Understanding Competitive Exclusion in Ecosystems

1. Mr A Lovat Which principle does this demonstrate?

3. Wordwall or Crossword Fundamental / The type of niche that an organism will occupy if there is no outside source of competition (1) Realised / The type of niche that an organism will occupy when another species is in competition with it (1) Resource partitioning / A way to divide up resources to ensure two species in competition don’t become extinct (2) Competitive exclusion / A principle to explain why when two species are in direct completion one goes extinct (2) Grey squirrel / A species that is in danger in England due to a larger and better adapted competitor being introduced by people in the early 1900s (2) Zone of stress / Range of conditions in which an organism may die if zone of tolerance not returned to normal (3) Zone of tolerance / Range of conditions in which an organism can tolerate (3) Zooxanthellae / The symbiotic photosynthetic organism found within coral species (1) Symbiotic / Organisms that are reliant on another to the point that one cannot survive without the other (may be endosymbiotic) (1) Coral bleaching / Name of the process in which corals lose their syumbiotic zooxanthellae (2)

4. Homework • Collect in ‘Interactions of animals’ summary • Remember, 2 min talk on keystone species tomorrow • Use the ISSG website to research an invasive species and evaluate current methods being used to control their numbers

5. 11th hour http://www.imdb.com/title/tt0492931/ https://www.youtube.com/results?search_query=the+11th+hour https://www.youtube.com/watch?v=C14-SrSv270

6. C.3Impacts of humans on ecosystems Essential idea: Human activities impact on ecosystem function. Rhododendrons are beautiful eye catching shrubs that grow in many gardens throughout the world. Rhododendrons are native to alpine regions in Asia. Since their introduction to non-native regions they become an invasive species causing major disruptions to ecosystems, e.g. in Western Europe they have out-competed local woodland plants causing major reductions in local biodiversity.

7. Understandings, Applications and Skills

8. Understandings, Applications and Skills

9. Human Impacts on ecosystems Watch Leonardo Di Caprio’s message (below) before watching his very poignant movie “The 11th Hour” The WWF and UNEP links gives more information about the issues and what can and is being done to solve problems http://youtu.be/9OhdMULRkAs http://freedocumentaries.org/documentary/the-11th-hour http://www.unep.org/wed/ http://www.worldwildlife.org/

10. What is an alien species? Do you know of any that you come across in your everyday life?

11. Zebra Mussel

12. Harlequin ladybird

13. Cane Toad Don’t mess with me

14. Tilapia

15. Rabbits

17. Emerald Ash Borer

20. C.3.U1 Introduced alien species can escape into local ecosystems and become invasive. Can you think of an invasive alien species that has caused problems in England?

21. Understandings, Applications and Skills

22. They occupy a similar neiche… why cant they both survive?

23. 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. Competitive exclusion principle: Two species cannot occupy the same niche in a community, as there will be competition for the same resources. When one species has even the slightest advantage or edge over another then the one with the advantage will dominate. Advantages can come in different forms, 5 examples of advantages between species occupying similar niches are: High reproductive rate Larger size / more aggressive Faster / more efficient forager Absence of predator Invasive species often lack a predator, due to being in a foreign environment. In the case of invasive plants this can mean an absence of suitable herbivores.

24. The Super Squirrel

25. 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. Differences? Why is the grey squirrel a better competitor?

26. Grey squirrels are better at obtaining food sources AND eat a wider variety of foods

27. 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. In Britain and in Ireland, the eastern gray squirrel is not regulated by natural predators.[31] This has aided its rapid population growth and has led to the species being classed as a pest. Measures are being devised to reduce its numbers, including one plan for celebrity television chefs to promote the idea of eating the squirrels.[32] In areas where relict populations of red squirrel survive, such as the islands of Anglesey and Brownsea, programs exist to eradicate gray squirrels in an effort to allow red squirrel populations to recover.[33] Although complex and controversial, the main factor in the eastern gray squirrel's displacement of the red squirrel is thought to be its greater fitness and, hence, a competitive advantage over the red squirrel on all measures.[34] The eastern gray squirrel tends to be larger and stronger than the red squirrel and has been shown to have a greater ability to store fat for winter.  https://www.youtube.com/watch?v=_ukJF2b82SU http://en.wikipedia.org/wiki/Eastern_gray_squirrel

28. 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. • Competition • Displacement of red squirrels • Competitive exlcusion?

29. 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. • Compare the distribution of grey and red squirrels between 1945 and 2010 [3] • Suggest a reason for the trend [2] • Suggest what may happen to native populations of red squirrels if this trend is not reversed [1] • Suggest a method to control the number of grey squirrels to allow the reds to recover [1]

30. 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. Compare the distribution of grey and red squirrels between 1945 and 2010 [2] Red squirrels start with high distribution throughout UK whereas greys only found in central southern parts; Grey squirrel increase in distrubtion while reds decrease Grey squirrels dominate England while reds are isolated in northern parts by 2010; Always few areas of overlap between the two species; No red of grey squirrels ever found in northern Scotland/western Ireland; 2. Suggest a reason for the trend [2] Grey squirrels outcompeting reds/better able to obtain resources Both species occupy a similar niche Competitive exclusion/no two species can occupy the same ecological niche 3. Suggest what may happen to native populations of red squirrels if this trend is not reversed [1] Extinction/Competitive exclusion 4. Suggest a method to control the number of grey squirrels to allow the reds to recover [1] Killing or trapping them/sterilisation/biological control that does not effect reds/ forestry management to plant trees favourable to the reds etc

31. Understandings, Applications and Skills

32. Cane Toad Don’t mess with me

33. An example where biological control failed • Cane toad was introduced to Australia to combat the French Cane beetle and Grey back cane beetle. However, the cane toad thrived and started to feed on other insects. It took over other native amphibian habitats and brought foreign diseases to reptiles. • They contain a poison in glands in their shoulders and are poisonous to crocodiles, tiger snakes and dingoes. This is an example where new introduced organisms can have a catastrophic effect on an ecosystem.

34. Biological control for cane toads (viruses/parasites etc) is under development • Biological control of cane beetle – didn’t work as ate other species of insect too… • Competition with native amphibians • Toxins poison local predators (disrupt food chain) • Possible extinctions?

35. C.3.A1 Study of the introduction of cane toads in Australia and one other local example of the introduction of an alien species. http://youtu.be/t3ENUqV5-bw http://youtu.be/gX1FLXEo96g

36. Cane toad • http://news.bbc.co.uk/1/hi/world/asia-pacific/7970877.stm • https://maps.google.co.uk/maps?hl=en&tab=wl • https://www.youtube.com/watch?v=OtMtIItimjQ

37. Rabbits in Australia C.3.A1 Study of the introduction of cane toads in Australia and one other local example of the introduction of an alien species. • http://www.animalcontrol.com.au/rabbit.htm NOT TO BE COVERED IN LESSON • No natural predators • Millions of dollars of crop damage Read the article: http://theconversation.com/rabbits-and-biological-control-two-unexpected-christmas-presents-11399

38. Control of Invasive Species RHDV as a form of biological control NOT TO BE COVERED IN LESSON

39. C.3.S2 Evaluation of eradication programmes and biological control as measures to reduce the impact of alien species. NOT TO BE COVERED IN LESSON

40. C.3.S2 Evaluation of eradication programmes and biological control as measures to reduce the impact of alien species. http://www.issg.org/database/welcome/ HOMEWORK for Friday Research one invasive species and evaluate the management strategies put in place to control their numbers

41. Bouvet Island Read the article on a place with no invasive species • http://www.newscientist.com/article/mg19426081.600-the-last-place-on-earth-with-no-invasive-species.html?full=true&print=true • https://maps.google.co.uk/maps?q=Bouvet+Island&bav=on.2,or.r_qf.&bvm=bv.45512109,d.d2k&biw=1024&bih=571&wrapid=tlif136662317174310&um=1&ie=UTF-8&hl=en&sa=N&tab=wl Why should the island stay invasive species free? Do you agree?

42. Exam Question (a) Discuss the impacts of a named alien species introduced as a biological control measure. ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ (3) (Total 5 marks)

43. (a) • named alien species e.g. western mosquitofish / small Indian mongoose /rosy wolfsnail; cane toad • introduced for removal of crop pests; • competes with native species; • no natural predators • excessive predation on native species that do not have defences; • impacts industry such as tourism/harvesting of natural resources;Accept other specific examples of effects. • 3 max