1. When you finish… Pick up new note and homework packet
Work on notes (using slides from front table- bring back up when you finish)
Part 1 of HW pkt (succession) due Monday

2. Q: What are some influences on biological communities?
Limiting factors: any biotic or abiotic factor restricting population, reproduction, or distribution of organisms
Ex. ABIOTICS Sunlight, temp, water, fire, space, etc
Ex. BIOTIC
other species causing problem

3. Q: What are some influences on biological communities?
Range of Tolerance: upper and lower limit between which an organism survive
Ex. What is the range of tolerance for the steelhead trout in the picture below?

4. Q: Do ecosystems change?
Constantly!
Succession: changes in ecosystem as a result of various abiotic and biotic factors

5. Q: Do ecosystems change?
Primary Succession
Occurs where no soil is present (ie on lava flow or rocks)
Starts with growth of lichen on rocks (remember: relationship between fungi and algae), called pioneer species (first species present in area)
Pioneers die and decaying matter along with rock sediment develops into soil

6. Q: Do ecosystems change?
Small, weedy plants arrive then die to help add to soil
Process continues until it reaches a “stable point” with shade tolerant trees
Called a climax community
Probably unlikely to occur since abiotic factors (ie. Climate) are constantly changing, which means communities are constantly changing

8. Q: Do ecosystems change?
Secondary Succession
Occurs when a disturbance changes a community (ie. Fire, flood, windstorm)
New plants or animals might occupy the habitat after disturbance
Pioneer species are small plants (grasses, etc)

9. Q: Do ecosystems change?
Follows similar path to primary
Faster than primary
Soil already present
Some species still present
Sources of seeds and animals may be nearby

10. Homework
Part 1 of HW pkt