A scientist is trying to determine the population size of western fence lizards (Sceloporus occidentalis) in the Sycamore Canyon Park in Riverside using the mark-recapture method. During her first sampling event, she caught and marked 50 lizards which she then released back into the population. A week later she caught a total of 45 lizards, 7 of which were marked. What is the estimated population size of the western fence lizard?

The mark-recapture method is an indirect method to estimate population sizes. In this example, the estimated population size of the western fence lizard is N = 321.42 individuals.

There are different methods to study population density.

There are direct methods and indirect methods.

Among these last ones, we might find the Mark-Recapture technique.

The Mark-Recapture technique assumptions are

The method consists of  

1) Capturing a first sample of individuals belonging to the population under study, in this case, lizard's population.

2) Marking the captured individuals and releasing them again.

3) Taking a second sample where a new capture is done

4) Counting the number of individuals that are already marked. These marked individuals belong to the first sample.

5) Calculating the population size by using the Lincoln Index or any other index.

The Lincolns Index estates that to estimate the total number of individuals in this population, N, the following equation must be considered:

                                    N =  (n1 x n2) / m

1) The initial sample has n1 number of individuals

2) The second sample has n2 number of individuals

4) The number of already marked individuals is m

5) The total number of individuals in the population is N

In the exposed example,

N =  (n1 x n2) / m

N = ( 50 x 45 ) / 7

N = 2250 / 7

N = 321.428 ≅ 321.42 individuals

The estimated population size of the western fence lizard is N = 321.42 individuals.

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approximately 321

Explanation:

Using the mark recapture method formula, we can estimate the population size of the western fence lizard from this.

N = (M*C)/R

Where N is the estimated pop size

M is the first capture marked

C is the total second capture

R is the marked recaptured

Thus, N = (50*45) / 7

N =2250/7 = approximately 321

the answers are a and c

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle