Lincoln Index

What is the primary purpose of the Lincoln Index?

• To estimate the total population size of motile organisms.

• To calculate the biodiversity of an ecosystem.

• To measure abiotic factors in an environment.

• To determine the carrying capacity of a habitat.

Tags

NGSS.HS-LS2-1

Which of the following best describes how the Lincoln Index estimates population size?

• Multiply the number of individuals in the first sample by the total number in the second sample, then divide by the number of marked individuals recaptured.

• Add the number of individuals in the first and second samples, then subtract the number of marked individuals recaptured.

• Divide the number of marked individuals recaptured by the total number of individuals in the second sample.

• Subtract the number of marked individuals recaptured from the total population size.

What does 𝑛1 represent in the Lincoln Index formula?

• The number of marked individuals recaptured in the second sample.

• The total number of individuals caught in the first sample.

• The total number of individuals caught in the second sample.

• The total population size.

Which of the following is an assumption for the Lincoln Index to work?

• The population must be increasing due to births and immigration.

• Marked individuals must mix randomly within the population.

• The time between samples must be long enough for population changes.

• Marks must be visible only to researchers.

Using the Lincoln Index, estimate the population size if 100 marked individuals are released, and later 50 are recaptured out of 200 caught.

• 400

• 300

• 500

• 600

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DOK Level 2: Skill/Concept

How would you use the Lincoln Index to estimate the population of a species in a large forest area?

• Capture as many individuals as possible, mark them, and never release them back.

• Capture a sample of individuals, mark them, release them, and then recapture to estimate the total population.

• Only observe the animals from a distance to estimate the population.

• Use satellite images to count the number of individuals.

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DOK Level 3: Strategic Thinking

Using the Lincoln Index, estimate the population size if 200 individuals were initially captured, marked, and released. Later, 250 individuals were captured including 50 that were marked.

• 1000

• 900

• 800

• 1100

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DOK Level 2: Skill/Concept

If you catch and mark 20 fish in a pond during the first sample, and in the second sample you catch 25 fish, 5 of which are marked, what does this tell you about the population size?

• A. The population is very small, likely less than 50.

• B. The population is larger, likely around 100.

• C. The population is infinite because the marked fish were recaptured.

• D. It is impossible to estimate the population size without more samples.

Answer explanation

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Why is it important that marked and unmarked organisms do not differ in any significant way?

• To ensure that marked organisms are easier to recapture.

• To prevent bias in the population estimate.

• To allow marked organisms to leave the study area.

• To ensure marks do not wear off.

If 50 individuals were caught and marked in the first sample, 60 were caught in the second sample, and 15 of those were marked, what is the estimated population size?

• 200

• 150

• 300

• 250

Answer explanation