Question 19M.3.HL.TZ2.b
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.HL.TZ2.b |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Outline | Question number | b | Adapted from | N/A |
The shore crab (Carcinus maenas) forages for food in the intertidal zone on rocky seashores. An experiment was carried out to assess predation at specified levels of food abundance. An area of shore was enclosed in a wire cage. All other food was removed from the encaged area except the mussels provided by the investigators. The number of mussels consumed was measured while the crabs foraged at densities of one, two or four crabs per cage.
[Source: reprinted from B D Griffen and D G Delaney, Ecology, 88 (12), pages 3012–3021,
copyright 2007, with permission, the Ecological Society of America]
Outline the role of natural selection in animal behaviour.
[2]
a. genetically based/innate behavior can be passed on to offspring ✔
b. behavior increases chances of survival and reproduction ✔
c. will increase in frequency/become more prevalent in a population ✔
Most candidates could only partly outline the role of natural selection in animal behaviour.
