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Flashcards in Part 2 Deck (21):

What are the four ways that population is measured?

1. Census
2. Sample
3. Relative Abundance
4. Mark-Recapture


What are the four primary population parameters?



How does the sampling method differ from the census method for measuring population?

The census method is a measure of the total number of individuals in a population, while the sample method is a measure of the number of individuals within a distinct area within a population.


Which formula relates the measurement taken from a population sample to the population as a whole? What do the variables represent?

N=C/aB where N is the estimated number of individuals within a population, C is the number of species counted in the sample, a is the proportion of the total area sampled, and B is the probability of correct detection.


The method of Mark-Recapture in determining population density which relates the ratio of the number of re-caught tagged individuals over the total number of individuals caught in a second sample to the ratio of previously tagged individuals in a first sample over the total population is known as?

The Lincoln-Peterson Method.


What are the major assumptions of the Mark-Recapture method?

1. Marks remain visible between captures.
2. Marked and unmarked animals are equally likely to be caught.
3. No immigration or emigration
4. The catch-able population has been identified.


Define semelparous

Reproduces once in a life-time


Define Iteroparous

Reproduces multiple times in a life-time


What is demography and what are its primary and secondary goals?

Demography is the statistical study of populations and their age structures as well as density and vital statistics (birth and death rates). The primary goal of demography is to project population growth, and its secondary goal is to determine sensitive and important ages.


What is a cohort and how does it relate to life-tables?

A cohort is a group of individuals all born roughly at the same time. A life table measures the mortality rates of a cohort as it relates to their age groups.


How is survivorship (Ix) calculated?

By dividing the number of individuals currently alive in an age group by the number of individuals that were alive at the beginning of their cohort.


How is mortality for an age group calculated?

By dividing the total number of fatalities between the measured age group and the next age group after by the total number of individuals originally within the age group. (a_x-a_(x+1))/a_x)


What is the measurement m_x?

The fertility schedule for a cohort i.e. the number of females produced per female in age class x.


How is the net reproductive rate R_0 calculated?

It is the number of daughters produced in generation t+1 divided by the number of daughters produced in generation t. Or the sum of all l_x*m_x for a cohort.


Define the mean length of a generation.

The average time between the birth of a female to the birth of her average offspring.


Calculate population size after six time steps using the following data:

K = 1600
r = 0.07

N_0 = 1333

Nt = K / {1+([K-N0]/N0)e-rt}

N6 = 1600 / 1+([1600-1333]/1333)e-0.07*6

N6 = 1414


Define Gause's competitive exclusion principle.

Two species with the same primary limiting resource cannot coexist in the same place at the same time.


What are the growth rate equations for two species 1 & 2 in the Lotka-Volterra model?

dN1/dt = r1N1 [(K1-N1-aN2)/K1]
dN2/dt = r2N2 [(K2-N2-βN1)/K2]


What are the 5 basic assumptions of the LV predation model?

a. encounters are assumed to occur at random in a homogeneous environment.
b. predators are specialists.
c. predator and prey populations are closed.
d. no self-limitation in the prey population.
e. predators have a type-1 functional response.


Define functional response.

the change in the per capita killing rate with changes in prey density.


What is the Allee effect?

Population growth is low at low individual numbers.