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A pond starts the year with 250 water hyacinth plants…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A pond starts the year with water hyacinth plants. During the year, new plants form and plants die. Another plants float in from a stream, and plants are carried away.
- What is the population at the end of the year?
- What is the birth rate for each plant in the year?
- What is the death rate for each plant in the year?
Need a reminder? The key ideaShow
A population changes by . The birth rate is and the death rate is for each individual in a stated time. The density can also be given as a biomass or a percent cover.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. , , , , .
Plan. Use , then divide.
Step 1. (a) plants.
Step 2. (b) for each plant in a year.
Step 3. (c) for each plant in a year.
Answer: plants; ; .
Check. Births are more than deaths, and the population rose.
Watch out. The immigrants and emigrants are not in the birth rate and the death rate.
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