Download Grade 12 Speciation Formative Question Paper

Grade 12 Speciation Formative [22 marks] Name ___________________
Date: ______
1.
2. 23M.1.HL.TZ2.33
The graphs show how the frequency (f) of a trait within a population changes when subjected to selection
pressures. Which graph shows stabilizing selection?
[1]
3. 22N.1.HL.TZ0.36
Two kinds of wolf spider rub specialized body parts together in order to produce distinct sounds to attract
females. Females of both groups will only allow a male of the same kind to mate with them. It has been
found through experimentation, however, that offspring can be produced from crossings between the two
groups. What can be hypothesized?
I. The groups are reproductively isolated.
II. They could be the same species.
III. This is an example of behavioural isolation.
A. I only
B. II only
C. I and II only
D. I, II and III
[1]
4.
5. 21N.1.SL.TZ0.21
Scientists studying ground finches (Geospiza fortis) on the island of Daphne Major in Galapagos found
great differences in the shapes of the beaks.
[Source: Public domain.]
What is the explanation for this variation in beak shape between the birds?
A. Ground finches grow larger beaks if there is competition for food.
B. They belong to different species.
C. They are adapted for different diets.
D. The more a beak is used by a ground finch, the larger it becomes.
[1]
6. 21M.1.SL.TZ1.25
On the islands of the St Kilda chain, off the coast of Scotland, there are small birds called St Kilda wrens
(Troglodytes troglodytes hirtensis). They look similar to wrens on the mainland of Scotland (Troglodytes
troglodytes indigenus), but they are larger and there are differences in the colour of their feathers.
What is the most likely explanation for these differences?
A. Convergent evolution
B. Stabilizing natural selection
C. Gradual divergence
D. Exposure to similar selection pressure [1]
7. 21M.1.HL.TZ2.36
Polyploidy has been a cause of rapid speciation in some plant genera, such as Helianthus. Which
observation is evidence that speciation has occurred?
A. A polyploid plant reproduces asexually.
B. A polyploid plant produces male and female gametes.
C. Fertile offspring are produced when a polyploid plant crosses with a diploid plant.
D. Fertilization can occur between polyploid individuals.
[1]
8. 22M.2.HL.TZ2.7
Explain how natural selection can lead to speciation.
[7]
9. 20N.2.HL.TZ0.8
More than 8 million different species are alive today but over the course of evolution, more than 4 billion
may have existed.
(a) Outline the criteria that should be used to assess whether a group of organisms is a species. [3]
(b) Describe polyploidy and how it can lead to speciation.
[5]
© International Baccalaureate Organization, 2024