IGCSE Biology Extended 18.2 Adaptive features Topic Practice

CAIE IGCSE Biology Extended 18.2 Adaptive features question practice helps you revise this syllabus point with the course map in view. Use this page to focus on one topic, check the style of questions available, and connect each attempt back to the knowledge area it is testing.

EduNinja keeps Biology practice aligned to CAIE at Extended level, so you can move from topic review into exam-style question bank work without losing the syllabus structure. Start with a small set, mark the weak steps, then return to nearby topic links when a definition, graph, calculation, or explanation needs repair.

[Maximum number: 3]

The Hawaiian happy-face spider, Theridion grallator, is found on several of the Hawaiian islands. Some of the spiders have a very distinctive pattern on their bodies as shown in Fig. 1.3.

Fig. 1.3

Scientists think that the pattern on the bodies of the spiders is an adaptive feature. Explain the term adaptive feature with reference to this pattern.

(a)

Adaptive features are defined as the inherited features of an organism that increase its fitness. State what is meant by fitness in this context.

[ 1 ]

(b)

Rodents are the most common mammals in many hot deserts.

Fig. 2.1 shows the lesser Egyptian jerboa, Jaculus jaculus, which lives in North Africa and the Middle East in areas that have high daytime temperatures and very little rainfall.

Fig. 2.1

Like many desert-living mammals, jerboas are active at night.
Suggest two features of J. jaculus that adapt it to each of the following challenges of living in desert ecosystems:

[ 4 ]

(i)

very high daytime temperatures

1

2

[ 2 ]

(ii)

very little or no light at night

1
2

[ 2 ]

[Maximum number: 3]

Fig. 2.1 shows an Arctic wolf, Canis lupus. These wolves are one of the few mammals adapted to the extreme cold of the tundra in the Canadian Arctic and in Alaska.

Fig. 2.1

Arctic wolves show many adaptive features to a cold environment.

Explain what is meant by the term adaptive feature.

[Maximum number: 3]

Mangrove trees are hydrophytes because they grow in water.
Fig. 2.1 shows a young mangrove tree.

Fig. 2.1

(a)

An adaptive feature is a feature that increases the fitness of an organism.

[ 3 ]

(i)

Define the term fitness.

[ 1 ]

(ii)

Mangrove trees have many aerial roots and floating seeds.

Suggest how these adaptive features allow mangrove trees to survive in water. many aerial roots
floating seeds

[ 2 ]

[Maximum number: 7]

Fig. 2.1 is a photograph of some leaves of a water lily, which is a hydrophyte. The water lily has adaptive features that are found in many different hydrophytes.

Fig. 2.1

(a)

Describe what is meant by an adaptive feature.

[ 2 ]

(b)

A scientist calculated the mean number of stomata per $\mathrm{mm}^{2}$ in the upper and lower epidermis in tomato plants and water lily plants. Tomato plants are a type of terrestrial plant.

Table 2.1 shows the results.

Table 2.1

[ 5 ]

(i)

Compare and explain the differences in the mean number of stomata in a tomato plant and in a water lily plant.

[ 5 ]

[Maximum number: 1]

Which feature is a leaf adaptation for living in the desert?

large size

many stomata

rolled along its length

thin waxy cuticle

(a)

Fig. 3.3 is a photomicrograph of a cross-section of part of a xerophyte leaf.

Fig. 3.3

[ 2 ]

(i)

Describe one way the leaves of xerophytes are adapted to their environment.

[ 1 ]

(ii)

Describe one way the roots of xerophytes are adapted to their environment.

[ 1 ]

[Maximum number: 1]

Samphire is a plant that grows in coastal areas. It has adaptations that enable it to live in areas with high salt concentration in the soil and strong winds.

Which adaptations would samphire possess to minimise water loss from root cells by osmosis and leaves by evaporation?

salt concentration

in root cells

leaf surface area

high

low

high

low

[Maximum number: 2]

Cheetahs, Acinonyx jubatus, are carnivores found in the dry grasslands and woodlands of southern Africa. Cheetahs hunt for food during the day. They eat deer and antelope.

The cheetah is the fastest mammal on land but can only run at high speed (sprint) over a short distance. Its hunting strategy is to creep up on prey and then sprint to catch them.

Fig. 3.1 is a photograph of a cheetah in its natural habitat.

Fig. 3.1

Suggest how these adaptive features enable cheetahs to survive in their natural environment. fur colouring
streamlined body shape

[Maximum number: 1]

Researchers investigated the effect of adding cattle manure (cattle faeces) to fields where snap bean plants, Phaseolus vulgaris, were grown. Cattle manure contains some protein.

Snap bean plants are legumes which have root nodules that contain nitrogen-fixing bacteria.

Fig. 4.1 shows some root nodules.

Fig. 4.1

Suggest the advantage to farmers of having snap bean plants that have a large number of root nodules.

0 selected

Question 1(b)(ii)

Question 2

Question 2(a)

Question 2(b)

Question 2(b)(i)

Question 2(b)(ii)

Question 2(a)(ii)

Question 2

Question 2(a)

Question 2(a)(i)

Question 2(a)(ii)

Question 2

Question 2(a)

Question 2(c)

Question 2(c)(i)

Question 11

Question 3

Question 3(b)

Question 3(b)(iii)

Question 3(b)(iv)

Question 15

Question 3(a)

Question 4(b)(i)