H2+Natality,+Mortality+and+Population+Growth

  __**Natality**__   > 
 * **Natality**: birth of new individuals
 * **Realized natality**: actual successful reproduction per female over time period – takes into account the seasonality of breeding, the number of broods, the length of gestation etc
 * **Age-specific birthrate:** number of offspring produced per unit time by females in specific age classes
 * __Mortality__**
 * **Mortality rate**: death rate – number individuals dying during a given time interval divided by average population size over that time interval
 * **Probability of dying**: number dying per individual present at the start of the time period
 * __Survivorship__**
 * **Survivorship**: The converse of mortality
 * Survivorship curve: survivorship data usually demonstrated this way
 * Three general Survivorship Patterns
 * Type 1= good survival of young with high death rates in old age (typical of large mammals, humans)
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">Senescence= deterioration with age
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">Type 2= steady mortality throughout the life (bird species)
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">Type 3= opposite of type 1 – high mortality early in life (typical of fish and plants, most species)

<span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">**__Life tables__** > > <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> __**The Fecundity Schedule**__: the number of eggs, seeds, or offspring in the first stage of the life cycle produced by an individual<span style="color: rgb(13, 12, 12)"> > <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"><span style="color: rgb(13, 12, 12)">**Fecundity**: birth rate (mean number of eggs produced per surviving individual) <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">__**Population Growth**__ A population increasing at its intrinsic rate will undergo a geometric increase in population number and follow the characteristic geometric curve <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> As population increases rapidly, the per capita rate (r) remains constant --> At each time interval, <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> > >
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> **Life tables**: summarize the fate of a group of individuals born at approximately the same time from birth to the end of the life cycle (pg. 79 has life table for a grasshopper)
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> **Cohort**: name for the group
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> **Cohort analysis**: investigation involving mortality rates, measured in life table
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> **Age specific survival rate**: proportion surviving to the start of the next stage
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">**Age specific mortality rate**: proportion dying at each stage
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">**Killing power**: the k value of a life stage
 * __K Factor Analysis__**
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">**K Factor Analysis**: technique that allows the identification of key factors contributing to mortality
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> This analysis highlights those stages suffering the greatest mortality which are responsible for fluctuations in loss rate and population size
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"><span style="color: rgb(13, 12, 12)">allows us to calculate of the basic reproductive rate [[image:basic_repro.jpg]]
 * Basic Reproductive Rate**: nu mber of offspring (eggs produced per individual)
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">offspring = number of eggs produced/number of individuals present at start
 * <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">this only happens if the population does NOT run out of resources
 * Geometric increase**: as much individuals are added to the population, more are increasing at that rate <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">
 * <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">the number individuals __added__ to a population = birth (B) and immigration (I)
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"><span style="font-family: Georgia,serif">the number individuals __removed__ from a population = death (D) and emigration (E)
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"><span style="font-family: Georgia,serif">growing population = B + I > D + E
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"><span style="font-family: Georgia,serif">changes in population size = [[image:pop_changes.gif]]

> <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">**Populations can be regulated by density:** their growth rate depends on the size of the population and how close it is to the maximum that the habitat can support
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">**Intrinsic natural rate of increase**: maximum potential for reproduction
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">[[image:intrinsic.jpg]]

<span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> __**Density-Dependent Growth**__: the logistic equation: unlimited growth of this kind = continuous population model > <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> > <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">
 * __Density-Independent Population Growth__**
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">**overlapping generations**: individuals of different ages are present in the population at one time
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">**rate of change of population size** (dN) at time (t) = intrinsic rate of increase (r) X population size (N)
 * [[image:rate_change.jpg]]
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> the growth of a simple population in a confined space – where resources are NOT unlimited = described by a graph that ALWAYS looks sigmoid (Greek S-shape)
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">[[image:sigmoid.gif]]
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> **carrying capacity (K)**: the upper limit is a constant for a particular set of conditions in a particular habitat
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">the population increases geometrically until an upper limit is approached
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> the population growth rate declines to zero as the population becomes MORE crowded and the population size stabilizes at the maximum that the environment can support – reaching an equilibrium population density
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> l**ogistic equation**: the sigmoid (s-curve) can be explained by multiplying the equation for density-independent growth by a density-dependent factor
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> rate of change of population size at time (t) = intrinsic rate of increase X population size X density dependent factor
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">[[image:density_dep_fact.jpg]]
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> when the population size (N) is small – the quantity N/K is also small
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)"> population increase = rN (geometric)
 * <span style="font-family: Georgia,serif; color: rgb(8, 8, 8)">N grows = dampening effect increases



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