1. Ecology Review

2. Chapter 52: Intro to Ecology Distribution

3. The Role of Abiotic Factors in the Formation of Land Biomes
Main defining abiotic factor is climate
Long-term; involving temperature, precipitation, sunlight, & wind
Macroclimate: patterns on the global, regional, or local level. Ex) winds, currents, mountains, water
Microclimates: small-scale environmental variations. Ex) under a log

4. Turnover in Aquatic Biomes
Turnover is the mixing of lake water as a result of changing temperature profiles
Occurs semiannually: fall and spring
Brings oxygenated water from the lake’s surface to the bottom and nutrient-rich water from the bottom to the surface.
Water is at its densest at 4°C!

5. Chapter 53: Population Ecology Population Characteristics
Population Density - # of individuals / unit of area
Counts
Sample size estimates
Indirect indicators – droppings, nests, etc.
Mark-recapture
Increases with births/immigration and decreases with deaths/emigration
Dispersion – pattern of spacing
Clumped
Uniform
Random
Demography – study of how populations change over time

6. Chapter 53: Population Ecology Growth Curves
Exponential growth – occurs under ideal conditions when resources are abundant
Logistic growth – population growth slows as carrying capacity is reached
Density-dependent limiting factors – factors that reduce birth rates or increase death rates as population density rises. Ex) competition, space, disease, predation
Density-independent limiting factors – factors that don’t affect the birth/death rate as density increases. Ex) natural disasters

7. Chapter 54: Community Ecology Interspecific Competition
Occurs between different groups of species
Can be +, -, or neutral (0)
Competition (-/-)
Predation (+/-)
Symbiosis
Mutualism (+/+)
Commensalism (+/0)
Parasitism (+/-)

8. Chapter 54: Community Ecology Keystone Species
Dominant species – most abundant
Keystone species – not necessarily abundant but have a pivotal ecological role or niche
Elimination of a keystone species could change the whole dynamic of the ecosystem

9. Chapter 54: Community Ecology Succession
Ecological succession - transition in species composition over ecological time
Primary - begins in lifeless area; no soil, perhaps volcanic activity or retreating glacier
Secondary - an existing community has been cleared by some disturbance that leaves the soil intact

10. Chapter 55: Ecosystems Energy Flow & Food Chains

11. Chapter 55: Ecosystems Food Webs

12. Chapter 55: Ecosystems Primary Productivity
Primary production – the amount of light energy converted into chemical energy by autotrophs
Provides and energy budget for the ecosystem – only what is made can be used
Gross Primary Productivity (GPP) – Total of all chemical energy made, but not all is available to consumers (plants need energy too)
Net Primary Production (NPP) = GPP – energy used for cellular respiration by producer (R)
NPP = GPP – R
In many ecosystems, NPP is about ½ of GPP!

13. Chapter 55: Ecosystems Energy Pyramids
10% Rule

14. Chapter 55 & 56: Ecosystems & Conservation Human Interference
Acid rain
Biological magnification
Greenhouse effect vs. global warming
Ozone layer destruction
Threats to biodiversity
Habitat loss
Invasive species
Overexploitation