1. Population Ecology and the Distribution of Organisms
Lauryn Hepp, Sara Flash, Lorrin Johnson, and Tyra Christopherson
DON’T FORGET TO SAY CHAPTER 40!

2. Biological Hierarchy Biosphere = global ecosystem
Landscape = mosaic of connected ecosystems
Ecosystem = community of organisms in an area & the physical factors
Community = group of populations of different species in an area
Population = group of individuals of same species in an area
Organism
-Goes from least exclusive to most exclusive

3. 40.1 Climate influences terrestrial biomes
4 components of climate (abiotic)
Temperature
Precipitation
Sunlight
Wind
Factors affecting climate
Seasons
Bodies of water
Mountains

4. 40.1 Terrestrial Biomes
Biomes = major life zones characterized by vegetation type or physical environment
Ecotone = area of intergradation between biomes
Types of terrestrial biomes
Tropical forest
Savanna
Desert
Chaparral
Temperate grassland
Northern coniferous forest
Temperate broadleaf forest
Tundra

5. 40.2 Aquatic Biomes Zonation Types of aquatic biomes
Wetlands and estuaries
Lakes
Streams and rivers
Intertidal zones
Coral reefs
Oceanic pelagic zone
Marine benthic zone

6. 40.3 Distribution of Species
Dispersal = individuals’ movement away from area of origin or centers of high density
Transplants: Potential range vs. actual range
Biotic factors
Predators, food resources, parasites, etc.
Abiotic factors
Temperature
Water and oxygen
Salinity
Sunlight
Rocks and soil

7. 40.4 Population Density Density = number of individuals per unit area
Changes with births/immigration and
deaths/emigration

8. 40.4 Population Dispersion
Dispersion = pattern of spacing among individuals within a population
Clumped
Results from environmental conditions, mating behavior, or effective predation/defense
Most common
Uniform
Evenly spaced
Often a result of territoriality
Random
Unpredictable spacing
Occurs in absence of strong attractions/repulsions among individuals

9. 40.4 Population Dispersion

10. 40.4 Population Demographics
Life tables = age-specific summaries of survival pattern of a population
Survivorship curve = plot of the proportion of a cohort still alive at each age
Cohort = group of individuals of the same age
Type I
Large mammals w/ few offspring but provide good care
Type II
Some rodents, invertebrates, lizards, and annual plants
Type III
Organisms w/ large numbers of offspring but provide little/no care
Long-lived plants, fish, most marine invertebrates

11. 40.5 Models of Population Growth
r = b - m
b = annual per capita birth rate
m= Annual per capita death rate
r= indicates whether a population is growing or declining
r > 0 - Population is increasing, r < 0 - population is declining
Exponential Growth
Happens under ideal conditions (ex. Abundant food source)

12. 40.5 Models of Population Growth
Carrying Capacity
The max population size the environment can sustain (denoted by K)
Limiting factors
Energy
Shelter
Refuge from predators
Logistic Growth Model
Takes into account carrying capacity
Produces an S-shaped curve
Nutrient availability
Water
Suitable nesting sites

13. 40.6 Influences on Population Dynamics
Density independent vs. Density dependent
Density independent - A birth or death rate that does not change w/ population density. (similar to r - selection)
Drought
Density dependent - death rate that rises and birth rate that falls with rising density. (similar to K - selection)
Toxic Wastes
Disease
Predation
Competition for Resources
Territoriality
Intrinsic Factors

14. 40.6 Influences on Population Dynamics
Population Dynamics = population fluctuations
In addition to births and deaths, immigration and emigration are influences
Metapopulation - a group of populations linked by immigration and emigration