To determine what would support the conclusion that the deer population is not changing size from year to year (net population change is 0), we need to consider both the birth and death rates, as well as any immigration or emigration of deer.
Given the data:
- Birth rate = 50 deer/year
- Death rate = 70 deer/year
This indicates that there is a net loss of 20 deer per year (70 deaths - 50 births = -20).
Now, let's evaluate the options provided:
A. About 20 deer per year immigrate to the tract of forest.
If 20 deer immigrate to the forest, that would offset the net loss of 20 deer per year from the births and deaths, resulting in a net population change of 0. This observation supports that the population is not changing in size.
B. About 20 deer per year emigrate from the tract of forest.
If 20 deer emigrate from the forest, that would increase the net loss (70 deaths - 50 births - 20 emigrants = -40), leading to a declining population. This does not support a population change of 0.
C. The average life span of a member of the deer population is 20 years.
Knowing the average lifespan does not directly relate to the net change in the population size over a year. It does provide context for understanding the population dynamics but does not address the immediate net change.
D. If a deer survives its first year of life, its average life span is 20 years.
Similar to option C, this information does not directly relate to the immediate net change in population size, as it does not take into account birth, death, immigration, or emigration.
Thus, the additional observation that supports the conclusion that the deer population is NOT changing in size is:
A. About 20 deer per year immigrate to the tract of forest.
2 answers