Ant 15

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Ant 15
2012-02-15 00:06:24
Life History Theory

Ant 15 Midterm Review
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  1. Life History Theory
    This body of theory was developed to explain the diversity of life cycles among living things.

    • Two fundamental principles:
    • 1. natural selection
    • 2. trade offs

    • Attempts to identify the various trade offs an organism makes related to growth, survival, and reproduction
    • Goal is to understand variation in life cycle strategies

    Variation in characteristics reflect different allocation of an individual's resources. Available resources are finite.
  2. Trade-Offs
    • Energy is allocated in 3 seperate ways:
    • 1. Growth
    • 2. Maintenance & Repain
    • 3. Reproduction

    • Investment in current offspring- hinders growth and survival and reduces future reproduction.
    • Investment in self- increases fecundity and future reproductive potention, but age limited.
  3. RV Reproductive Value
    • current and future reproduction
    • -when young FR is high
    • -when old FR is low

    • Senescence
    • -shifts trade off to current reproduction
  4. r vs K selection
    • Explains selection pressures that determine reproduction strategy
    • Central trade off is:
    • # of offspring vs timing of reproduction.

    • r selected:
    • -suited to an unstable environment
    • -faster growth rate
    • -large number of offspring
    • -low parental care
    • Most are semelparous (single reproduction/mayflies)

    • K selected:
    • -suited to life in a stable environment
    • -slow growth rate
    • -small number of offspring
    • -higher parental care
    • Most are iteroparous (annual/multiple birthings)
  5. Life History Traits
    • -# of offspring
    • -juvenile development
    • -age sexual maturity
    • -age first reproduction
    • -parental investment
    • -senescence