Bright blue marble floating in space Ecology
Earth s biomes
Environmental factors Abiotic factors non-living chemical & physical factors temperature light water nutrients Biotic factors living components animals plants
Marine benthos coral reef intertidal
Tropical rainforest distribution: equatorial precipitation: very wet temperature: always warm characteristics: many plants & animals, thin soil
Savanna distribution: equatorial precipitation: seasonal, dry season/wet season temperature: always warm characteristics: fire-adapted, drought tolerant plants; herbivores; fertile soil
Desert distribution: 30 N & S latitude band precipitation: almost temperature: variable daily & seasonally, hot & cold characteristics: sparse vegetation & animals, cacti, succulents, drought tolerant, reptiles, insects, rodents, birds
Temperate Grassland distribution: mid-latitudes, mid-continents precipitation: seasonal, dry season/wet season temperature: cold winters/hot summers characteristics: prairie grasses, fire-adapted, drought tolerant plants; many herbivores; deep, fertile soil
Temperate Deciduous Forest distribution: mid-latitude, northern hemisphere precipitation: adequate, summer rains, winter snow temperature: moderate warm summer/cool winter characteristics: many mammals, insects, birds, etc.; deciduous trees; fertile soils
Coniferous Forest (Taiga) distribution: high-latitude, northern hemisphere precipitation: adequate to dry (temperate rain forest on coast) temperature: cool year round characteristics: conifers; diverse mammals, birds, insects, etc.
Arctic Tundra distribution: arctic, high-latitude, northern hemisphere precipitation: dry temperature: cold year round characteristics: permafrost, lichens & mosses, migrating animals & resident herbivores
Alpine Tundra distribution: high elevation at all latitudes precipitation: dry temperature: cold year round characteristics: permafrost, lichens, mosses, grasses; migrating animals & resident herbivores
Chapter 52 Population Ecology
Changes to population size Adding & removing individuals from a population birth death immigration emigration
Growth rate Exponential growth characteristic of a population without limiting factors ex. introduced to a new environment Whooping crane coming back from near extinction African elephant protected from hunting
Carrying capacity Can populations continue to grow exponentially? of course NOT! what sets limit? resources, predators, parasites Carrying Capacity (K) maximum population size that environment can support with no degradation of habitat not fixed; varies with changes in resources
Model of growth Decrease in rate of growth as reach carrying capacity
Different life strategies K-selection r-selection K-selection mortality constant r-selection
Reproductive strategies K-strategy have few offspring & invest a lot of energy in raising them to reproductive age primates coconut r-strategy have many offspring & invest little in their survival insects dandelion & other weeds
Predator prey interactions Population cycles
Age structure Relative number of individuals of each age What do the data imply about population growth in these countries?
Human population What factors have contributed to this exponential growth pattern? 2005 6 billion Is the human population reaching carrying capacity? 1650 500 million
Chapter 53 Community Ecology
Inter-species interactions Symbiotic interactions competition (-/-) compete for limited resource 2 species cannot coexist in a community if their niches are identical predation / parasitism (-/+) mutualism(+/+) lichens (algae & fungus) commensalism (+/0) barnacles attached to whale
(+/+) mutualism commensalism (+/0) predation (+/-) (-/-) competition
Niche An organism s niche is its ecological role habitat = address, niche = job Resource partitioning
Niche & competition Competitive Exclusion No two similar species can occupy the same niche at the same time
Predation drives evolution Predators adaptations locate & subdue prey Prey adaptations elude & defend horns, speed, coloration spines, thorns, toxins
Trophic structure Food chains feeding relationships food chain usually 4 or 5 links = trophic levels length of food chain limited by inefficiency of energy transfer
Energy transfer Energy in from the Sun captured by autotrophs = producers (plants) Energy through food chain transfer of energy from autotrophs to heterotrophs (herbivores to carnivores) heterotrophs = consumers herbivores carnivores
Energy inefficiency incomplete digestion metabolism
Pyramids of production represent the loss of energy from a food chain how much energy is turned into biomass
Food webs Food chains are hooked together into food webs Who eats whom? a species may weave into web at more than 1 trophic level bears there s always a bigger fish What limits the length of AP a Biology food chain?
Implications Dynamics of energy through ecosystems have important implications for human populations what food would be more ecologically sound?
Disturbances Most communities are in a state of change due to disturbances fire, weather, human activities, etc. not all are negative
Disturbances Disturbances are often necessary for community development & survival
Ecological cycle fire as part of a natural community cycle
Ecological succession The sequence of community changes after a disturbance transition in species composition over ecological time years or decades Mt. St. Helens
Succession Change in species mix over time From bare soil, then bacteria lichens & mosses grasses shrubs trees make soil{
Succession from mosses & lichens = pioneer species to shrubs & trees
Climax forest The species mix of climax forest is dependent on the abiotic factors of the region solar energy levels temperature rainfall fertility & depth of soil birch, beech, maple, hemlock
Chapter 54 Ecosystems
Ecosystem Community of organisms plus the abiotic factors that exist in a certain area
Nutrient cycling Decomposition connects all trophic levels
Carbon cycle CO 2 in atmosphere Diffusion Respiration Photosynthesis Combustion of fuels Industry and home Plants Animals Dissolved CO2 Bicarbonates Photosynthesis Animals Plants and algae Deposition of dead material AP Carbonates Biology in sediment Deposition of dead material Fossil fuels (oil, gas, coal)
Nitrogen cycle Carnivores Atmospheric nitrogen Herbivores Plankton with nitrogenfixing bacteria Birds Fish Excretion Loss to deep sediments Plants Nitrogenfixing Death, excretion, feces bacteria Decomposing bacteria (plant roots) Amino acids Nitrogenfixing Ammonifying bacteria bacteria Nitrifying bacteria (soil) Denitrifying Soil nitrates bacteria
Phosphorus cycle Loss in drainage Plants Decomposers (bacteria and fungi) Animal tissue and feces Phosphates in solution Land animals Soluble soil phosphate Aquatic animals Urine Rocks and minerals Animal tissue and feces Plants and algae Decomposers (bacteria and fungi) Precipitates Loss to deep sediment
What have we done!
Impact of ecology as a science Ecology provides a scientific context for evaluating environmental issues Rachel Carson, in 1962, in her book, Silent Spring, warned that use of pesticides such as DDT was causing population declines in many non-target organisms
Barry Commoner s Laws of Ecology Everything is connected to everything else Everything must go somewhere there is no such place as away Nature knows best There is no such thing as a free lunch Laws of Unintended Consequences
Acid Precipitation nitrogen oxides sulfur dioxide power plants industry transportation
Acid rain
BioMagnification
BioMagnification PCBs General Electric manufacturing plant on Hudson River PCBs in sediment striped bass nesting areas
Carbon Dioxide Global Warming
CO 2 NO x methane
Ozone Depletion protects from UV rays
Ozone Depletion
Bad ozone vs. good ozone
Ozone Depletion Loss of ozone above Antarctica
Deforestation Loss of habitat Loss of biodiversity
Loss of Diversity 3 levels of biodiversity ecosystem diversity mix of species in community genetic diversity within population All decreased by human activity loss of genetic diversity loss of biodiversity
Driven to extinction
Introduced species Introduced species transplanted populations grow exponentially in new area non-native species out-compete native species lack of competitors & predators reduce diversity examples African honeybee gypsy moth zebra mussel purple loosestrife gypsy moth kudzu
Zebra mussel ~2 months
Purple loosestrife
Purple loosestrife Non-native species out-compete native species lack of competitors & predators reducing diversity causing loss of food & nesting sites for animals 1968 1978
Overexploitation North Atlantic bluefin tuna
Fragmented habitat
Biodiversity hot spots
Restoration projects
Think Globally, Act Locally