Essential Idea
Human activities impact on ecosystem function.
Understandings
Introduced alien species can escape into local ecosystems and become invasive.
Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive.
Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification.
Macroplastic and microplastic debris has accumulated in marine environments.
Applications
Study of the introduction of cane toads in Australia and one other local example of the introduction of an alien species.
Discussion of the trade-off between control of the malarial parasite and DDT pollution.
Case study of the impact of marine plastic debris on Laysan albatrosses and one other named species.
Skills
Analysis of data illustrating the causes and consequences of biomagnification.
Evaluation of eradication programmes and biological control as measures to reduce the impact of alien species.
Key Vocabulary
Endemic species
Introduced (alien) species
Invasive species
Cane toads
Biological control
Competitive exclusion
Biomagnification
DDT
Macro & microplastic debris
Laysan albatrosses (Midway Island birds)
Textbook Reading and/or Activities
Click HERE for a pdf of chapter 9.
Pages 462-476
TOK (p.464)
Worked Example (p.466-467)
Worked Example (p.468)
Challenge Yourself (p.472)
Challenge Yourself (p.473-475)
Exercises (p.476)
Notes
C.3 Impacts of Humans on Ecosystems
A detailed set of notes, prepared by Bob Smullen, examining U1-U4, A1-A3 and S1-S2.
A detailed set of notes, created by Stephen Taylor, examining U1 - U3, A1 and S1 - S2.
A detailed set of notes, created by Chris Paine, examining all of the IB learning expectations.
A series of questions, prepared by Bob Smullen, to help check your understanding of both Topic 4 and Option C based on Ecology. This is VERY GOOD practice.
Learning Activities
Chi-Squared Test
This activity, prepared for the American Statistical Association, will help you better understand how to determine whether or not a statistically significant difference exists between two data sets.
Supplemental Reading
Abiotic vs. Biotic
This reading (<15 mins), prepared by Diffen, clearly outlines the differences between abiotic and biotic components of the environment. It includes a relevant SlideShare and two videos to help clarify each concept.
This video outlines the plastic pollution issue and how it is impacting the most remote corners of our planet.
This video outlines the impact of the invasive cane toads in Australia that were brought to the country intentionally but have had some unforeseen consequences.
This video uses several examples to outline what invasive species are and how they threaten native populations.
Must Watch Videos
Should Watch Videos
This video pokes a little fun at the idea of invasive species but also illustrates the severity of their impact on local ecosystems.