Question 19M.3.SL.TZ2.b
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.SL.TZ2.b |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Describe | Question number | b | Adapted from | N/A |
A survey was made of the intertidal zone at Butter Lump Bay, Great Cumbrae, Scotland. The three species of barnacle found were Elminius modestus (EM), Chthamalus montagui (CM) and Semibalanus balanoides (SB). The kite diagram shows the vertical distribution of these three species from the low tide mark at 0 m to 2.25 m above low tide.
[Source: reprinted from Estuarine Coastal and Shelf Science, 152, M C Gallagher, et al., The invasive barnacle species,
Austrominius modestus: Its status and competition with indigenous barnacles on the Isle of Cumbrae, Scotland,
pages 134–141, 2014 with permission from Elsevier]
Describe the distribution of C. montagui and S. balanoides barnacles in Butter Lump Bay.
[2]
a. both species present throughout the range ✔
b. C. montagui has small number of individuals «throughout»
OR
C.montagui occupies «mostly» upper shore/intertidal zone
c. S. balanoides «mostly» occupies low tide area ✔
OR
S.balanoides has large number of individuals «throughout» ✔
OWTTE referring to maximum numbers at specific heights.
Candidates were able to describe the distributions of the barnacles very well in part (b).
