A group of individuals of the same species occupying a given
area Can be described by demographics Vital statistics such as
size, density, distribution, and age structure
Slide 3
Number of individuals in some specified area of habitat Crude
density information is more useful if combined with distribution
data clumped nearly uniform random Fig. 45-2a, p.802
Interval in which number of births is balanced by number of
deaths Assume no change as a result of migration Population size
remains stable
Slide 6
G = rN G is population growth per unit time r is net
reproduction per individual per unit time N is population size
Slide 7
Population size expands by ever increasing increments during
successive intervals The larger the population gets, the more
individuals there are to reproduce Fig. 45-5a, p.804
Slide 8
Maximum number of individuals that can be sustained in a
particular habitat Logistic growth occurs when population size is
limited by carrying capacity
Slide 9
As size of the population increases, rate of reproduction
decreases When the population reaches carrying capacity, population
growth ceases
Slide 10
Fig. 45-8, p. 807 initial carrying capacity new carrying
capacity Logistic Growth Graph
Slide 11
Population may temporarily increase above carrying capacity
Overshoot is usually followed by a crash; dramatic increase in
deaths Reindeer on St. Matthews Island Fig. 45-9, p.807
Slide 12
G = r max N (K-N/K) G = population growth per unit time r max =
maximum population growth rate per unit time N = number of
individuals K = carrying capacity
Slide 13
A populations growth depends on the resources of its
environment Deer introduced to Angel Island Population outstripped
resources
Slide 14
Any essential resource that is in short supply All limiting
factors acting on a population dictate sustainable population
size
Slide 15
Logistic growth equation deals with density- dependent controls
Limiting factors become more intense as population size increases
Disease, competition, parasites, toxic effects of waste
products
Slide 16
Factors unaffected by population density Natural disasters or
climate changes affect large and small populations alike
Slide 17
Patterns of timing of reproduction and survivorship Vary among
species Summarized in survivorship curves and life tables
Slide 18
Graph of age-specific survivorship Figure 45.11 Page 809
Slide 19
Fig. 45-11a, p.809
Slide 20
Fig. 45-11b, p.809
Slide 21
Fig. 45-11c, p.809
Slide 22
Over 6 billion people alive About 2 billion live in poverty
Most resources are consumed by the relatively few people in
developed countries
Slide 23
Expanded into new habitats Agriculture increased carrying
capacity; use of fossil fuels aided increase Hygiene and medicine
lessened effects of density-dependent controls
Slide 24
Exponential growth cannot continue forever Breakthroughs in
technology may further increase carrying capacity Eventually,
density-dependent factors will slow growth 39_18
Slide 25
Divide population into age categories Populations reproductive
base includes members of the reproductive and pre- reproductive age
categories
Slide 26
Show age distribution of a population Rapid Growth Slow Growth
Zero Growth Negative Growth
Slide 27
Fig. 45-17b, p.815
Slide 28
Direct counts are most accurate but seldom feasible Can sample
an area, then extrapolate Capture-recapture method is used for
mobile species
Slide 29
Capture, mark, and release individuals Return later and capture
second sample Count the number of marked individuals and use this
to estimate total population
Slide 30
Marking has no effect on mortality Marking has no effect on
likelihood to being captured There is no immigration or emigration
between sampling times
Slide 31
Maximum rate of increase per individual under ideal conditions
Varies between species In nature, biotic potential is rarely
reached
