A survey gave the results shown in the given table for a species of the Red Sea anemone, Actinia tenebrosa , on a rocky shore in New Zealand, using a quadrat with an area of 0.25m 2 . Ouadrat 1 2 3 4 5 6 7 8 9 10 Number of red sea anemones 0 3 0 1 0 0 5 2 0 1 Calculate i) the species frequency and ii) the species density of A .tenebrosa from the results of this survey.

Species frequency is the measure of the chance of a particular species being found within any of the measured quadrats. The number of quadrats= 10, out of which the students found the sea anemone only in 5 quadrats. Then the species frequency will be = 5 10 × 100 =50% Species density is the measure of the number of individuals in a per-unit area. We know that, Species density = Total number of individuals/Total area of all quadrats. From the given table, we can calculate that the total no. of individuals = 12 The total area of all quadrats will be =100 × 0.25 =2.5 m 2 Thus, Species Density= 12 / 2.5 = 4.8 We can say that there could be 4-5 sea anemones per unit area.

A survey gave the results shown in the given table for a species of the Red Sea anemone, Isactinia tenebrosa , on a rocky shore in New Zealand, using a quadrat with an area of 0.25m 2 . Ouadrat 1 2 3 4 5 6 7 8 9 10 Number of red sea anemones 0 3 0 1 0 0 5 2 0 1 Suggest when it might be more appropriate to use species frequency rather than species density to record the abundance of a species.

Species frequency is the measure of the chance of a particular species being found within any of the measured quadrats. Species density is the measure of the number of individuals in a per-unit area. It is not always possible to count the number of species in a given area because many plants and animals grow on the surface overlapping each other or forming a covering on surface. In such cases, it becomes difficult to count the number of individuals. So we estimate the density of species or percentage cover of the species within a quadrat by finding the percentage of the area occupied by a particular species.

A survey was made of the Bengal dayflower Commelina benghalensis , growing on a lawn and in a field of young soybean plants. Ten 1.0 m2 quadrats were placed randomly in each area and the number of dayflower plants in each quadrat was counted. The results are shown in the given table: Ouadrat 1 2 3 4 5 6 7 8 9 10 Number of dayflowers on lawn 0 0 4 3 0 1 2 4 0 3 Number of daylfowers in field 0 0 0 2 5 0 0 1 0 0 Suggest two disadvantages with calculating percentage cover or using an abundance scale such as The Braun-Blanquet scale.

We calculate the species density or its frequency by using various sampling methods. If there are many individuals in an area or we are unable to count a large number because many plants and animals grow on the surface overlapping each other or forming a covering on the surface. In such cases, it becomes difficult to count the number of individuals. So we estimate the density of species or percentage cover of the species within a quadrat by finding the percentage of the area occupied by a particular species. Percentage cover can be calculated by using an abundance scale e.g. Braun-Blanquet scale. The percentage cover will not always add up all 100%. Because there can be bare ground in the quadrat or there can be plants overlying one another so the number will become more than 100%. Thus, we can say that it is not always advantageous to use these methods.

Suggest and explain the effect of the following on genetic diversity Artificial selection selective breeding habitat destruction and the release of farmed fish into the wild

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 18 - Classification Biodiversity and Conversation>Question>Q 8

Some students surveyed the species diversity of an area of woodland and some grassland nearby. The students used a 20-minute timed search. Explain why they used the same technique for the two areas.

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 18 - Classification Biodiversity and Conversation>Question>Q 8

Some students surveyed the species diversity of an area of woodland and some grassland nearby. The students used a 20-minute timed search. The students found 56 species in the woodland and 12 in the grassland. What other data could they have collected to compare the biodiversity of the two ecosystems?

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 18 - Classification Biodiversity and Conversation>Questions>Q 9

A survey gave the results shown in the given table for a species of the Red Sea anemone, Actinia tenebrosa, on a rocky shore in New Zealand, using a quadrat with an area of 0.25m².

Ouadrat	1	2	3	4	5	6	7	8	9	10
Number of red sea anemones	0	3	0	1	0	0	5	2	0	1

Calculate i) the species frequency and ii) the species density of A.tenebrosa from the results of this survey.

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 18 - Classification Biodiversity and Conversation>Questions>Q 9

A survey gave the results shown in the given table for a species of the Red Sea anemone, Isactinia tenebrosa, on a rocky shore in New Zealand, using a quadrat with an area of 0.25m².

Ouadrat	1	2	3	4	5	6	7	8	9	10
Number of red sea anemones	0	3	0	1	0	0	5	2	0	1

Suggest when it might be more appropriate to use species frequency rather than species density to record the abundance of a species.

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 18 - Classification Biodiversity and Conversation>Questions>Q 10

A survey was made of the Bengal dayflower Commelina benghalensis, growing on a lawn and in a field of young soybean plants. Ten 1.0 m² quadrats were placed randomly in each area and the number of dayflower plants in each quadrat was counted. The results are shown in the given table:

Ouadrat	1	2	3	4	5	6	7	8	9	10
Number od dayflowers on lawn	0	0	4	3	0	1	2	4	0	3
Number of dayflowers in field	0	0	0	2	5	0	0	1	0	0

Calculate the species frequency and species density of dayflower plants in each of the two areas.

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 18 - Classification Biodiversity and Conversation>Questions>Q 10

A survey was made of the Bengal dayflower Commelina benghalensis, growing on a lawn and in a field of young soybean plants. Ten 1.0 m2 quadrats were placed randomly in each area and the number of dayflower plants in each quadrat was counted. The results are shown in the given table: Calculate the species frequency and species density of dayflower plants in each of the two areas.

Ouadrat	1	2	3	4	5	6	7	8	9	10
Number of dayflowers on lawn	0	0	4	3	0	1	2	4	0	3
Number of daylfowers in field	0	0	0	2	5	0	0	1	0	0

Explain why it is important to use randomly placed quadrats for this survey?

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 18 - Classification Biodiversity and Conversation>Questions>Q 10

A survey was made of the Bengal dayflower Commelina benghalensis, growing on a lawn and in a field of young soybean plants. Ten 1.0 m2 quadrats were placed randomly in each area and the number of dayflower plants in each quadrat was counted. The results are shown in the given table:

Ouadrat	1	2	3	4	5	6	7	8	9	10
Number of dayflowers on lawn	0	0	4	3	0	1	2	4	0	3
Number of daylfowers in field	0	0	0	2	5	0	0	1	0	0

Suggest two disadvantages with calculating percentage cover or using an abundance scale such as The Braun-Blanquet scale.

HARD

AS and A Level

IMPORTANT

Biology for Cambridge International AS & A Level coursebook 2nd Edition Digital Access>Chapter 18 - Classification Biodiversity and Conversation>Question>Q 11

A sample was made of the animals on two rocky shores. Ten Quadrats were placed on each shore, and the number of animals of each species in each quadrat was counted.

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Calculate the D (Simpson’s Diversity Index) for Shore B by using the results given in the table.

Suggest and explain the effect of the following on genetic diversity: Artificial selection (selective breeding), habitat destruction and the release of farmed fish into the wild.

Important Questions on Classification Biodiversity and Conversation

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