1. Chapter 50: An Introduction to Ecology & Biosphere
Scientific study of the interactions between organisms & their environment
**Environment= biotic & abiotic factors
Difficult to conduct experiments & control variables
Test hypothesis by manipulation of field populations & communities
Use of mathematical models
Manipulation of models to simulate long term effects

2. Subfields of ecology Organism ecology Population ecology
response of organism to abiotic factors
Physiological/morphological ecology
Evolutionary ecology
Behavioral ecology
Population ecology
examines factors influencing population size
Community ecology
studies interactions (predation, competition, disease, etc.) of all organisms in an area
Ecosystem ecology
focuses on energy flow & chemical cycling between abiotic factors & communities

3. Biotic factors influencing biomes Predation Parasitism Disease
Competition
Dependence on other species (ex. Pollinators)
Abiotic factors influencing biomes
Temperature
Varies regionally
Influences metabolism
Most organisms unable to regulate body temperature
Endothermic organisms function best at temp to which they are adapted
Water
Precipitation patterns vary regionally
Aquatic organisms contend with osmoregularity
Terrestrial organisms contend with desiccation
Sunlight
Latitudinal & seasonal variations affect organisms
Affects producer distribution which influences other organisms
Cues seasonal behavioral events

4. Fires, hurricanes, natural disasters Local/seasonal effects of climate
Wind
Global air circulation & wind patterns differ regionally
Effects evaporation, convection, transpiration, & morphology of organisms
Rocks & soil
Minerals, pH & physical structures affect distribution of plants & therefore animals
Fires, hurricanes, natural disasters
Periodic disturbances effect biological communities
Local/seasonal effects of climate
Bodies of water, mountains, seasons affect organisms
Examples- lake effect snow, lake turnover

5. Occupy the largest part of the biosphere
Aquatic biomes
Occupy the largest part of the biosphere
Marine biomes
[NaCl]=3%
75% of all biomes
Freshwater biomes
[NaCl]<1%
Vertical stratification
Thermocline- narrow separation between warm & cold H2O
Light penetration
Photic zone- sufficient light penetration for photosynthesis
Aphotic zone- no light penetration; no photosynthesis
Open H2O vs. bottom
Pelagic zone- open water
Benthic zone- bottom layer; bottom dwellers (benthos) feed off detritus (dead organic matter from upper zones)
Abyssal zone- deepest region (ocean only)

6. Depth of H2O & distance from shore
marine
Intertidal zone- covered by tide part of day
Neritic zone- shallow regions close to shore
Oceanic zone- far from shore
Freshwater
Littoral zone
shallow waters
close to shore
inhabited by algae, plant, mollusk, insect, crustaceans, fish, & amphibians
Limnetic zone
deep waters
do not support rooted plants
inhabited by variety of phytoplankton & cyanobacteria

7. Ponds- Small bodies of standing H2O
Freshwater biomes
Ponds- Small bodies of standing H2O
Lakes- Large bodies of standing H2O
Oligotrophic lake
Deep, clear, & nutrient poor
Mesotrophic lake
Eutrophic lake
Nutrient rich; support large, productive phytoplankton community
Streams & rivers- flowing habitats
Chemical & physical characteristics vary from source to mouth
Wetlands- areas covered with water & supporting hydrophytes (H2O plants)
Diverse biomes
Important for flood control & H2O filtration
Estuaries- area where fresh H2O river meets the ocean
Often borders wetlands & are called mudflats & saltmarshes
Salinity varies spatially & daily
Diverse communities
Breeding ground for marine invertebrates, fish, & waterfowl
Marine biomes
estuaries
Intertidal zone
Coral reefs- tropical H2O supports highly diverse & productive communities
Ocean zones

8. Geographic distribution based mainly on regional variations in climate
Terrestrial Biomes
Geographic distribution based mainly on regional variations in climate
Stratification
Forest biomes
Canopy
Low tree stratum
Shrub understory
Ground layer/forest floor litter
Root layer
Non-forest biomes
Herbaceous layer/shrub layer
Types of biomes
Tundra/permafrost
Taiga/coniferous forest
Temperate deciduous forest
Temperate grasslands
Chaparral
Deserts
Savannas
Tropical rainforest