Some students estimated the population of daisies in a school field - AQA - GCSE Biology Combined Science - Question 5 - 2019 - Paper 2

To calculate the total population of daisy plants, we first need to find the area of the field. From Figure 3:

• Width = 62 m
• Length = 164 m

Total Area of the field: $ext{Area} = ext{Length} imes ext{Width} = 164 imes 62 = 10,168 ext{ m}^2$

Next, converting the quadrat size:

• Quadrant area = 50 cm × 50 cm = 0.5 m × 0.5 m = 0.25 m²

Calculating the number of quadrats that fit into the field: ext{Number of Quadrats} = rac{ ext{Total Area}}{ ext{Area of Quadrant}} = rac{10,168}{0.25} = 40,672

Finally, we multiply the mean number of daisy plants per quadrat by the total number of quadrats: Population of daisy plants = Mean per quadrat × Number of quadrats = 7.65 × 40,672 = 311,892.4

In standard form, this is approximately: $4.8 imes 10^5$

Several biotic and abiotic factors can contribute to the uneven distribution of daisy plants:

Biotic Factors:

• Competition: Other plants may compete for the same resources (light, nutrients, space), leading to fewer daisies in those areas.
• Predation: Animals such as rabbits or insects may eat the daisies preferentially in some areas, reducing their numbers.

Abiotic Factors:

• Soil Quality: Variations in soil fertility and composition can affect growth; areas with poor soil will have fewer daisies.
• Water Availability: Areas that retain water better will support more daisies than drier regions; inconsistent rainfall can lead to uneven growth.
• Sunlight: Variability in sunlight exposure due to shade from trees or buildings will influence daisy growth significantly. Areas receiving less sunlight will typically yield fewer daisies.