CPSC 270 Lecture Notes - Lecture 4: Phenology, Pest Control, Agroecology
3 Oct 2018
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Document Summary
Ecology : study of relationships of organisms to each other & to their physical environment. Life cycle refers to much more than that. If there is a large population, it becomes a problem. R strategist : high birth rate, low survival, rapid reproduction in favorable situations, most insect (and weed) pests fall into this category. K strategist : low birth rate, high survival, more resources put into each offspring, population growth is slower, but more stable, very few insect pests in this category. Fecundity: rate at which eggs are produced. Fertility: rate at which new individuals are produced. Degree days: method of measuring temperature accumulation. Developmental minimum: minimum temperature needed for development to occur. Thermal constant: number of degree days that must be accumulated for an event to occur. Dd = (average daily temperature) - (developmental threshold) (max. temp - min temp)/2: regulation of insect populations: Perfectly density-dependent factor: never fails to control increase once a certain density is reached.
