1. Chapter 6 Ecosystems and Communities Succession
Series of regular predictable changes in community structure over time
Result in climax community

2. Chapter 6 Primary Succession Terrestrial
Total lack of organisms and bare rock or water
Terrestrial
Pioneer Community
First to colonize bare rocks--lichens
Successional or Seral Stage
Multiple sequence of stages/communities
Climax Community
Relatively stable, long lasting, complex community
Entire sequence of stages called a sere.

3. Chapter 6 Characteristics of Climax Communities:
1. able to maintain mix of species for a long period of time
2. in energy balance
3. larger number and more kinds of organisms and interactions between organisms
è complexity and energy efficiency

4. Chapter 6 Secondary Succession
Succession in area after destruction or major disturbance, flood, fire, agriculture
More common and rapid than primary succession
Usually some soil, seeds or root mass that can re-establish
Adjacent area can be source of seed, etc

5. Chapter 6
Aquatic 
Except for oceans, most aquatic ecosystems are considered temporary. 
Ever increasing entrapment of soil particles and organic matter.
Less depth means establishment of submerged plants
 è terrestrial succession

6. Chapter 6 Types of Climax Communities Biomes
terrestrial climax communities with a wide geographic distribution.
Variation of species exist within biomes but exhibit similar pattern and processes
Same general structure of ecosystem
Same kinds of niches present

7. Chapter 6 2 primary factors which determine biome type: Precipitation:
total amount
form (rain, snow)
seasonal distribution—concentrated at particular time
Temperature:
temperature swings
length of seasons
Other factors: fires, winds, organisms 
Altitude and latitude can mimic these effects

8. Chapter 6 Desert: Lack of water is primary factor
Less than 25 centimeters (10 inches) precipitation per year. 
Lack of clouds means no insulation 
Can be quite cold/hot
Many types of plants and animals, most are quite adapted to conditions.
Large space between plants, dispersed animals too

9. Chapter 6 Grassland (aka: prairies or steppes):
Between 25 and 75 centimeters precipitation per year (10-30 inches).
Windy, hot summers: cold or mild winters. 
Fire is important in maintaining biome
Prevent invasion of trees
Cycles nutrients 
Large herds of grazing mammals, many insects, many birds.
Most converted to agriculture
0.004% of Texas Blackland Prairie remains

10. Chapter 6
Savanna: 
Similar in appearance to grassland, but has more trees.
Precipitation is between 50 and 150 centimeters per year ( inches), but it comes in a few heavy events, with drought in between.
Plants and animals behave accordingly.
Wildlife quite similar to grasslands.
Fire still important so trees fire resistant
Texas Post Oak Savanna

11. Chapter 6 Tropical Rain Forest: Near equator
Africa, C&S America, SE Asia, some islands
More than 200 centimeters precipitation per year (80 inches).
Some over 500 centimeters (200 inches).
Warm temperatures/relatively constant.
Many species.
Soils are poor since nutrients are stored in biomass of vegetation or washed out.
Highly weathered so clayey—sun and heat make?

12. Chapter 6 Temperate Deciduous Forest: Distinct summer/winter seasons.
Trees loose leaves in winter
100 centimeters (or more) of precipitation (40 inches).
Mild winters, 6 month growing season 
Relatively few species of trees.
Two or three major producers 
Many flowers, insects, birds and mammals.
Texas—Eastern and Western Crosstimbers

13. Chapter 6 Taiga (aka: Northern Coniferous Forest or Boreal Forest):
Short cool summer, long hard winter.
Up to 6 months, soil freezes
Precipitation between 25 and 100 centimeters per year (10 to 40 inches), with constant high humidity.
Trees see winters as dry due to precipitation in form of snow.
Needle shaped leaves.
Flexible branches

14. Chapter 6
Tundra:
No trees, permanently frozen soil (permafrost)—north of Coniferous forests
Low precipitation (less than 25 centimeters), but comes in summer when snow melts.
 Permafrost does not allow water to soak in....many small pools.
 Damage to systems takes long time to fix.
Same conditions on high mountains (alpine tundra) but different species

15. Chapter 6 Aquatic Ecosystems: Factors: Marine—high dissolved salts
- sun light penetrability
- nature of bottom substrate
- water temperature
- amount of dissolved material
Marine—high dissolved salts
Freshwater—low dissolved salts

16. Chapter 6 Marine systems Pelagic Ecosystems
Open ocean system, with free swimming organisms. 
Fish, whales, crustaceans,etc not attached to anything
phytoplankton (producer) in euphotic zone.
zooplankton
other consumers
nutrients are in short supply, except in few concentrated areas.

17. Chapter 6 Benthic Ecosystems Systems at bottom of ocean.
Critters attached or not
 If light can penetrate, plants exist.
 Substrate determines types of organisms which can occur.
 No light: abyssal zone.
 Warm waters è coral reefs
Mangrove swamps
Near shore region
Can lead to terrestrial ecosystem development

18. Chapter 6
Estuaries
Shallow partially enclosed area where freshwater enters marines systems.
Relatively few organisms capable of tolerating salt fluctuations seen in this system.
Large amount of nutrient inflow.
Typically, entire area has sunlight penetrating to bottom.
Many organisms use as nursery.
Trap sediment—salt marsh—terrestrial ecosystem

19. Chapter 6 Freshwater Systems Lakes and Ponds: Productivity:
littoral zone (has rooted plants)
limnetic zone (no rooted plants)
Productivity:
Temperature
Depth
Nutrients in water
oligotrophic lakes—longer life
eutrophic lakes—shorter life

20. Chapter 6
Dissolved oxygen (DO) determines what type of organisms will occur.
Free oxygen O2 
Biochemical oxygen demand (BOD)
A measure of how much decomposable organic matter is in the water.
 Enter through critter waste in lake, inflows of organic wastes, critter death, etc

21. Chapter 6 Streams and Rivers:
periphyton - organisms attached to rocks and bottom material.
Not much chance for plants, so most energy comes from material that falls in stream rather than from photosynthesis.
Many insects, fungi and bacteria use this organic matter.
Dissolved oxygen: less in slow, muddy rivers
Wetlands: transition areas