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

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

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?

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

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

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

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)

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

Homework Part 1 of HW pkt