NATR 320 Lecture Notes - Lecture 9: Ruderal Species, Natural Selection, Inverse Relation
22 May 2020
School
Department
Course
Professor
Document Summary
Cannot be in the middle of the triangle. Adapted for low stress, high disturbance environment. Cannot tolerate competition or stress (cannot survive being shaded out) E. g. weeds live near humans (disturbance), dandelion (240 million seeds/acre), thistle (6 feet in one year, 1000 seeds per flowering head, survive 22 years in soil) Produce more seeds when conditions are right. Fast growth - can shade out other plants. Not adapted to stress or disturbing environments. Frequently use vegetable reproduction - sprout off another plant instead of production seeds. Life histories are driven by extrinsic and intrinsic factors. Extrinsic: factors operating from the outside that affect rates of age-specific reproduction and mortality (environmental influences) Intrinsic: tradeoffs among traits (phylogeny, physiology, development) Resources devoted to one body structure, physiological function, or behavior cannot be allotted to another. Natural selection favors the more optimal life history. Optimized life histories revolve conflicts between traits.
