Analyzing Human Impacts on Population Dynamics

Transcription

1 Analyzing Human Impacts n Dynamics Outdr Lab Activity - Bilgy Intrductin The ppulatins f varius rganisms in an ecsystem can be impacted bth directly and indirectly by human interactin. We will examine fur examples f human impact n ppulatin dynamics in this lab. These include accidental intrductin f disease and invasive species, changes in predatr-prey relatinship, and habitat lss. An ecsystem is hme t many species, and within an ecsystem there are varius fd chains. In this lab, yur grup will be acting as mice, wrking t gather fd fr yur muse ppulatin back at the nest. Yur ppulatin will experience varius changes that affect nt nly yur ppulatin f mice, but ther rganism ppulatins in yur area. Yu will each be given an area that will serve as yur ecsystem. Once yu have cllected fd and fed yur ppulatin, the hawks will feed n yur grwing ppulatin f mice. Fr yur ecsystem, this is hw rganisms are fed: 3 beans will feed 1 muse 4 mice will feed 1 hawk Pre-Lab Questins 1. Based n the intrductin given abve, develp a hypthesis that explains a way humans might impact a ppulatin f species. 2. Based n the rganisms described in the lab, identify the prducers, primary cnsumers, and secndary cnsumers. a. Prducer = b. Primary Cnsumer = c. Secndary Cnsumer = 3. Using yur answers frm questin 2 and the 10% rule, start with 1,000 J at the first trphic level and cnstruct an energy pyramid with the crrect energy quantities at each level.

2 Materials Each grup will need the fllwing: Plastic Cup String Meter sticks/rulers Tweezers (ptinal) Lentils/Split Peas White beans Stpwatch Calculatr Prcedure Scenari 1 Nrmal Cnditins Measure ut a 2 meter by 2 meter plt f grass n the lawn. Mark yur plt with the yarn prvided. This area is yur ecsystem! Spread yur beans thrughut yur plt f land. Three team members will be gathering beans using their hands fr 1 minute. Each muse can nly pick up 1 bean at a time. After 1 minute is up, cunt the ttal number f beans cllected and recrd this number in the data chart belw. 1 Grup # f Beans Cllected # f Mice muse) # f Hawks Ttal # f (cmmunity) Ttal Muse Ttal Hawk Using the number f beans recrded in the data table abve, calculate the number f mice, hawks, and ttal number f rganisms. When calculating, rund dwn t the nearest whle number (d nt wrry abut ppulatin density just yet, yu will calculate this later!) Sprinkle these beans back int yur ecsystem. This will happen each time yu are finished gathering fd, thereby representing reprductin f yur bean plants each year. Scenari 2 Disease Intrductin Oh, n! A grup f lcal hikers have recently returned frm a crss-cuntry trip and brught back sme unexpected hitchhikers n their bts a fungus that makes many f yur mice t sick t gather fd fr yur ppulatin. Therefre, nly ne muse is left t d all the cllecting. 1 persn in the grup will cllect beans fr anther full minute. After 1 minute is up, cunt the beans cllected and recrd this number in the data chart belw. Using this number f beans, calculate the number f mice, hawks, and ttal number f rganisms. Sprinkle these beans back int yur ecsystem. 2 Grup # f Beans Cllected # f Mice muse) # f Hawks Ttal # f (cmmunity) Ttal Muse Ttal Hawk

3 Scenari 3 Invasive Species Intrductin It seems that yur pr mice ppulatin cannt catch a break! A truck illegally dumps fill-dirt int yur field, cmpletely unaware that the dirt cntained a nn-native wrm species. This particular species begins t feed ff the rts f the white beans yur ppulatin f mice depends upn! Althugh yur sick mice have recvered frm the recent fungus utbreak, yur fd supply is cut shrt and yu can nly gather the green beans fr fd. All the grup members wh cllected fd in scenari 1 will cllect nly the green beans fr 1 minute. After 1 minute is up, cunt the beans cllected and recrd this number in the data chart belw. Using this number f beans, calculate the number f mice, hawks, and ttal number f rganisms. Sprinkle these beans back int yur ecsystem. 3 Grup # f Beans Cllected # f Mice muse) # f Hawks Ttal # f (cmmunity) Ttal Muse Ttal Hawk Scenari 4 Predatr Increase A strange grup f peple have shwn up and cut the grass in yur field - yu feel s expsed! Yu can n lnger hide frm predatrs in patches f tall grass when yu are ut cllecting fd. Cnsequently, the hawks in the area have taken ntice and are increasing in number. As a result f the changing ecsystem, yur equatins fr determining ppulatin numbers have changed. Since gathering fd is nw mre difficult, the mice need duble the energy/fd t survive. Because f less cver, the hawks, n the ther hand, require half the energy t hunt and therefre need less fd t survive. Dn t frget, thse pesky invasive wrms are still eating up yur white bean supply. Yu must cntinue t nly cllect the green beans. All the grup members wh cllected fd in scenari 1 will cllect nly green beans fr 1 minute. After 1 minute is up, cunt the beans cllected and recrd this number in the data chart belw. Using this number f beans, calculate the number f mice, hawks, and ttal number f rganisms. Sprinkle these beans back int yur ecsystem. Yur NEW fd ttals are as fllws: 6 beans will feed 1 muse 2 mice will feed 1 hawk 4 Grup # f Beans Cllected # f Mice muse) # f Hawks Ttal # f (cmmunity) Ttal Muse Ttal Hawk Scenari 5 Land Develpment Yur ppulatin f mice has figured ut why thse strange peple cut the grass back s far last year these crazy humans are building an apartment cmplex in yur field! As a result f this habitat lss, the area f yur ecsystem has been significantly decreased. Yur 2 meter by 2 meter plt f land is nw decreased t 1 m by 1 m. Again, remember that the wrm species is still present in yur ecsystem and s yu can still nly cllect green beans.

4 All the grup members wh cllected fd in scenari 1 will cllect nly green clred beans fr 1 minute. Make sure t have the yung muse keep time again! After 1 minute is up, cunt the beans cllected and recrd this number in the data chart belw. Cntinue t use the fd calculatins given in scenari 4. Pick up all remaining beans in yur plt, clean up the area, and return all supplies t yur teacher. 5 Grup # f Beans Cllected # f Mice muse) # f Hawks Ttal # f (cmmunity) Ttal Muse Ttal Hawk Data Analysis Once yu have finished cllecting beans acrss all 5 scenaris, calculate the area fr yur plt f land and use this number t determine the ppulatin density f hawks and mice fr yur ecsystem. AREA = length x width POPULATION DENSITY = / 4. Plt the ppulatin density numbers fr bth hawks and mice acrss each scenari in the graph prvided belw. Make sure t include title, axis labels (with prper scale), and units.

5 5. Pick tw scenaris and cmpare the ppulatin density data frm these tw scenaris t that f scenari 1 (nrmal cnditins).using the data frm yur graph, make inferences abut yur findings (trends, similarities, differences, etc.). 6. Based n the data, d yu accept r reject yur initial hypthesis? Justify yur answer. Drawing Cnclusins 7. Chse ne f the human impacts mentined abve and design a slutin fr reducing r mitigating thse impacts f human activities. Explain hw yur slutin will mitigate the impacts. 8. Explain tw pssible surces f errr in the lab prcedure and the impact f errr n yur data. (Meaning, what d yu think did NOT wrk r was pssibly cnfusing abut this lab and hw did it affect yur wrk?) Applicatin Apply What Yu Have Learned! Using the graph (n the next page), answer the fllwing questins: 9. Which species f mussel was present in this waterway in 1991? 10. What was the ppulatin density f uninids in 1998?

6 ZM density (per m 2 ) Uninid Mussel density (per m 2 ) 11. What was the ppulatin density f the zebra mussels in 1993? 12. Which f these species is the invasive species? Use data t supprt yur answer. 13. Explain tw different ways that the invasive species may bring abut the decline f the native species Changes in Mussel s Zebra Mussels Uninid Mussels Year Data taken frm: accessed 7/22/2014