BIOL 1001 Chapter Notes - Chapter 8.5: Wallace Line, Californium, Ochrea
Document Summary
The role of history: dispersal is the movement of individuals from its place or origin to the location where in lives & breeds as adults. Exists b/c a deep trench in ocean maintained a water barrier to dispersal, even when the ocrea levels dropped during glaciations. Therefore, landforms on either side of line remained isolated, encouraging dispersal. In 1889, cheat grass was accidentally introduced to western north america. Cheat grass germinated so plants grow in early spring. Early growth compared to other plants allows cheatgreass to use more of the available water & nutrients. Within 30 years, cheat grass had take(cid:374) over (cid:1005)(cid:1004)(cid:1004)(cid:1004)"s of k(cid:373) of ha(cid:271)itat. If exotic species-not native- is introduced to new area, spreads rapidly, eliminates native species, it is said to be an invasive species. Invasive species: eliminates native species rapidly: species did not exist in certain parts of the work until recently, because they had neve dispersed.