The effect of interspecific competition on population growth

1. The effect of interspecific competition on population growth • Moretz • Biology, 2016

2. Review • Ecological Relationships • Predator/Prey • Producer/Consumer • Symbiosis • Competition

3. Ecological Relationships http://images.sciencedaily.com/2012/02/120222154633_1_900x600.jpg https://denalibiomeproject.wikispaces.com/file/view/lynx-hare.jpg/73213523/lynx-hare.jpg

4. Ecological Relationships http://maggiesscienceconnection.weebly.com/uploads/5/1/0/5/5105330/639611123.jpg?218 http://a.static.trunity.net/files/199301_199400/199323/koaladiet2.jpg http://maggiesscienceconnection.weebly.com/uploads/5/1/0/5/5105330/441288099.jpg

5. Ecological Relationships http://learnaboutsymbiosis.weebly.com/uploads/2/8/8/4/28842393/6818205_orig.jpg https://c2.staticflickr.com/2/1375/4602378800_af525ec726_b.jpg http://media-2.web.britannica.com/eb-media/50/38250-004-EA9EA4DA.jpg

6. Niche & Competition • Niche • The role an organism plays in an ecosystem andthe resources it uses.

7. Competition • Struggle over scarce resources

8. Competition • Struggle over scarce resources • Intraspecific competition = within the same species

9. Competition • Struggle over scarce resources • Interspecific competition = between organisms of different species

10. Competition • Struggle over scarce resources • Food • Water • Shelter • Mates • Light

11. The Struggle for Existence • G.F. Gause, 1934 • Theory of Competitive Exclusion: describes what will happen to the populations of different species when they have nearly identical niches.

12. The Struggle for Existence • Predicted that when two species occupied the same niche, the population with the greater growth rate will be successful and the other will be eliminated. • No 2 species can occupy the same niche.

13. Experimental Evidence • Design and implement an experiment that supports or refutes Gause’s claim (paramecium focus).

14. Experimental Evidence • Design and implement an experiment that supports or refutes Gause’s claim (plant focus).

15. Background Info. • Paramecium • Unicellular • Eukaryote (nucleus) • Aquatic, freshwater • Use cilia to move • Consume algae, bacteria, decomposing plant material. • Eaten by other protists. • Reproduces asexually or sexually, 2-3 times per day.

16. Background Info. • Paramecium aurelia • Paramecium caudata

17. Sampling Technique (paramecium) • Culture: 4 mL of Paramecium in 128 mL of hay medium in 250 mL flask. • Sampling: • Agitate culture • Pipette 1 mL to sample culture. • Release 2-3 drops back into culture. • Quickly place next drop on slide and cover with cover slip. • Repeat 5 times. • Place remaining sample back into culture. • Count all organisms in each drop. • There are 20 drops per 1mL. One drop = .05mL. • Calculate the average number of organisms per 1 mL.

18. Background Info. • Raphanussativus • Poapratensis

19. Sampling Technique (plants) • Plant types: raddish and grass • Planter cups filled with soil to top rim. • Add a total of 20 seeds per plant • Ratios: • 100% grass • 80% grass, 20% raddish • 40% grass, 60% raddish • 60% grass, 40% raddish • 20% grass, 80% raddish • 100% raddish

20. Repeating Gause’s Competitive Exclusion Experiment • Design and implement an experiment that supports or refutes Gause’s claim. • Paramecium focus • Plant focus

21. Lab Timeline • Formulate a hypothesis regarding the effect of interspecific competition on population growth of Paramecium. (Tues.) • Draw a sketch of the experimental procedure. (Tues.) • Complete the experimental design diagram. (Tues.) • Create a data table. (Tues.) • Take initial observations of paramecium. (Wed.) • Establish paramecium cultures. (Wed.) • Collect data. (Oct. 5 – Oct. 20) • Analyze data. (Oct. 21)