Ecological Succession

Ecological succession is a [blank_start]series[blank_end] of predictable [blank_start]changes[blank_end] that occur in a community over [blank_start]time[blank_end].

Primary succession occurs in an area where there is no [blank_start]soil[blank_end] -- just bare [blank_start]rock[blank_end].

Primary succession occurs after a volcanic [blank_start]eruption[blank_end] where the lava [blank_start]cools[blank_end] and forms bare [blank_start]rock[blank_end]. It can also occur after a [blank_start]glacier[blank_end] melts.

Pioneer species are the [blank_start]first[blank_end] species to [blank_start]live[blank_end] in an area. They are [blank_start]producers[blank_end] that can tolerate [blank_start]poor[blank_end] growing conditions.

There are [blank_start]four[blank_end] stages in primary succession. Phase 1: Lichens ([blank_start]fungus[blank_end] + [blank_start]algae[blank_end]) grow on bare [blank_start]rock[blank_end]. They release an [blank_start]acid[blank_end] that begins to [blank_start]break[blank_end] down the bare rock.

Phase 2: The [blank_start]dead[blank_end] lichens mix in with [blank_start]broken[blank_end] down rock to create a [blank_start]rocky[blank_end] soil. [blank_start]Mosses[blank_end] then start to grow which helps create a more [blank_start]fertile[blank_end] soil.

Phase 3: [blank_start]Carcasses[blank_end] then begin to take root in the soil. [blank_start]Grasses[blank_end] start to grow. [blank_start]Herbivores[blank_end] begin to enter the ecosystem due to available food sources. The [blank_start]seeds[blank_end] from new species get brought in on the animal's [blank_start]fur[blank_end] or by the [blank_start]wind[blank_end].

Phase 4: Many new [blank_start]species[blank_end] have begun to grow in the area. There are now lots of [blank_start]biodiversity[blank_end] and [blank_start]food[blank_end] web begin to develop and the ecosystem continues to [blank_start]change[blank_end]. This is called the [blank_start]climax[blank_end] community.

There are also [blank_start]four[blank_end] phases in a Whale Fall Community. Phase 1: The [blank_start]dead[blank_end] whale starts to fall to the ocean floor.

Phase 2: The [blank_start]sharks[blank_end] and hagfish [blank_start]feed[blank_end] off of the carcass. Mollusks, sea stars, and crabs eat off the dropping on the floor.

Phase 3: The whale has now landed on the floor.Whale fall worms feed off of whale [blank_start]bones[blank_end]. Symbiotic bacteria digest the [blank_start]oil[blank_end] in whale bones. There interaction is known as [blank_start]mutualism[blank_end].

Phase 4: Invertebrates then [blank_start]feed[blank_end] on whale fall worms and each other until nothing is left.