ECCB 403 Exam 1
Population dynamics-
-change in the state of a population -measures the state of a population (abundance, density, biomass, incidence)
What does lambda=0.95 imply?
The population is expected to decrease by 5% per year on average
The first step to build a population matrix is
To draw lifecycle graph
When does a population exhibit geometric growth/decline (change)?
When the per-capita birth rate and per-capita death rate remain constant over time.
What do the results of sensitivity tell us?
what is the best way to improve the status of the population
What caused an increase in mortality of right whales?
-entanglement in fishing gear (gillnet and lobster pot) -ship strikes -pollution
What is sensitivity?
-how sensitive is lambda to changes in population parameters
what does a 95% confidence interval mean?
-if you were to repeat the analysis of the same subject the estimated value is expected to fall within the confidence intervals 95% of the time
Two potential explanations for the declined survival probability of right whales
-individuals are dying with a higher stage specific per-capita mortality rate -change in stage distribution
why is grouping individuals into a population important in conservation?
-it will affect the unit of management -it will affect the status of the populations
how does the natural log of density change when the population is exhibiting geometric growth?
-it will grow/decline linearly
finite per-capita population growth rate (population growth rate)-
-lambda -annual population growth rate if the time unit is 1 year -monthly population growth rate if the time unit is 1 month
What is reproductive value?
-measures a relative expected contribution of individuals in different stages to the future population abundance
describe what the sensitivity matrix will tell us
-measures how important vital rates are to the asymptotic population growth rate
What is the basic information about loggerhead seaturtles?
-more younger individuals in the population -reproductive value of older individuals is high -allocate more effort to protect juveniles -conservation is working in two ways: 1- increase the survival of eggs by hatching them artificially. 2- increase the survival of juveniles, subadults and adults by reducing fishery bycatch TED
What conditions under which natural log of population density grows/declines linearly with time?
-per capita rates are constant -exhibits exponential growth
if 1>lambda>0 then-
-population declines geometrically
if lambda = 1 then-
-population density remains the same
if lambda is greater than 1 then-
-population grows geometrically
describe parameters associated with lifecycle graph?
-solid arrows: proportion of individuals making the transition from one age class to another -dashed arrows: (reproduction) number of offspring per adult x offspring survival until age 1
When you start a Rstudio cloud project, you see "temporary copy". What are you supposed to do?
Click "save permanent copy"
What is the shape of a graph representing population abundance if the same proportion 0.3 of individuals (30%) dies and each individual in the population contributes to the birth of 0.2 individuals on average (one in five reproduce to one offspring) and these per-capita rates remain constant ?
Exponentially decreasing density
What is the stage of a graph representing population density if both per capita birth rate and per capita death rates are constant over time (but b>d)?
Exponentially increasing density
The asymptotic population growth rate and stable stage distribution are the properties of age-structured population, but they are not the properties of stage structured population.
False
The proportion of individuals dies over one year is 0.8. This value represents:
Per-capita death/mortality rate
Per-capita death rate-
The rate of death of individuals from time (t) to (t+1)
If all of the per-capita rates (birth, death and developmental rate) are constant over time, population density should change
exponentially with time
Vital rates-
per-capita survival/mortality rate per-capita birth/reproductive rate per-capita immigration rate per-capita emigration rate
Which of the following is a state variable
population density
which one of the statements is NOT true
there is no variable in statistical analysis
The average survival rate for a population can decline when a population abundance is increasing (assuming no immigration and emigration)
true
What is stable stage distribution?
- under asymptotic dynamics, distribution of individuals among stages remains constant
According to the figure (figure 1. on class 11 poll) which of the following is expected to make the population to start growing?
50% reduction in mortality of large juveniles
matrix-
- 3 rows and 3 columns - each parameter is an "element"
How to multiply a population matrix and population vector-
- first row x column= first row in product matrix - second row x column= second row in product matrix - third row x column= third row in product matrix
how to multiply and matrix?
- first row x first column= first element in matrix - second row x first column= second element in matrix - third row x first column= third element in matrix
component of a vector-
- number/density of individuals in that certain stage -the cumber of components is the same as the number of age classes in the model
Transient dynamics v. asymptotic dynamics (when vital rates are constant)
-TD: focus on short-term, deterministic responses to changes in the stage distribution of individuals -Asym.: when population grows/declines exponentially
Vector-
-a matrix with one column -each parameter is an "component"
scalar-
-a matrix with one row and one column
simpson's paradox
-a phenomenon in which a trend appears in several groups of data but disappears or reverses when the groups are combined -this is why a population growing in its abundance can have a reduced survival rate
State variables of a population
-abundance, density, biomass and incidence
why can a population growing in its abundance can have a reduced survival rate
-because stage distribution may be different -because the population may consist of more individuals in a stage with lower survival rate
Why are per-capita birth rates and per-capita death rates not the same for everyone in a population?
-depend on the current state of the age class and the density of each age class
Death rate/survival rate-
-the number of deaths in a population in a certain amount of time
State variables-
-variables representing the state of a population
when populations may not exhibit exponential change this is because
-vital rates are NOT constant
What are the three things you can calculate from constant population projection matrix?
1- asymptotic population growth rate 2- stable stage distribution 3- reproductive value
Four basic population dynamic processes-
1- population abundance 2- population density 3- biomass 4- incidence
North atlantic right whale population over time-
1500s- ~1000 1935- ~ 100 1980- ~300
Suppose the following script is run, what is displayed (value of n[3])? n < c(3,2,4,5,20,40) print (n[3])
4
Why does stage 2 have greater number of individuals than stage 1? (look at class 10 poll)
Because stage 2 includes multiple age classes
Why does stage 5 of loggerhead sea turtles have high relative reproductive value? (look at class 10 poll)
Because stage 5 have high survival rage, stages 1-3 have low survival rate and stage 5 has high fecundity
why do we need to structure a population based on age?
Because survival rate may be different among age classes and reproductive rate may be different among age classes
Leslie matrix v. Lefkovitch matrix
Leslie= age structure model. Age specific survival rates in subdiagonal elements of the matrix. The first row is for an age specific fertility terms Lefkovitch= population matrix associated with a stage-structured population
You administer medication to individuals and keep track of their symptoms/fate over time (a record for each individual is kept.) The data are
Longitudinal data
Case mortality rate (the mortality rate of people with symptoms) appears to be declining. It is still plausible that disease is becoming worse (according to Simpson's Paradox) beceause
More younger people (who previously did not develop symptoms before) are developing symptoms and they tend to recover.
When you learned a geometric/exponential growth, lambda was called
Population growth rate
Suppose we were to conduct many experiments. In each experiment we start with the same number of individuals in each stage and introduce two additional individuals (either 2 adults or 2 juveniles). On average, which while have the greater number of individuals in the future?
Populations with two additional adults and/or populations with two additional juveniles
Reproductive value v. Stable Stage distribution
RV= measures a relative expected contribution of individuals in different stages to the future population abundance SSD= under asymptotic dynamics, distribution of individuals among stages remains constant
Reproductive value v. fertility rate
RV= the future population abundance FR= during a certain time unit
What does reproductive value measure?
Relative contribution of individuals in a given stage to the future population abundance
To run a script, what do you click
Source
Describe the life history of loggerhead sea turtles-
Stage 1- eggs/hatchlings Stage 2- small juveniles Stage 3- large juveniles Stage 4- subadults Stage 5- Adults
The number of rows of leslie matrix and the number of component of an associated population vector must be the same
True
what are V and W?
V= reproductive value W= stable stage distribution (both column vector)
Population-
a group of individuals of one species that live in a particular geographic area
According to the sensitivity matrix, which parameter has the most impact on the asymptotic population growth rate?
a43 (look at matrix in poll 11)
Geometric/exponential growth results from
constant per-capita survival and per-capita birth rate
What are the ranges of lambda and how does population abundance/density change?
lambda>1 = population growing 1=lambda= population constant 1>lambda>0= population declines
Which is the correct way of multiplying a population matrix and population vector?
n(t+1) = An(t)
The first part of the figure caption (after figure X.) is usually
noun or phrase describing what was plotted without any interpretation
Per-capita birth rate-
number of offspring born and survive between time (t) and (t+1) PER individual parent at time (t)
fecundity
number of offspring produced per individual parent
Fertility
number of offspring that are born and survive one time unit (produced per parent)
Ecology
study of interactions among organisms and between organisms and physical environment
Birth rate-
the number of births in a population in a certain amount of time
The size of leslie matrix for a population is determined by
the oldest individuals in the population
immigration rate-
the rate of influx of new individuals INTO a population from other areas
emigration rate-
the rate of movement of individuals OUT of a population
