Ecology The study of living organisms in the natural environment, how they interact with one another and how the interact with their nonliving environment
Levels of organization atoms species molecules population organelles cells community ECOLOGY tissues ecosystem organs systems biosphere organism
Species A group of organisms that can reproduce and produce fully fertile offspring Great White Pelican Pelecanusonocrotalus
Population A group of organism of the samespecieswhich live in the same habitat at the same timewheretheycanfreelyinterbreed Habitat: the environment in which a species normally lives or the location of a living organism The black-veined white butterfly (Aporiacrataegi) mating
Community All the populations of the different species living and interacting in the same ecosystem 7-spotted lady bird (Adephagiaseptempunctata) Bean aphids (Aphis fabae) Red ant (Myrmicarubra) Broom plant (Cytisusscoparius)
Ecosystem Community (Biotic) interacting with environment (Abiotic )
Components of an Ecosystem Biotic Factors: living or once living organisms Abiotic Factors: nonliving factors that have an effect on living things Examples: - Water: organisms have water in their bodies (50-95%) and chemical reactions need water to happen. - Soil: type of soil determines which plants and other organisms live in that location - Light and Temperature: affect photosynthesis (plant growth is limited to amount of sunlight) Energy + CO2 + H2O -> C6H12O6 + O2
Energy and Organisms Autotrophs: organisms which can synthesize their own complex, energy rich, organic molecules from simple inorganic molecules (e.g. green plants synthesis sugars from CO2 and H2O; bacteria in deep sea vents doing chemosynthesis) - PRODUCERS Heterotrophs: organisms who must obtain complex, energy rich, organic compounds form the bodies of other organisms (dead or alive). Ex: consumers and decomposers (saprotrophs and detritivores)
Decomposers Detritivores: heterotrophic organisms who ingest dead organic matter. (e.g. earthworms, woodlice, large scavengers). Ingest first, then digest. Saprotrophs: heterotrophic organisms who secrete digestive enzymes onto dead organism matter and absorb the digested material. (e.g. fungi, bacteria). Digest first, then absorb. Earthworm (Lumbricusterrestris) Chanterelle (Cantherelluscibarius)
Consumers Omnivore: eats both plants and animals Carnivore: meat eater Herbivore: plant eater
Food Chains Sequence of relationships between trophic levels. Show the flow of energy from the SUN to the heterotrophs Trophic level: an organism’s feeding position in a food chain Producers: essential to every single food chain
Food Web Shows the feeding relationships in a community. Arrows show the flow of energy.
Read the article and generate a food web: http://ehp.niehs.nih.gov/members/2004/112-8/focus.html
Plant material eaten by caterpillar 200 J 67 J Cellular respiration 100 J Feces 33 J Growth (new biomass) How much is available to the caterpillar’s predator?
Energy and Nutrients Energy enters ecosystems as light and usually leaves as heat. Nutrients do not usually enter an ecosystem and must be RECYCLED. Nutrients include: carbon, nitrogen, phosphorus, magnesium...
The Carbon Cycle
The Nitrogen Cycle
Pyramids of Energy
Biomass Trophic level Dry weight (g/m2) Tertiary consumers Secondary consumers Primary consumers Primary producers 1.5 11 37 809 Amount of dry matter in one organism Each bar represents: dry weight of all organisms in one trophic level
Populations Characteristics: Size: number of individuals at a certain time Density: number of individuals in a certain space at a particular time Spacing: clumped, uniform, random Age Structure Pop. Change = (birth + immigration) – (death + emigration) Limiting factor: prevents the continuing growth of a population in an ecosystem Can be: - water, air, light, food - diseases, competitors, predators, parasites
Population Growth Exponential Phase: population increases exponentially because the natality rate is higher than the mortality rate. Transitional phase: difference between natality and mortality rates are not as great, but natality is still higher so population continues to grow, but at a slower rate. Plateau phase: natality and mortality are equal so the population size stays constant. Carrying Capacity: the maximum population size that can be supported by the environment
The Greenhouse Effect Light from the sun has short wavelengths and can pass through most of the atmosphere. This sunlight warms the earth which in turn emits long wave radiation. This long wave radiation is bounced back by the greenhouse gases, such as carbon dioxide, methane, water vapor, oxides of nitrogen and sulphur dioxide
The Greenhouse Effect Natural and essential to life Human pollution is making it worse = causing global warming Oxides of nitrogen: industrial processes, burning fossil fuels, fertilizers Methane: cattle, waste disposal, natural gas leaks CO2: burning fossil fuels Consequences: Changes in climate = effects on the ecosystem Extinction Melting glaciers = rise in sea level Increase in photosynthetic rates
Changes in atmospheric CO2
Precautionary Principle Action should be taken to prevent harm even if there is not sufficient data to prove that the activity will have severe consequences If people want to do activities that may cause a change in the environment they must prove first it won’t do harm We should take action now: reduce carbon emissions before it’s too late Should people invest money to reduce carbon emissions if we are not 100% sure about the consequences of global warming? More expensive to be eco-friendly What should consumers do?
North America, Greenland, Iceland, Norway, Russia
Example: polar bears/seals/algae affected
Loss of ice habitat
Increased success of pests/pathogens/mosquitoes
Expansion of temperate species/reduced range for arctic species