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Tổ chức Baccalaureate Quốc tế · IB Diploma · Biology · SL Chủ đề 22 3:56 Giọng đọc tiếng Anh · phụ đề tiếng Anh + 中文 được ghi trực tiếp
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A field edge looks richer in plants than its centre.
田边看起来比中心植物更丰富。
Choosing only the richest patches would build the desired result into the sampling method.
如果只选择最丰富的斑块，就会在采样方法中人为地构建出预期结果。
A population consists of organisms of one species in a defined area.
种群由特定区域内的单一物种生物组成。
Random quadrats estimate density without deliberately selecting patches.
随机样方在不刻意选择斑块的情况下估算密度。
A transect investigates change along an environmental gradient.
样线调查沿环境梯度的变化。
A quadrat is a defined area used for sampling.
样方是用于采样的特定区域。
A population is organisms of one species in a defined area.
种群是特定区域内单一物种的生物。
Estimate total abundance by multiplying mean density by area, with consistent units.
估算总丰度时，用平均密度乘以面积，注意单位一致。
This assumes sampled areas represent the habitat.
这假设所采样区域能代表栖息地。
Patchiness and too few samples widen uncertainty.
分布的斑块性和样本过少都会增加不确定性。
In the lab: Choose coordinates with random numbers before visiting the patches.
在实验室中，访问样地前使用随机数选择坐标。
Record quadrat area and counting rules.
记录样方面积和计数规则。
For a transect, use fixed distances and measure a relevant abiotic variable.
对于样线法，使用固定距离并测量相关的非生物变量。
Do not damage habitats or sample unsafe locations.
不要破坏栖息地或在不安全地点采样。
Known: five 0.25 square metre quadrats contain 3, 4, 6, 5 and 2 plants.
已知：五个0.25平方米的样方中分别含有3、4、6、5和2株植物。
Mean count equals 20 divided by 5, which is 4.
平均计数等于20除以5，即4。
Density equals 4 divided by 0.25, which is 16 plants per square metre.
密度等于4除以0.25，即每平方米16株。
Estimated abundance in 100 square metres equals 16 times 100, which is 1,600 plants.
在100平方米内的估计丰度等于16乘以100，即1,600株。
Your turn: Mean count is 6 in a 0.5 square metre quadrat.
请作答。 样方内平均计数为6，样方面积为0.5平方米。
Find density per square metre.
求每平方米的密度。
Pause the video and work it out.
请暂停视频，自己算一算。
Check: 6 divided by 0.5 is 12 per square metre.
核对：6 ÷ 0.5，每平方米 12 个。
Quadrats suit organisms that do not move quickly.
样方适用于移动缓慢的生物。
A food chain arrow shows the direction of energy transfer, not the direction a predator travels.
食物链中的箭头表示能量传递的方向，而非捕食者移动的方向。
Not true: Sampling only the most crowded patches gives an unbiased population estimate.
不正确：仅采样最密集的样方无法给出无偏的种群估计。
Choosing the most crowded patches overestimates density, because the samples are not representative of the whole area.
选择最密集的样方会高估密度，因为这些样本不能代表整个区域。
Unbiased estimation needs random or systematic sampling decided before looking at the plants.
无偏估计需要在观察植物之前确定采用随机或系统抽样。
A population consists of organisms of one species in a defined area.
种群是指在特定区域内某一物种的生物体集合。
Estimate total abundance by multiplying mean density by area, with consistent units.
通过平均密度乘以面积来估算总丰度，注意单位需一致。
Watch for quadrats suit organisms that do not move quickly.
请注意：样方适用于移动缓慢的生物。
The mean count is 5 in a 0.20 square metre quadrat.
在0.20平方米的样方中，平均计数为5。
Find the density per square metre.
求每平方米的密度。
Sampling only crowded patches overestimates the population.
仅对密集斑块进行采样会高估种群数量。
The result is a density of 25 per square metre.
结果是密度为每平方米25个。
The quadrat positions were chosen from coordinates before anyone looked at the plants.
样方位置在观察植物之前就按坐标选定。
That removes the bias of choosing interesting patches.
这样可以避免挑选有趣区域带来的偏差。
Two fictional sites have mean quadrat counts of 6 and 9, but quadrat areas of 0.25 and 0.50 square metres.
两个虚构样地的平均样方计数分别为6和9，但面积分别为0.25和0.50平方米。
Compare density; propose a defensible sampling design.
请比较密度，并提出一个合理的抽样设计。
The densities are 24 and 18 plants per square metre.
两地的密度分别是每平方米 24 株和 18 株。
The larger raw count has the lower density.
原始计数较大的一方，密度反而较低。
Random or stratified random positions, equal sampling effort and repeats reduce location bias; record uncertainty before extrapolation.
随机或分层随机布点、相同的取样力度和重复取样可以减少位置偏差；在外推之前要先记录不确定度。
Pause and check yourself. Explain each point on screen in your own words, then change one number in the last example and say which assumption must still hold.
暂停一下，自我检查：用自己的话解释屏幕上的每个要点，再改动最后一个例子中的一个数字，说明哪个假设仍然必须成立。