Biology · Oct / Nov 2022 · Paper 42 · Question 5

all of the populations of different species in an ecosystem ;

natural selection ;

environment ;

these descriptions refer to the changes in 2013, but accept ora for 1969

A Meyer’s goshawk - range extends, downwards / to lower altitude ;

B Mackinlay’s cuckoo-dove - range extends, upwards / to higher altitude ;

C Island thrush - range does not extend downwards as much / AW ;

D Island leaf warbler - no / little, change in range ;

any three from:

1

decrease in population(s) (of island thrush) ;

2

ref to competition (between species at higher altitude) ; 3

ref to, increase in population(s) / extension of range of Mackinlay’s cuckoo-dove ;

4

idea that there is competition with other species for, breeding / nesting, sites (at higher altitudes) ;

5

habitat loss / deforestation / increased human

activity / tourism ;

6

disease ;

7

predation ;

8

loss of food source ;

9

climate change / global warming / enhanced greenhouse effect ;

10 (increased) hunting (at lower altitudes) ;

11 (increased) pollution (at lower altitudes) ;

12 introduction of, alien / new / exotic, species ;

13 AVP ;

any three from:

difficulty finding a mate ;

inbreeding ;

reduced fitness ;

decrease in genetic variation (within each population) / loss of alleles ;

increase in, genetic / inherited, diseases ;

more vulnerable to (pathogenic / infectious) disease (spreading) ; unable / less able, to adapt to change in environment ; at increased risk of extinction (as populations are so small) ; e.g. by natural catastrophes / introduced species / AW ; rarity linked to, egg stealing / poaching ;

AVP ;