Ecology

1. Ecology IB Biology Modified from Fernanda Silva – Teacher at Chapel School

2. Ecology • The study of living organisms in the natural environment, how they interact with one another and how the interact with their nonliving environment

3. Levels of organization atoms species molecules population organelles cells community ECOLOGY tissues ecosystem organs systems biosphere organism

4. Species • A group of organisms that can interbreed and produce fertileoffspring. Great White Pelican Pelecanusonocrotalus

5. 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

6. 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)

7. Ecosystem • Community (Biotic) interacting with environment (Abiotic )

8. 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

9. 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)

10. 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)

11. Consumers • Omnivore: eats both plants and animals • Carnivore: meat eater • Herbivore: plant eater

13. 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

14. Food Web • Shows the feeding relationships in a community. Arrows show the flow of energy.

15. Generate a food web: http://coolclassroom.org/cool_windows/home.html

17. 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?

18. 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...

19. The Carbon Cycle

20. The Nitrogen Cycle

21. Pyramids of Energy

22. Trophic level Dry weight (g/m2) Tertiary consumers Secondary consumers Primary consumers Primary producers 1.5 11 37 809 Biomass • Amount of dry matter in one organism • Each bar represents: dry weight of all organisms in one trophic level

23. Populations • Factors that affect population size: • Natality: the number of new members of the species due to reproduction • Mortality: the number of deaths • Immigration: members arriving from other places • Emigration members leaving the population • Pop. Change = (natality + immigration) – (mortality + emigration)

24. 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

25. Factorsthatlimitthegrowth of a population • Limiting factors: prevents the continuing growth of a population in an ecosystem

26. 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

27. 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

28. Sources of CO2 There are fourmain 'pools' of carbon in theenvironment: • Atmosphere     • Biosphere     • Sediments  • Ocean There are a number of processesbywhichcarbon can be cycledbetweenthese pools: • Photosynthesis:Atmosphericcarbondioxideis removed and fixed as organiccompounds (e.g. sugars) • Feeding:  In whichorganiccarbonis moved fromonetrophicleveltothenext in a foodchain • Respiration:Allorganisms (includingplants) metaboliseorganiccompoundsforenergy, releasingcarbondioxide as a by-product • Fossilization:  In whichcarbonfrompartiallydecomposeddeadorganismsbecomestrapped in sediment as coal, oil and gas (fossilfuels)  • Combustion:Duringtheburning of fossilfuels and biomass • In oceans, carbon can be reversiblytrapped and stored as limestone (storagehappens more readily at lowtemperatures)

29. Changes in atmospheric CO2

30. Changes in atmospheric CO2 Vostok Ice Core Data - CO2 vs Temperature (last 400,000 years)

31. Precautionary Principle SL pg. 137 • 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?

32. ArticEcosystems: • North America, Greenland, Iceland, Norway, Russia • Loss of ice  more ice is melting every year • Climate change  conveyor system is affected • Rise in sea levels • Melting of permafrost • Increased decomposition  CO2 and methane released into the atmosphere • Increased success of pests/pathogens/mosquitoes • Expansion of temperate species/reduced range for arctic species • polar bears/seals/algae affected • Disturbance of food chains

33. Sources: • http://www.sciencescene.com/Environmental%20Science/02TheEnvironment&Ecosystems/Successtion/Pond%20C.jpg