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
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3. Levels of Ecological Organization
Individual ( A Moose)
Level 2
Population (Herd of Moose)
Level 3
Community: (Herd + Birds + Squirrels + etc
Level 4
Ecosystem : Living + nonliving components in the environment

4. Examples of Ecosystems:
Forest
Lake
Aquarium
Island

5. Interactions within Ecosystems
1 .1
Interactions within Ecosystems
Trophic Relationships The feeding connections among the living organisms in an ecosystem (a food chain) ST
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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
Matter that is not necessarily produced by living organisms. (e.g. Water, mineral salts, carbon dioxide)
Organic
Matter that enters into the composition of living organisms and that is usually created by them.
(e.g. proteins, carbohydrates, fats)

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 – organisms that feed on the waste and remains of other living organisms.
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

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
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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. Flow of inorganic matter
Chemical Recycling
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. Biomass and Primary Productivity in Ecosystems
1 .3
Biomass and Primary Productivity in Ecosystems
Biomass – the total mass of organic matter in an ecosystem at any given time. ST
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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
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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
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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
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25. Ecological Succession
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
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26. A forest recovering after acid rain

27. Ecological Footprints
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. Contaminants – is any type of substance or radiation that is likely to cause harm to one or more ecosystems.
3.1
Class of contaminants
Examples
Inorganic
Lead, arsenic, mercury, nitrogen oxides, phosphorus
Organic
Insecticides, pesticides, benzene,
polychlorinated biphenyls (PCBs)
Microbial
Viruses and harmful bacteria
Radioactive
Uranium, plutonium, radon
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

34. Bioaccumulation and Bioconcentration of Contaminants
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

35. Bioconcentration (also called Biomagnification or Bioamplification)- the concentration of a contaminant in the tissues of living organisms tends to increase with each trophic level.

38. 4
Biotechnology
Biodegradation – the breaking down of organic matter into inorganic matter by microorganisms
EST

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

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

41. 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

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

43. 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)