2. http://www.epa.gov/region5/superfund/ecology/images/fishcartoon.gif http://www.uark.edu/depts/agripub/Publications/Agnews/mosquito.jpg http://www.mark-ju.net/wildlife/images/monkey03.jpg http://www.dimijianimages.com/Aggression-defense-page4/vultures.jpg Ecosystem Interactions & Factors that affect populations

3. What is a population? A group of members of the same species that live in the same area. The size of any population is constantly changing. WHY? Limiting factors - an environmental factor that prevents an increase in the number of organisms in a population or prevents them from moving into new habitats

4. Limiting Factors that affect populations in ecosystems: 2 types: 1) Abiotic - a) resources available - b) climate - c) natural and human disturbances 2) Biotic - a) competition among organisms - b) predation - c) cooperation and symbiosis - d) presence of disease

5. ABIOTIC: WHAT IS A RESOURCE? Anything needed by an organism for life Examples: _____________________________ Nutrients, water, sunlight/energy, space

6. ABIOTIC: What are examples of climate? temperature, humidity, atmospheric pressure, wind, rainfall These in turn can cause/contribute to some natural disturbances like: storms, droughts, fires

7. ABIOTIC: What are examples of human disturbances? logging development and construction

8. BIOTIC: What is competition? interaction between 2 or more organisms competing for the same resource in a given habitat Can occur between members of same species - Example: male mountain goats compete to determine who will mate and produce offspring Members of different species may compete for the same resources - Example: raccoons and ravens might both try and feed on eggs from the same nest of a common bird

9. BIOTIC: Competition For similar species to live together in the same area, they must have slightly different niches. WHAT CAN ORGANISMS COMPETE FOR? -All the abiotic factors! -Mates!

10. COMPETITION FOOD Organisms in an ecosystem have to compete with each other for available resources. http://www.harcourtschool.com/glossary/science/images/gr3/community3.jpg http://www.knology.net/~sgoswald/Eating.jpg

11. COMPETITION Organisms in an ecosystem have to compete with each other for available resources: http://www.dpiw.tas.gov.au/inter.nsf/Images/LBUN-5K538R/$File/fox_adultandcub.jpg http://www.gdccc.org/Records/EOY2004/NSEOY.htm shelter

12. COMPETITION Organisms in an ecosystem have to compete with each other for available resources: space/territory http://www.rilanationalpark.org/gr.phtml?dir=../../pictures/in_text&img=/65_1180.jpg http://www.elise.com/weblog/photos/prairie-dogs.jpg Prairie dogs - 5 to 35 per acre Mountain lion- 1 male per 50-300 sq. mi

13. COMPETITION Organisms in an ecosystem have to compete with each other for available resources: LIGHT http://vilenski.org/science/safari/cellstructure/chloroplasts.html http://www.csjbacau.ro/gallery/images/Beech%20Tree%20Forest%20in%20Slanic%20Moldova.jpg

14. COMPETITION Organisms in an ecosystem have to compete with each other for available resources mates http://www.wasatchcomputers.net/gallery/elk_fight.jpg http://www.biocrawler.com/w/images/thumb/3/34/200px-Peacock_courting_peahen.jpg

15. BIOTIC: What is predation? when one organism hunts and kills another organism for food Prey animals are well adapted to avoid being eaten. Some examples include: -Physical attributes: speed, mimicry -Physical defences: camouflage, quills (porcupine) -Chemical defences: odour (skunk), ink spray (octopus), etc… Mimic Octopus (2:59 min): http://www.youtube.com/watch?v=H8oQBYw6xxchttp://www.youtube.com/watch?v=H8oQBYw6xxc

16. PREDATION Organisms in an ecosystem that capture and eat other organisms to supply their energy needs http://personal.ecu.edu/wuenschk/rabbit-wolf.gif http://www.aphis.usda.gov/lpa/pubs/images/wspred_6.jpg

17. BIOTIC: What is cooperation? - between SAME kind of organisms - live together and help each other What is symbiosis? Between 2 DIFFERENT species live in/on or near a member of another species

18. COOPERATION Same species live together in groups EX: herds, packs, colonies, families, etc http://www.kenyatravelideas.com/african-elephants.html http://www.sphoto.com/medium/meercats37.jpg http://people.uleth.ca/~d.rendall/groom4.jpg Share food & childcare responsibilities Groom each other Take care of sick

19. COOPERATION Same species live together in groups EX: herds, packs, colonies, families, etc Hunt in packs Provide protection http://www.knology.net/~sgoswald/Eating.jpg http://rosswarner.com/zebras1.jpg

20. 3 KINDS of SYMBIOSIS 1)______________________ Both organisms benefit 2)______________________ One organism benefits; Other is neither harmed nor helped 3)_____________________ One organism benefits; Other is harmed in some way MUTUALISM COMMENSALISM PARASITISM Bed bugs (2:10 min): http://www.youtube.com/watch?v=WfKCcSPCOQohttp://www.youtube.com/watch?v=WfKCcSPCOQo

21. 1) MUTUALISM “Good for me - Good for you” Birds eat parasites living on the hides of giraffes and rhinos while enjoying protection from predators. Groomed animals lose their pests. http://www.imbt.org/science.htm http://www.hugheshome.net/jon/africa02/images/rhino_bird_JPG.jpg

22. 1) MUTUALISM “Good for me - Good for you” Insects transfer pollen between plants as they gather nectar for food. http://www.yksd.com/DistanceEdCourses/YKSDbiology/lessons/SecondQuarterLessons/Chapter5/5-5/images/3-way-mutualism.jpg http://www.providence.edu/bio/faculty/adams/LECTUREProvCollegeMutualism.html

23. MUTUALISM cont’d “Good for me - Good for you” Clown fish gets protection from enemies by hiding out in poisonous sea anemones http://www.zahnersatz.com/english/library/symbiosis.jpg Sea anemone gets scraps of leftover food dropped by fish

24. 2) COMMENSALISM “Good for me - Doesn’t bother you” http://www.geology.wmich.edu/gillespie/g322/Chapters/C16shark.gif Pilot fish receive scraps of food dropped by shark; Shark is neither harmed nor helped

25. COMMENSALISM cont’d “Good for me - Doesn’t bother you” http://www.abyssal.com/meeks/images/hermit_crab.jpg Hermit crabs make homes in shells abandoned by snails; Snail is not harmed by crab

26. 3) PARASITISM “Good for me - Hurts you” Barnacles are crustaceans that attach to the surface of whales and feed on their skin and fluids; Whale is harmed http://www.geology.wmich.edu/gillespie/g322/Chapters/C16parasitism.whale.gif

27. PARASITISM cont’d “Good for me - Hurts you” Tick feeds on dog’s blood; Dog has discomfort, can get diseases/infection from bite http://www.dogbreedinfo.com/guineafowltickphotos.htm

28. PARASITISM cont’d “Good for me - Hurts you” Tapeworms absorb food by living inside host intestine; host is harmed http://www.biology.ucok.edu/AnimalBiology/Platyhelminthes/tapeworms.jpg

29. INTERDEPENDENCE All living and non-living things in an ecosystem are interconnected and changing even one thing impacts the whole ecosystem. When one tugs at a single thing in nature, he finds it attached to the rest of the world. ~John Muir, naturalist, Sierra Club founder

30. Have you ever wondered why we don’t see millions of mice running around when we look out the window if they reproduce so quickly? The environment can only support a maximum number of individuals because of limited resources

31. Characteristics of a Population: As a population grows, each individual gets a smaller share of the resources in the area. If resources are scarce, some organisms will starve and populations will decrease. The organisms become stressed. Some die, others aren’t able to reproduce. This may lead to fewer births and more deaths. Eventually, the number of births = number of deaths The population is in EQUILIBRIUM

32. REMEMBER: EVERYTHING IS CONNECTED ! A decrease in the prey population means some predators will starve. Fewer predators mean prey population will increase. Increase in prey means more food for predators. Predator population will increase until there is not enough food... and the cycle repeats itself. Rabbit/Wolf simulation: http://www.shodor.org/interactivate/activities/RabbitsAndWolves/ http://www.shodor.org/interactivate/activities/RabbitsAndWolves/ BIOLOGY; MIller and Levine; Prentice Hall; 2006

33. Carrying Capacity Carrying Capacity is the maximum number of individuals an ecosystem can support without reducing its ability to support future generations of the same species The population overshoots the carrying capacity before it is reached If a population exceeds carrying capacity for a long time, it usually harms its environment.

34. For an ecosystem to be sustainable, none of the populations in the community can exceed its carrying capacity by very much or for very long. GOAL OF SUSTAINABILITY: meet the needs of the present generation without affecting the ability of future generations to meet their needs

35. Human Population Growth

36. Questions: 1) What does the following graph suggest about our population growth rate in the future? Discuss each line.

37. Questions: 2)Brainstorm reasons why the human populations seems to be growing exponentially, even after analyzing the previous graph. (You may use ideas from the Bill Nye video on Populations.)

38. Questions: 3) a. Finish sketching in the following curve based on the general graph showing a population reaching carrying capacity. b. If this were a graph of the Earth’s population, estimate the following: i) overshoot population ii) carrying capacity population