Flashcards on Population Estimation Methods
Population Estimation Methods: A Student's Guide to Ecology
Tap to flip · Swipe to navigate
Population sampling methods
10 cards
Card 1
Question: What is a direct method of population sampling and what is it called when you count every individual?
Answer: A direct method counts every organism in a population; this is called a census.
Card 2
Question: When is the direct census method practical?
Answer: When organisms are large enough to see, the area is not too large (or can be surveyed from air), organisms are slow-moving, or they are stationary (e.
Card 3
Question: What are indirect methods of population sampling?
Answer: Methods that count only a sample of the population and use calculations to estimate total population size.
Card 4
Question: Name the two indirect population sampling methods described.
Answer: Quadrat method and mark–recapture method.
Card 5
Question: Write the formula used in the quadrat method to estimate total population size.
Answer: Total population size (N) = (number in sample × size of whole habitat) / size of quadrat.
Card 6
Question: List the key steps of using the quadrat method.
Answer: 1) Measure total area; 2) Choose appropriate quadrat size (same for all); 3) Place quadrats randomly across whole area; 4) Place several quadrats; 5)
Card 7
Question: Why must quadrats be placed randomly?
Answer: Because distribution of organisms may not be uniform; random sampling across the whole area gives a true reflection of distribution.
Card 8
Question: Write the mark–recapture formula shown.
Answer: P = (M × C) / R where P = estimated population size, M = total marked initially, C = total caught in second sample, R = number of marked in second sam
Card 9
Question: List the steps of the mark–recapture method.
Answer: 1) Define an area; 2) Capture and mark as many individuals as possible; 3) Release them; 4) Allow time to mix with unmarked; 5) Recapture many individ
Card 10
Question: What precautions are necessary for reliable mark–recapture results?
Answer: Short time between samples (to avoid births/deaths), repeat sampling to get an average, markings must not harm or alter behaviour/movement, marked ani