Review- What effects do organisms do pioneer species have on an environment undergoing primary succession Explain- why do communities change over time Apply Concepts- When a whale or other large marine mammal dies and falls to the ocean floor, different waves of decomposers and scavengers feed off the carcass until nothing remains- do you think this is an example of succession- explain

Ch 4 Ecosystems and Communities 4.3 Succession

Krakatau exploded in 1883, leaving a tiny, barren island. 2 years later grasses were growing 14 years later there were 49 plant species, along with lizards, birds, bats, and insects 1929, a forest containing 300 plant species had grown How did the island ecosystem recover so quickly.

Ecological Succession Series of more-or-less predictable changes that occur in a community over time Some species move in and some die out Number of species typically increase.

Primary Succession Succession that begins with bare rock.

Primary Succession Pioneer Species First species to colonize barren areas Lichen—mutualistic symbiosis between a fungus and an alga- often the first life Fix atmospheric nitrogen, break down rock, and add organic material to form soil.

Secondary Succession Succession that begins with some surviving species and soil Occurs faster than primary succession Often follows natural or human disturbance.

Climax Communities Species in a stable, mature environment that won’t change into a different community.

Natural Disturbances Secondary succession in healthy ecosystems after natural disturbances often reproduces the original climax community.

Human-Caused Disturbances Ecosystems may or may not recover from extensive human disturbances.

Succession Lab Place a handful of dried plant material into a clean jar Fill the jar with boiled pond water and determine the initial pH of the water Cover the jar and place it in an area that receives indirect light Examine the jar every day for the next few days When the water in the jar appears cloudy, prepare microscope slides of water from various levels of the jar using a pipette to collect the water Look at the slides under the low powered objective lens and record your observations

Succession Analyze and Conclude Infer- Why did you use boiled water Infer- Where did the organisms you saw come from Draw Conclusions- Was ecological succession occurring- give evidence to support your answer Evaluate and Revise- Check you results against those of you classmates- Do they agree, how do you explain the differences