Biology 2483A Lecture : Estimating Abundances and Distributions

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orchidotter238

23 Dec 2011

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Sometimes we can only make due with relative population sizes; harder with absolute. Cougar tracks hard to see them so you cant tracks problem is it might be related to their activity (cold not very active). Mistake of a larger pop as opposed to activity. Area-based immobile or that can only move short distances. Counting everything within the known area and extrapolating it to a larger area. Area-based methods work well if individuals can be counted accurately within the quadrants and if the quadrants provide a good representation of the entire area covered by the population. To help ensure this, ecologists use as many quadrants as is feasible and they place them in randomly selected areas covered by the population. Area based can be used for mobile organisms by aerial view. Look left and right identify the distance you can see things. Function that explains the distance you can see things. Things that move around quadrants are difficult.

Related Questions

A population of 100 slugs randomly mates except for 18 selfbreeding individuals. The population has a gene for darkmottling colour, M, which produces dark individuals when ahomozygous MM condition exists, and green individuals when ahomozygous MâMâ condition exists. Heterozygotes are mottled. What is the proportion (genotypic frequency) of the dark, mottled,and green slugs in the succeeding generation of thispopulation? The initial allele frequency of M is 0.7 and ofM' is 0.3.

b) Not all populations experience equal amounts of geneticdrift or non-random mating. Evolutionary biologists use theeffective population size, N_e, to estimate the size ofan ideal population that would undergo the same amount ofgenetic drift or show effects of non-random mating as theactual population. Smaller populations have more drift. The value of N_e can be determined from:

N_e = 4 N_mN_f / N_m +N_f

Where N_m is the number of males in the actual population andN_f is the number of females.

If one population of elkhas 2 males and a harem of 6 females and another population in thesame

region has 1 male and 11females. Which population is more likely to experiencegenetic drift? Why?

(keywords to look up: Sewall Wright, effective population size, andFisherian ratio)

taupedog760

1. Which of the following risks is the result of random variation in the survival and production of offspring and is especially of concern for a small population?

A. Genetic drift

B. Environmental stochasticity

C. Inbreeding depression

D. Demographic stochasticity

2. Imagine you are a marine biologist and you want to estimate the population size of sea otters in your study area. Which of the following method would be the best approach to do this?

3. You captured and tagged 15 otters on Day 1. A month later, you resample the area and catch 30 otters, of which 3 are tagged. What is the estimated total population size?

4. If you used a mark-recapture approach to estimate the size of an animal population, but the tags were defective and fell off some of the originally sampled individuals, the method would tend to:

A. Underestimate the true population size

B. Overestimate the true population size

C. Either underestimate or overestimate the true population size, depending on how many individuals lost their tags

D. None of the above

5. Which of the following affect population size?

A. Birth, death

B. Birth, death, immigration, emigration

C. Birth, death, immigration, emigration, speciation

D. Birth, death, genetic drift

E. None of the above

The northern red backed vole (clethrionomys rutilus) is a mouselike animal that lives in the arctic. A random sampling surveyusing ten 1m? quadrats collected the following data on the numberof voles per quadrat:

2,0, 4,1,5,3,0,4,2,1

Assume that the entire sampling area contains suitable habitatfor the voles.

a) Using the data provided, estimate the population size ofvoles if the habitat has an ecological area of 230m?. Show yourwork.(3 marks)

b) WHat dispersion pattern best describes the distribution ofvoles sampled in this study?( 1 mark)

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Biology 2483A Lecture : Estimating Abundances and Distributions

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