1. Topic 2 – The Ecosystem
2.1 - Structure
IB Topics

2. Key Words (define and provide a local example of each)
Biotic
Species
Abiotic
Population
Trophic Level
Community
Producer
Habitat
Consumer
Ecosystem
Autotroph
Niche
Heterotroph
Competition
Carnivore
Mutualism
Herbivore
Parasitism
Omnivore
Predation

3. Biotic and Abiotic Components
All living components of the ecosystem
Ex:
All non-living components of the ecosystem
Ex:

4. Food Chains
The position an organism occupies in a food chain is called the trophic level.

7. Local Food Chain Example:
Make your own food chain with Wisconsin species.

8. Food Webs
Ecosystems contain many interconnected food chains

10. Pyramid of Numbers
A graphical model of the number of organisms in a food chain

12. Pyramid of Biomass
A graphical model of the amount of biomass present in a food chain at a certain point in time
***Discuss how biomass is calculated and if its ethical***

13. Pyramid of Productivity
A graphical model of the rate of energy production over time

14. Top Carnivores Bioaccumulation Biomagnification
Toxins (pesticides, etc.) can be retained in fat tissue
Each successive trophic level gains more toxin

15. 2.2 – Measuring Abiotic Components
Topic 2 – The Ecosystem
2.2 – Measuring Abiotic Components
IB Topics

16. Significant Abiotic Factors
Terrestrial Ecosystem
Includes: land
Temperature
Light intensity
Wind speed
SOIL
particle size
moisture
drainage
mineral content
Marine Ecosystem
Includes: Oceans, estuaries, salt marshes and mangroves
salinity
temperature
wave action
dissolved oxygen pH
Freshwater Ecosystem
Includes: lakes, rivers, streams, wetlands
turbidity
temperature
flow velocity pH
dissolved oxygen

17. 2.3 – Measuring Biotic Components
Topic 2 – The Ecosystem
2.3 – Measuring Biotic Components
IB Topics

18. Estimating abundance of organisms
Counting the number of organisms is almost always done using an estimate

19. Lincoln Index A mathematical model to estimate population size
Capture-mark-release-recapture

20. Example 1
Example 2
13 deer were caught and marked
14 deer were caught the second time and 5 were marked
75 Ladybugs were caught and marked
80 Ladybugs were caught the second time and 3 were marked

21. Quadrats
A square of area used to measure the population of non-mobile organisms
Can help to calculate population density and percentage cover

22. Diversity The number of different species
The number of individuals of each species

23. Simpson’s Diversity Index
Used to compare diversity between areas
High value of D implies stable ecosystem
Low value of D implies unstable ecosystem

24. Topic 2 – The Ecosystem
2.4 – Biomes
IB Topics

25. Biomes
A collection of ecosystems that share similar climactic conditions

26. Rainforest
Desert
Tundra
Temperate Forest
Grassland
Prevailing Climate
Location
Sun Exposure
Precipitation
Limiting Factors

27. Varied, where some precip
Rainforest
Desert
Tundra
Temperate Forest
Grassland
Prevailing Climate
Hot, Humid, Rainy
Hot, Dry
Cold
Seasonal
Varied by location
Location
Near Equator
Varied, where no precip
Poles
40-60o N Latitude
Varied, where some precip
Sun Exposure
High
Varied, usually high
Low
Medium, Seasonal
Varied
Precipitation
None
Snow
Limiting Factors
Too much precip.
Not enough water
Too cold, permafrost
Seasons
Low precip

28. Topic 2 – The Ecosystem
2.5 – Function
IB Topics

29. Photosynthesis

30. Respiration

32. Energy Flow Through the Ecosystem

40. Gross Primary Productivity (GPP)
The amount of energy produced by producers

41. Net Primary Productivity (NPP)
The amount of energy stored by producers and available to consumers

42. Gross Secondary Productivity (GSP)
The amount of energy consumed by consumers

43. Net Secondary Productivity (NSP)
The amount of energy stored by consumers and available to the next trophic level

44. Simplified Example:

45. Topic 2 – The Ecosystem
2.6 – Changes
IB Topics

46. Carrying Capacity
The maximum number of organisms an ecosystem can support sustainably over a long period of time

47. Limiting Factors
Factors that limit the amount of individuals in an ecosystem

48. Tolerance
Species will be most abundant within a certain range of a limiting factor

49. Population Curves S Curve J Curve
Reaches carrying capacity and stabilizes
J Curve
Unchecked population growth

50. Limiting Factors Density-dependent factors
Limit population size more as population increases

51. Limiting Factors Density-independent factors
Limit population size regardless of population size

52. K-strategists r-strategists C-strategists Opportunistic species
Inhabit unstable/changing environments
Reproduce early/often, mature quickly
Slow growing/maturing species
Few offspring
Long lifespans
C-strategists
In between r & K

54. Survivorship Curve

55. Succession
A natural increase in the complexity of the structure and species composition over time

58. Succession Primary Secondary
Occurs where a previous community has been destroyed
Occurs on uncolonized substrate (rock)

60. Zonation
Different types of ecosystems in a gradient due to elevation or resources
Ex: Altitude zonation on a mountain

62. Climax Community
A stable, complex ecosystem in a late stage of succession
Characteristics:

63. Topic 2 – The Ecosystem
2.7 – Measuring Changes
IB Topics

64. Environmental Impact Assessment
Before any development gets permission to begin, an EIA must be done
Predicts the potential impacts on habitats, species, and ecosystems

67. Baseline Study Habitat type Species list Species diversity
Endangered species
Land use
Hydrology
Human population
Soil quality