Succession summary (A-level 2nd Year)

Succession: (to succeed = replacing them)



 Life on bare ground = bare rocks, concrete, water habitat.
 1st theory of ecology
 (links w topics = energy transfers in ecosystems, photosynthesis, factors affecting
photosynthesis, light intensity, sampling techniques)
 Def of succession = abiotic + biotic changes that happen in an ecosystem over time.
 Abiotic: Non-living parts of environment = wind, light intensity, soil depth, nutrition of soil
therefore they bring changes to biotic factors i.e. the organisms present.
 Biotic: organisms

Principles:

 Soil: Broken bits of rock. Organic matter (HUMUS) + mineral ions (plant nutrition)
 Woodlands: haven’t always been woodlands, could’ve once been grassland
 Organisms change an environment so then there’s changes of organisms so then they
change current habitat into something else



Primary Succession:



 Primary succession- area has no life (bare rock, new pond)



Where does Primary succession happen?
1) sand becomes sand dunes
2) lava of volcano is molten rock so when volcano erupts makes another layer of rock in its
3) immediate environment: no life until succession starts



How does primary succession happen?

1) No life, bare rock. First form of life colonising is called pioneer species (Lichens + Algae)
 Can break up rock.
 Withstand being dried out
 Withstand fluctuating temps
 Withstands low nutrient levels
 Can photosynthesise and nitrogen fix so they can produce proteins and DNA

2) Die and decompose to form HUMUS
 Forms thin soil layer on bare rock
 Change to abiotic and form soil (abiotic factor of environment)