The Living World: Ecosystems (Chapter 10)

1. The Living World:Ecosystems (Chapter 10)

2. 1 Ecosystem – A community of living organisms interacting with one another and with the nonliving components of the environment they inhabit. ST EST AST

3. Levels of Ecological Organization

4. Examples of Ecosystems: • Forest • Lake • Aquarium • Island

5. 1 .1 Interactions within Ecosystems Trophic Relationships The feeding connections among the living organisms in an ecosystem (a food chain) ST EST AST

6. Simple food “chain”

7. More realistic food “web”

8. Producers– autotrophic (self nourish) organisms with the ability to create organic matter from inorganic matter in an ecosystem through photosynthesis. Plants use sunlight to make sugars for energy. Plants Phytoplankton (algae)

9. Inorganic vs. organic matter

10. Consumers – heterotrophic (other nourishment) organisms that feed on other living organisms and/or their products such as eggs, fruit etc.

11. Consumers • First order (or primary) consumers: feed on producers (eg: a deer eats grass, birds eat seeds). They are herbivores. • Second order consumers: feed on first order consumers (eg: a wolf eats a deer, a cat eats a bird). They are carnivores. • Third order consumers: feed on second order consumers • Fourth order consumers: feed on third order consumers etc. etc.

12. Omnivores: • Consumers that eat several orders at once. (eg: bears eat berries and fish, humans eat grain and meat).

13. Decomposers are detritivores which are heterotrophs that can be eaten by consumers Feed on detritus which is dead organic matter such as fallen leaves, dead wood, animal remains, etc Examples are: worms, some bacteria, certain insects such as the sow bug Decomposers – organisms that feed on the waste and remains of other living organisms.

14. Trophic Network – Food Web

15. 1 .2 Ecosystem Dynamics Material and Energy Flow – the exchange of matter and energy between the living organisms in an ecosystem and between those organisms and their environment. Law of conservation of Mass – nothing is loss and nothing is created; Matter is transformed ST EST AST

16. Material Flow and Chemical Recycling Chemical recycling – is a natural phenomenon by which decomposers make inorganic matter available in an ecosystem by breaking down organic matter.

17. ChemicalRecycling Decomposers Detritus Consumers Producers Flow of inorganic matter Environment Flow of organic matter

18. Energy Flow: the sun is the main source of energy for ecosystems Thermal energy lost in the environment Radiation energy Primary Consumer Secondary Consumer Producer

19. 1 .3 Biomass and Primary Productivity in Ecosystems Biomass – the total mass of organic matter in an ecosystem at any given time. ST EST AST

20. Primary productivity of an ecosystem is the amount of new biomass generated by its producers Factors that affect primary productivity are: • Light (radiation energy) from the sun • Amount of water (necessary for photosynthesis) • Essential nutrients (carbon, nitrogen, phosphorus, and potassium) • Temperature – weather promotes growth of producers

21. 2 Disturbances A disturbance is an event that damages an ecosystem. It can lead to the elimination of organisms and alter the availability of resources. E.g. flooding, storms, oil spills, volcanic eruptions ST EST AST

22. 2.1 Natural Disturbances Events triggered by environmental phenomena rather than humans but can be very damaging nonetheless. (storm churning waters = surface + subsurface waters to mix) E.g. volcanic eruptions, drought, flood, forest fires, frost, freeze rain & heat waves ST EST AST

23. 2.2 Human Disturbances Humans and their actions are a major threat to ecosystems from individual acts like littering to large scale projects. E.g. logging, mining, oil spills, housing projects, industries, pollution, etc. ST EST AST

25. 2.3 Ecological Succession Ecological succession – the series of changes that occur in an ecosystem after a disturbance and that continue until the balance of the ecosystem is restored. ST EST AST

26. A forest recovering after acid rain

27. 2.4 Ecological Footprints Ecological footprints are estimates of the surface area individual humans or populations require to obtain the resources for satisfying all their needs and to ensure the disposal of their waste. Land & water used to produce goods Land & water used to dispose of waste Ecological Footprint Land & water occupied = + + EST

28. Ecological Carrying Capacity

29. 3 Ecotoxicology is the study of the ecological consequences of polluting the environment with various substances and radiation, released by human activity. EST SE

30. 3.1 Contaminants – is any type ofsubstance or radiation that is likely to cause harm to one or more ecosystems. EST SE

31. Toxicity Toxicity of each contaminant depends of the following three factors: • Concentration – more concentrated higher the risk • Type of organism it comes in contact with • Length of exposure

32. Toxicity threshold – the level of concentration above which a contaminant causes one or more harmful effects in an organism LD50 – indicator used to determine toxicity dose that is lethal to 50% of individuals

33. 3.2 Bioaccumulation and Bioconcentration of Contaminants Bioaccumulation – the tendency among certain contaminants to accumulate over time in the tissues of living organisms. EST SE

34. Bioconcentration – a phenomenon by which the concentration of a contaminant in the tissues of living organisms tends to increase with each trophic level.

35. 4 Biotechnology Biodegradation – the breaking down of organic matter into inorganic matter by microorganisms EST

36. Bioremediation – a biotechnology for cleaning up a polluted site, using microorganisms that decompose the contaminants.

37. Phytoremediation – a biotechnology that uses plants or algae to eliminate contaminants from a site.

38. Wastewater Treatment Wastewater – water that is discharged after household or industrial use and that is polluted as a result of human activities. Wastewater can contain: • Sand or other particles • Pathogens • Nutrients that stimulate the excessive growth of algae • Chemicals

39. Two main methods for treating wastewater are: Septic Tanks and Wastewater Treatment plants

40. Checkup • Pg 342 # 1-15, A and C ST and AST • Pg 342 # 1-26, A - C EST • Pg 342 # 18-23, B SE • Eco-sketch Complex Task (ST & AST) • Pg 323 – Vermicomposting from cafeteria (optional)

41. References • Observatory the Environment – Cyr, Forget, Verreault – 2009, ERPI • Google Images