Question 19N.2.HL.TZ0.c
| Date | November 2019 | Marks available | [Maximum mark: 1] | Reference code | 19N.2.HL.TZ0.c |
| Level | HL | Paper | 2 | Time zone | TZ0 |
| Command term | Identify | Question number | c | Adapted from | N/A |
The black-legged tick (Ixodes scapularis) is an arthropod which sucks blood from humans and other mammals. It is encountered mainly in wooded and semi-wooded areas. Some ticks can be infected by the bacterium Borrelia burgdorferi. When a tick bites a human, the bacterium is often introduced, causing Lyme disease. Lyme disease is a public health problem in North America and, if left untreated, can cause important neurological impairment. The diagram represents the two-year life cycle of a tick.
[Source: Cary Institute of Ecosystem Studies / Leslie Tumblety]
Scientists fear that global warming will change the distribution range of ticks.
The graphs show the developmental stages of ticks throughout seasons in a densely human-populated area of south-eastern Canada, surrounded by woods (circled on the map). Values are already established for 2000 and are predicted for 2080.
[Source: reprinted from International Journal for Parasitology, 36(1), N.H. Ogden, A. Maarouf, I.K. Barker, M. Bigras-Poulin,
L.R. Lindsay, M.G. Morshed, C.J. O’Callaghan, F. Ramay, D. Waltner-Toews, D.F. Charron, Climate change
and the potential for range expansion of the Lyme disease vector Ixodes scapularis in Canada,
63–70, Copyright (2006), with permission from Elsevier]
Identify the month when small birds had the greatest chance of being infected by B. burgdorferi bacteria in the year 2000 and the month when they would be most likely to become infected according to the 2080 predictions.
2000:
2080:
[1]
«2000» August AND «2080» July ✔
Both required.
