EBIO 1220 Lecture Notes - Lecture 34: Keystone Species, American Chestnut, Pisaster

• School: CU-Boulder
• Department: Ecology & Evolutionary Biology
• Course: EBIO 1220
• Professor: Melbourne

Document Summary

Co(cid:373)petiti(cid:448)e e(cid:454)(cid:272)lusio(cid:374) if (cid:1006) spe(cid:272)ies ha(cid:448)e the sa(cid:373)e (cid:374)i(cid:272)he the(cid:455) (cid:272)a(cid:374)"t li(cid:448)e i(cid:374) the sa(cid:373)e pla(cid:272)e. Oda (cid:271)ottles leaf litter a(cid:374)d lid. Number of trophic links between species (food chain length) Support the energetic hypothesis because the container with more lead litter (high rate of litter fall) had more trophic links. Co(cid:374)(cid:272)lusio(cid:374) redu(cid:272)i(cid:374)g e(cid:374)erg(cid:455) i(cid:374)put redu(cid:272)es food (cid:272)hai(cid:374) le(cid:374)gth. Containers with most leaf litter had most trophic links. More energy into the bottom of the food chain (energetic hypothesis), food chain will be longer. Trophi(cid:272) cas(cid:272)ade e(cid:454)a(cid:373)ple of ho(cid:449) feedi(cid:374)g relatio(cid:374)ships stru(cid:272)ture (cid:272)o(cid:373)(cid:373)u(cid:374)ities. Ho(cid:449)s us that earl(cid:455) o(cid:374) i(cid:374) the (cid:1005)97(cid:1004)"s this food (cid:272)hai(cid:374) did (cid:374)ot i(cid:374)(cid:272)lude or(cid:272)as (cid:894)it stopped at otters(cid:895) tio so there were large numbers of otters and small numbers of sea urchins. Whe(cid:374) or(cid:272)as (cid:449)ere added to the food (cid:272)hai(cid:374) otters de(cid:272)li(cid:374)ed a(cid:374)d ur(cid:272)hi(cid:374)s i(cid:374)(cid:272)reased. This is because there were less otters due to orcas eating them so therefore less urchins were being eaten.