Keystone Species

2 min talks on keystone species

Homework

1. Discuss the trade-off between use of DDT and control of malaria

2. Discuss marine plastic debris and the effect on Laysan Albatrosses

THIS MEANS YOU NEED TO FINISH THE BOOKLET FOR WEDNESDAY NEXT WEEK

Understandings, Applications and Skills

Statement GuidanceC.3.U1 Introduced alien species can escape into local ecosystems and become invasive.

C.3.U2 Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive.

C.3.U3 Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification.

C.3.U4 Macroplastic and microplastic debris has accumulated in marine environments.

C.3.A1 Study of the introduction of cane toads in Australia and one other local example of the introduction of an alien species.

C.3.A2 Discussion of the trade-off between control of the malarial parasite and DDT pollution.

C.3.A3 Case study of the impact of marine plastic debris on Laysan albatrosses and one other named species.

C.3.S1 Analysis of data illustrating the causes and consequences of biomagnification.

C.3.S2 Evaluation of eradication programmes and biological control as measures to reduce the impact of alien species.

Understandings, Applications and Skills

Statement GuidanceC.3.U1 Introduced alien species can escape into local ecosystems and become invasive.

C.3.U2 Competitive exclusion and the absence of predators can lead to reduction in the numbers of endemic species when alien species become invasive.

C.3.U3 Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification.

C.3.U4 Macroplastic and microplastic debris has accumulated in marine environments.

C.3.A1 Study of the introduction of cane toads in Australia and one other local example of the introduction of an alien species.

C.3.A2 Discussion of the trade-off between control of the malarial parasite and DDT pollution.

C.3.A3 Case study of the impact of marine plastic debris on Laysan albatrosses and one other named species.

C.3.S1 Analysis of data illustrating the causes and consequences of biomagnification.

C.3.S2 Evaluation of eradication programmes and biological control as measures to reduce the impact of alien species.

C.3.U3 Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification.

Norwegian killer whales most toxic mammals in Arctic

http://wwf.panda.org/?53520/norwegian-killer-whales-most-toxic-mammals-in-arctic

What is this?To which

vertebrate group does it

belong?Where does it come from?

What is this?

To which vertebrate

group does it belong?

Where does it come from?

Mass die off of Gharial Crocodiles

Skim read the article below to find the reason for the mass die off of these crocs

•http://news.bbc.co.uk/1/hi/sci/tech/7755393.stm

C.3.U3 Pollutants become concentrated in the tissues of organisms at higher trophic levels by biomagnification. http://youtu.be/DxqDaTUh08o

https://www.youtube.com/watch?v=E5P-UoKLxlA https://www.youtube.com/watch?v=DxqDaTUh08o

(a)Define the term biomagnification. (1)(b) Outline one example of biomagnification. (3)(Total 4 marks)

C.3.S1 Analysis of data illustrating the causes and consequences of biomagnification.

First read the essay on the biomagnification of DDT and the effect on Peregrine Falcons (Falco peregrinus): http://web.stanford.edu/group/stanfordbirds/text/essays/DDT_and_Birds.html

1. In the 1950’s, why was DDT originally being sprayed?2. Which bird species was the first for numbers to fall?3. What happens to organic pesticides as they pass through the food chain4. Which bird species would suffer from the highest levels of pesticides5. Draw a generalized food chain using the examples given6. What two reasons account for the accumulation of pesticides in top level

predators7. How is it that DDT reduces the population of brown flacons and bald

eagles?8. What new problems has the ban on DDT caused

C.3.S1 Analysis of data illustrating the causes and consequences of biomagnification.

Key dates:1955 – DDT use as a pesticide becomes widespread in the US1972 – DDT usage in the US is banned

http://www2.ucsc.edu/scpbrg/Images/Peregrines/crushedegg.jpghttp://www.nps.gov/yuch/naturescience/images/PeregrineAdultWithChicks.jpg

http://www.fws.gov/contaminants/images/DDT.jpg

Biomagnification of DDT in a different predatory bird

C.3.S1 Analysis of data illustrating the causes and consequences of biomagnification.

https://sites.google.com/site/peregrinefalconcp2014/endangered-species

http://www.nps.gov/yuch/naturescience/images/PeregrineAdultWithChicks.jpg

Analysis questions:

1.Describe the trend shown by the data.

2.Deduce the strength of the correlation

3.Evaluate the limitations of the data in supporting the link between DDT and the decrease in Peregrine Falcons.

C.3.S1 Analysis of data illustrating the causes and consequences of biomagnification.

http://jan.ucc.nau.edu/~doetqp-p/courses/env440/env440_2/lectures/lec25/lec25.html

http://www.nps.gov/yuch/naturescience/images/PeregrineAdultWithChicks.jpg

Analysis questions:

4.Describe the trend shown by the data in relation to the use of DDT

5.Estimate the percentage change in egg shell thickness between 1950 and 1958

6.Suggest why the range of egg shell thickness increased after 1966.

C.3.S1 Analysis of data illustrating the causes and consequences of biomagnification.

http://jan.ucc.nau.edu/~doetqp-p/courses/env440/env440_2/lectures/lec25/lec25.html

http://www.nps.gov/yuch/naturescience/images/PeregrineAdultWithChicks.jpg

Analysis questions:

7.Describe the correlation between DDE and egg shell thickness. [1]

8.Evaluate the limitations of the data supporting the link between DDT and egg shell thickness in Peregrine Falcons.

9.Explain why egg shell thickness is correlated with sightings of Peregrine Falcons

C.3.A2 Discussion of the trade-off between control of the malarial parasite and DDT pollution.

Sources of DDT•DDT in soil can be absorbed by some growing plants and by the animals or people who eat those plants•DDT in water is absorbed by fish and shellfish in those waterways•Atmospheric deposition•Soil and sediment runoff•Improper use and disposal

http://www.epa.gov/pbt/pubs/ddt.htm

What is DDT (dichlorodiphenyltrichloroethane)?Prior to 1972 when its use was banned (in the US), DDT was a commonly used pesticide.

What is it used for now?Some parts of the world continue to use DDT in disease-control programs.

Why Are We Concerned About DDT?Even though DDT has been banned since 1972, it can take more than 15 years to break down in our environment.

What harmful effects can DDT have on us?•Human carcinogen (e.g. liver cancer)•Damages the liver•Temporarily damages the nervous system (damages developing brains)•Reduces reproductive success (lower fertility and genital birth defects)•Damages reproductive system

How are we exposed to DDT?•By eating contaminated fish and shellfish•Infants may be exposed through breast milk•By eating imported food directly exposed to DDT•By eating crops grown in contaminated soil

C.3.A2 Discussion of the trade-off between control of the malarial parasite and DDT pollution.

http://www.npr.org/templates/story/story.php?storyId=6083944

http://www.scientificamerican.com/article/ddt-use-to-combat-malaria/

http://www.telegraph.co.uk/news/science/science-news/10600234/Banned-pesticide-DDT-may-raise-risk-of-Alzheimers-disease.html

C.3.A2 Discussion of the trade-off between control of the malarial parasite and DDT pollution.

Pros Cons

“DDT should really be the last resort against malaria, rather

than the first line of defense” http://www.scientificamerican.com/article/ddt-use-to-combat-malaria/

Use the articles on the previous page to discuss the use of DDT to control malaria