ENVIRONMENTAL SCIENCE : ECOSYSTEM 135
C. Life History
Niche specialization Broad Narrow
Organism size Small Big
Life Cycle Simple & short Complex, Long
D. Nutrient Cycling
Mineral cycles Open Closed
Nutrients exchange rate Rapid Slow
Role of detritus in nutrient regeneration
E. Selection
Growth For rapid growth āIā Mainly for feedback
selection control (k-selection
Quantity Quality
F. Overall Homeostasis
Internal symbiosis Undeveloped Developed
Nutrient conservation Poor Good
Stability (resistance to external perturbations Poor Good
Entropy High LowSUCCESSION: GENERAL PROCESS, CLIMAX
General Process
The process of succession being with a bare area or nudation formed by several reasons,
such as volcanic eruption, landslide, following sequential steps.
- Nudation
The process of succession begins with a bare area or nudation formed by several reasons,
such as volcanic eruption, Landslide, flooding, erosion, deposite, fire, disease, or other
catastrophic agency. Man also may be reason of formation of new lifeless bare areas for
example, walls, stone quarrying, burning, digging, flooding large land areas under reservoirs,
etc.
- Invasion
The invasion means the arrival of the reproductive bodies or propagules of various
organisms and their settlement in the new or bare area. Plants are the first invaders
(pioneers) in any area the animals depend on them for food. The invasion includes the
following three steps:
(a) Dispersal or migration: The seeds, spores or other propagules of the species
reach the bare area through air, water or animals.
(b) Ecesis: Ecesis is the successful establishment of migrated plant species into the
new area. It includes germination of seeds or propagules, growth of seedlings and
starting of reproduction by adult plants.