# Shared Flashcard Set

## Details

NEU Ecology Fall 2013 Lec set 6
Lec set 6 flashcards
30
Environmental Studies
11/06/2013

Term
 This is the number of organisms per unit area or volume
Definition
 Population density
Term
 Natality (the reproductive output of a population), mortality, immigration and emigration are all factors that can do what?
Definition
 Cause changes in population density
Term
 What are life tables in the grand scheme of demography?
Definition
 They describe the mortality schedule in a population and are an age-specific summary or the mortality rates operating on a cohort of individuals
Term
 The most frequently used part of the life tables is the (blank) column, the (blank)
Definition
 nx, number of survivors at age x
Term
 How are per capita rates of change measured in survivorship curves: on an absolute numerical curve or on a logarithmic scale?
Definition
 Logarithmic scale
Term
 Humans are an example of a type 1 survivorship curve. Provide the basic details behind this kind of survivorship curve
Definition
 Populations have low per capita mortality for most of their life span and then high losses of older organisms
Term
 Birds are prime examples of the type 2 survivorship curve model. Provide the basic details of this model
Definition
 A linear survivorship curve indicates a constant per capita rate of mortality that is independent of age
Term
 Fishes and marine invertebrates are prime examples of the type 3 survivorship curve. Provide the basic outline of this model type
Definition
 There is a high per capita rate of mortality early in life followed by much less and constant mortality thereafter
Term
 This is one form of life table and is common and easy to produce, focuses on a cross section of a population at a specific time and assumes that there are static/stationary populations
Definition
 This is a static life table
Term
 This is one type of life table and follows a cohort of organisms throughout their life, is difficult to make because birth and death rates can vary from year to year but is much more dynamic that its counterpart
Definition
 These are cohort life tables
Term
 This follows the overall survival of a large cohort born at the same time throughout its existance to directly generate cohort life tables
Definition
 Survivorship
Term
 What two factors are often used to generate life tables?
Definition
 The number of overall individuals that are alive over the course of time and mortality rates vs age in years
Term
 Fertility, the speed of individual development and longevity are all key factors that play into what?
Definition
 The intrinsic capacity for increase
Term
 What must we know in order to estimate changes in population size with respect to natality and death rates?
Definition
 We must know how natality and death rates change with age
Term
 What is the fertility schedule?
Definition
 It is the number of female offspring produced per female per unit time
Term
 What is the net productive rate, how is it calculated and what does its result mean?
Definition
 The net reproductive rate is the sum of the female offspring produced per female divided by the survivorship up to the critical age (in this case, reproduction capacity). R=1 means that the population is replacing itself exactly at a 1:1 ratio, R<1 means the population is shrinking and R>1 means the population is growing
Term
 What do we expect about mortality rates and female production rates for humans?
Definition
 We assume that these values remain constant and that there is no limit placed on population growth. Ex: if the whole population were over 50, it would not increase
Term
 Given the differences in mortality and female production with age, one would think that we need to specify the age distribution of the population but this was shown by Lotka to not be true. Why is this not true?
Definition
 Because a population with a constant schedule of natality and mortality rates will eventually approach a stable age distribution and maintain it indefinitely
Term
 What is the integral equation for the population size increase?
Definition
 Nt=N0ert where Nt = the number of individuals at time T, N0 = the number of individuals at time 0, r = the intrinsic capacity for increase in a given environment and t = unit time
Term
 What is the N(t)=N(0)e^rt equation called?
Definition
 It is the geometric growth pattern. On a logarithmic scale, the line is linear in shape
Term
 This is the mean period of time elapsing between the birth of parents and the birth of their offspring; also, how is this calculated?
Definition
 Mean generation length; this is taken as the sum of Ixbxx all divided by R0
Term
 In the N(t)=N(0)e^rt equation, how do you calculate r?
Definition
 r=loge(R0)/G
Term
 Do moisture content and temperature of an environment impact the intrinsic capacity for increase, r?
Definition
 Yes
Term
 Reduction in the age at first reproduction, an increase in the number of progeny in each reproductive event and an increase in the number of reproductive events will all serve what purpose?
Definition
 They will all increase the r value (intrinsic capacity for increase)
Term
 What is a good general rule to follow regarding the r value, or intrinsic capacity for increase?
Definition
 The earlier the peak in reproductive output, the larger the r value
Term
 Pacific salmon serve as a prime example of Big Bang reproduction. How does this method work?
Definition
 An organism reproduces once and then dies shortly thereafter
Term
 How does the process of repeated reproduction work?
Definition
 An organism reproduces several times throughout its life
Term
 What reproductive methods will be used when reproductive efforts are either high or low?
Definition
 In the case of high effort, big bang reproduction will take place. In the case of low effort, repeated reproduction will occur
Term
 Both lobelia telekii and lobelia keniensis are giant rosette plants that grow on Mount Kenya in Africe. Why does telekii prefer semelparity and why does keniensis prefer iteroparity?
Definition
 Telekii quickly dies off after its flowering event whereas keniensis can survive after flower events
Term
 How can reproduction actually hurt an individuals chance of survivorship?
Definition
 There's a possibility that an individual can actually put too much effort into reproduction (such as lactating) to the point where they may no longer be able to produce sufficient energy for themselves
Supporting users have an ad free experience!