Final Exam Review for 2500
1. Plant Succession
Primary Succession: When plants get established on land that was not previously
vegetated and there is a new substrate
Environmental conditions: newly formed substrate
examples: deltaic deposits, volcanic ejecta
Secondary Succession: invasion of land that had pre-existing vegetation
ie fire burning, cultivation. Mention high park example
Environmental conditions; Replacing existing. Developed biol legacy
2. 4 basic components of soils: mineral matter(45%), organic matter(5%), air(25%),
3. Chemical weathering involves destroying primary minerals and creating secondary ones.
It is the chemical breakdown or decomposition of rock minerals involving chemical
Qtz-SiO2, it is resistant to weathering because of the Si4+ tetrahedral tightly bonded to
O2 atoms. The net positive charge of Si is bonded to 0 8-, leaving Si with a -4 charge.
Strong chemical structure!!
Three other minerals are mica, augite, and feldspar.
Mica is more resistant to weathering because it has alternating tetrahedral sheets of
silicon and aluminum. Other atoms easily replace silicon, there is no tetrahedral pyramid
and they aren’t packed closely togerher.
There are six types of chemical weathering. DCHHO.
Dissolution-CaSO4+4H2O-> Ca+So4+H2O. dissolves into ions
Carbonation-carbon dioxide and water combine to form carbonic acid. This breaks
apart to H and HCO3 and reacts with minerals.
Secondary clay minerals are insoluble products of weathering. They are highly insoluble
ad divided into silicate clays and ALO clays. Silicate clays are colloids, whereas ALOs are
the end products of long weathering sequences.
4. Cation exchange capacity refers to
5. The three types of organic matter in soils are living organisms (the soil biomass),
carbonaceous remains of organisms which once occupied the soil (freshly decomposed),