of conservation of mass states that matter cannot be created or destroyed Chemical elements are continually recycled within ecosystems In a forest ecosystem, most nutrients enter as dust or solutes in rain and are carried away in water Ecosystems are open systems, absorbing energy and mass and releasing heat and waste products Bio-12 Dr. Joanna An overview of energy and nutrient dynamics in an ecosystem Sun Key Loss Chemical cycling of Energy flow heat Primary producers Primary Detritus consumers Secondary and Microorganisms and other tertiary detritivores consumers Bio-12 Dr. Joanna  Energy, Mass, and Trophic Levels Autotrophs build molecules themselves using photosynthesis or chemosynthesis as an energy source Heterotrophs depend on the biosynthetic output of other organisms Energy and nutrients pass from primary producers (autotrophs) to primary consumers (herbivores) to secondary consumers (carnivores) to tertiary consumers (carnivores that feed on other carnivores) Bio-12 Dr. Joanna  Detritivores, or decomposers, are consumers that derive their energy from detritus, nonliving organic matter Prokaryotes and fungi are important detritivores Decomposition connects all trophic levels Bio-12 Dr. Joanna  Detritivores ▼ Fungi decomposing Detritivores, or a dead tree decomposers, are consumers that derive their energy from detritus, nonliving organic matter. Prokaryotes and fungi are ▲ Rod-shaped and spherical important bacteria in compost (colorized detritivores SEM) Decomposition connects all trophic levels Bio-12 Dr. Joanna Concept 2: Energy and other limiting factors control primary production in ecosystems In most ecosystems, primary production is the amount of light energy converted to chemical energy by autotrophs during a given time period In a few ecosystems, chemoautotrophs are the primary producers Bio-12 Dr. Joanna  Ecosystem Energy Budgets The extent of photosynthetic production sets the spending limit for an ecosystem’s energy budget – money in the energy bank The amount of solar radiation reaching Earth’s surface limits the photosynthetic output of ecosystems Only a small fraction of solar energy actually strikes photosynthetic organisms, and even less is of a usable wavelength Bio-12 Dr. Joanna  Gross and Net Production Total primary production is known as the ecosystem’s gross primary production (GPP) GPP is measured as the conversion of chemical energ