Population Growth Flashcards
(31 cards)
Reindeer on St. Paul Island
- Important food source
- population increased exponentially
- eventually population plummeted
What do you need to understand to predict a collapse?
- population growth
- density dependence
- resource exploitation
- stochastic events
birth rate
number of young born per female
fecundity
table of birthrates for females of different ages
Annual plants: what are they, which one did we study, and what type of population growth do they have?
- Annual plants live for one year
- we studied phlox drummondii
- They demonstrate geometric growth
Geometric rate of increase equation
future population / current population
R0 (net production rate)
- growth rate per generation
- in annual plants its the same as the rate of increase
- normally it is Ixmx
Exponential population growth
- overlapping generations
- unlimited environment
- constant rate
- usually when a population is coming to a new area for the first time
Exponential growth formula for current population
N0e^rt
r
intrinsic rate of increase
Net population growth (R)
r(change in t)N
change in population right now
rN
Scott’s pine
- growth seen in pollen accumulation in lakes
- after colonization, experienced exponential growth for 500 years
Whooping crane
-after federal protection, they experienced exponential growth
Elephants in Kruger park, south africa
- grew at exponential rate after hunting was banned
- not necessarily a good thing. Large mammals tend to reach a peak and then plummet when they grow like this
Collared dove
- had new habitat
- grew exponentially at first
- rate of growth started decreasing
- most likely bc of density dependence
Density independant growth
growth set by fixed parameters (R, r, or gamma)
density independent factors
fires, floods, tornados, etc…
Density dependent growth
assumes limiting factor in the environment
density dependent factors
food, water, nest sites, disease
logistic population growth
for populations that are density dependent
-S curve
K (carrying capacity)
the limit to the population that an environment can sustain
-birth and death rates at this number will even each other out
equation for current logistic growth
rN(K-N)/K
Demography
The study of all these statistics and how they change in a population over time
