Post on 18-Jan-2016
CHAPTER 52: POPULATION ECOLOGY
POPULATION DISPERSION PATTERNS
Exponential growth “J curve”
Population Growth Patterns Type of Growth?
Population Growth PatternsSome populations of organisms reach a plateau in their growth. This is called their carrying capacity. These populations are said to be growing with logistical growth.
“S curve”
carrying capacity
Carrying capacity – The number of organisms that can be supported by a particular ecosystem *within natural resource limits-without destroying it.
*Limiting Factors…
Population Growth Patterns1. What is the carrying capacity of the
population on the right?2. About how many days did it take for
the population to reach carrying capacity?
3. Which of the following is probably NOT a reason the population reached and maintained a plateau?a. limits in food supplyb. competition with other speciesc. competition for spaced. a major storm
Logistical vs. Exponential
Population Growth Patterns• What is the carrying capacity of the
population on the right? around 135 individuals
• About how many days did it take for the population to reach carrying capacity? about 80 days
• Which of the following is probably NOT a reason the population reached and maintained a plateau?a. limits in food supplyb. competition with other speciesc. competition for spaced. a major storm would probably not cause a population to maintain its size
Logistical vs. Exponential
...THE MATH…
N = Population SIze
dN = Change in Population Size
dt = Change in Time; generation
r = 1.0 = BR – DR (2-1 in this case)
1,500 = ?
*N small compared to K- Max rate of Increase
*N large/K limiting, Rate of increase is small (K-N/K is close to zero)
N = Population SIze
dN = Change in Population Size
dt = Change in Time; generation
r = 1.0 = BR – DR (2-1 in this case)
1,500 = ?
*N small compared to K- Max rate of Increase
*N large/K limiting, Rate of increase is small (K-N/K is close to zero)
POPULATION DYNAMICS
Birth rate/Death rateUnited States 14.1/8.7 Australia 12.7/7.3 Iraq 34.2/6.0 Japan 10.0/8.5
Italy 8.9/10.1 Russia 9.7/13.9
Other Factors?
Migration: Emigration,Immigration
Why?….for people… Life Expectancy,Health
Care,Sanitation Economics,Quality of
Life,Education
Density Dependent Factors: related to the density of the population. (disease, predation, competition)
Density Independent Factors: Not related to population size (killing frost, severe blizzard, hurricane, etc)
DENSITY DEPENDENTVSINDEPENDENT FACTORS
Three Patterns of Population
Growth
Causes?
CENSUS BUREAU
http://www.census.gov/population/international/data/ International Data China
Single Birth Policy When Instituted?
1978: SINGLE BIRTH POLICY: CHINA
In 1990?
R STRATEGISTS VS K STRATEGISTS
HW 52-9
Handout: Review of characteristics, curves
SURVIVORSHIP CURVES
SURVIVORSHIP CURVES
P/S:Compare how
matter and energy operate in ecosystems?
(Are they recycled)?
HW Ch54-2
Matter and Energy in an Ecosystem
ENERGY FLOW THROUGH ECOSYSTEMS
Text p1167
10% RULE
PYRAMID OF ENERGY:
Shows the energy available at each trophic level. The size of the blocks represents the proportion
of energy Measured in Joules or Calories
PYRAMID OF BIOMASS:
PYRAMID OF NUMBERS: Illustration of the number of organisms at each level
TROPHIC LEVELS
Usually 5 max Number of
energy steps from the sun
Tropho = nourishment
FOOD
KEYSTONE VS DOMINANT SPECIES
Definitions: ? HW Ch 53-10
P/S: Humans: keystone or dominant species? Dominant: Most abundant species in a community Keystone: Species that has greater influence on
community structure than you would predict based on #’s. Maintains species diversity (predation)
Grey Wolf Fig Tree ?
DDT1962
Persistence: Characteristics of certain chemicals that are extremely stable and may take many years to be broken down into simpler forms by a natural process.
Biological Accumulation: Buildup of a persistent toxic substance such as pesticides, in an organisms body.
Biological Magnification: The increase in concentration of a persistent toxin in the tissues of organisms at higher trophic levels. HW54-7