1. Abundance of starfish on a rock platform was studied by the quadrat method. The quadrat was a plastic frame with an area of 0.25 meter square. The rock platform was a rectangle approximately 20m x 30m. The numbers of starfish in 10 quadrat "drops" were: 8,0,14,11,3,1,0,0,7,2.
Estimate the starfish population on the rock platform.
2. A farmer wished to estimate the population abundance of a noxious weed species in a paddock measuring 300 x 400 meters. He used a rectangular wire quadrat frame 1.0 x 0.5 meter. The number of "target" weeds in 20 quadrat drops were: 2,8,0,15,11,0,2,1,0,9,16,3,7,13,0,1,7,0,8,2
What is the approximate population of weeds in the paddock?
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To estimate the population of starfish on the rock platform, we can use the quadrat method. Here's how to calculate the estimate:
1. Calculate the average number of starfish per quadrat drop: Sum up the numbers of starfish in the 10 quadrat drops and divide by 10.
(8 + 0 + 14 + 11 + 3 + 1 + 0 + 0 + 7 + 2) / 10 = 4.6
2. Calculate the area of the rock platform: Multiply the length and width of the rock platform.
20m x 30m = 600 square meters
3. Calculate the number of quadrats that can fit on the rock platform: Divide the area of the rock platform by the area of one quadrat.
600 square meters / 0.25 square meters = 2400
4. Estimate the starfish population: Multiply the average number of starfish per quadrat drop by the number of quadrats that can fit on the rock platform.
4.6 x 2400 = 11040
Therefore, the approximate starfish population on the rock platform is 11,040.
Now, let's move on to the second question about estimating the population of weeds in the paddock:
1. Calculate the average number of target weeds per quadrat drop: Sum up the numbers of target weeds in the 20 quadrat drops and divide by 20.
(2 + 8 + 0 + 15 + 11 + 0 + 2 + 1 + 0 + 9 + 16 + 3 + 7 + 13 + 0 + 1 + 7 + 0 + 8 + 2) / 20 = 4.05
2. Calculate the area of the paddock: Multiply the length and width of the paddock.
300m x 400m = 120,000 square meters
3. Calculate the number of quadrats that can fit in the paddock: Divide the area of the paddock by the area of one quadrat.
120,000 square meters / (1.0 meter x 0.5 meter) = 240,000
4. Estimate the weed population: Multiply the average number of target weeds per quadrat drop by the number of quadrats that can fit in the paddock.
4.05 x 240,000 = 972,000
Therefore, the approximate population of weeds in the paddock is 972,000.