Theory question 103
Population Ecology(a) Describe the process of succession in an abandoned farm land
(b) List seven ways by which micro-organisms can be controlled to maintain good health.
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(a) Secondary succession: bare/abandoned farm is first colonised by pioneer weeds and grasses (annuals) from seeds and roots left in the soil
These add humus and improve the soil; perennial grasses and herbs replace them
Shrubs then grow and shade out grasses; animals (insects, birds, rodents) move in and spread seeds
Trees establish and gradually replace shrubs
Finally a stable climax community (forest or savanna woodland, depending on climate) is reached
(b) Any seven: good personal hygiene/washing hands; proper sewage and refuse disposal; boiling or chlorinating drinking water; cooking food well and covering it; vaccination/immunisation; use of antibiotics and drugs; use of antiseptics and disinfectants; sterilisation (heat) of instruments; control of vectors (mosquitoes, flies); isolating infected people; pasteurisation of milk
Describe the stages in the order they happen, ending with the climax.