The formula, r = (b – d) + (i – e), demonstrates that an increase in population size can be attributed to an increase in…

Question

BlackTom AI · Accepted Answer

The equation r = (b − d) + (i − e) shows how population size changes when births, deaths, immigration, and emigration occur.

Option a: home range. While the home range can influence how a population uses space and resources, it does not directly increase the numerical size of the population through the r calculation. It affects spatial dynamics more than the intrinsic rate of increase.

Option b: selection. Natural selection alters the genetic composition over time, not the immediate count of individuals contributing to population size in the current period. It is about allele frequencies, not the birth-death balance in this formula.

Option c: deaths. Since r includes a subtractive term (b − d), an increase in deaths would decrease r rather than increase population size. Higher d reduces population size in the short term.

Option d: competition. Competition can limit population growth by reducing survival or reproduction, potentially lowering b or increasing d, but on its own it does not directly cause an immediate increase in population size as the formula specifies. It tends to constrain growth rather than cause a rise.

Option e: emigration. Emigration reduces population size by moving individuals out, which increases the negative side of the (i − e) component. Therefore, higher emigration would decrease r, not increase it.

Option f: births. Births directly contribute to the (b − d) term; an increase in births raises b, thereby increasing r and the population size. This is exactly how r responds positively to more births.

Option g: resources (food). Availability of resources influences carrying capacity and growth potential, but the instantaneous change in population size is determined by births, deaths, immigration, and emigration. Resources indirectly affect those rates rather than cause a direct, immediate increase in r.

Option h: predators. Predation typically increases mortality or reduces reproduction, which would lower r rather than raise it, so this option would not explain an increase in population size.

BIO 181 (001&002) FALL 2025 FA25: Cumulative Exam 4 covers the most important content from Units 1-4: You can do this!!! : ) [Grade is out of 150/900 pts, the same am't of pts for the active learning "easy points" classwork.]

The formula, r = (b – d) + (i – e), demonstrates that an increase in population size can be attributed to an increase in…

View Explanation

Log in for full answers

Similar Questions

Every year you travel to the Kalahari Desert in Botswana to study meerkats (Suricata suricatta), a small carnivore belonging to the mongoose family. As you survey the various populations of meerkats and analyze the data, you realize that population growth is most influenced by the…

What were the ecological consequences of the rinderpest parasite for wildebeests and buffalo in the African Savannah? Choose 2 answers.

The figure above shows the growth and decline of the reindeer population on St. Paul Island. What is the main cause of the decline of the reindeer population?

Assuming that these populations are density dependent, what would be the likely outcome if the system depicted in the previous figure were allowed to continue?

You have been studying a very small population of Tasmanian Devils. What uncertainties about this small population should be of extreme importance and interest to you when prioritizing your research? (You may choose one or more answers.)

More Practical Tools for International Students

Homework AI Solver

Stylized Writing Assistant

Plagiarism Checker Assistant

Citation Assistant

In-Class Translation Assistant

Class Notes Assistant

Quiz Search Assistant

Past Exam Questions by School

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler