現象的多様性,人口増加,変動する環境における情報
Edo Kussell1, Stanislas Leibler
1Laboratory of Living Matter and Center for Studies in Physics and Biology, Rockefeller University, 1230 York Avenue, Box 34, New York, NY 10021-6399, USA. kussele@rockefeller.edu
Science (New York, N.Y.)
|August 27, 2005
まとめ
生物は,センシングまたはストキャスティックスイッチを通じて環境の変化に適応します. ストキャスティック・スイッチングは,環境の変化が稀な場合に最適であり,よりよい生存のために変化統計に一致する比率で最適です.
科学分野:
- 進化生物学の進化生物学について
- 理論的な生態学
- 人口の動態
背景:
- 生物は変動する環境に直面し,生き残るために行動的適応を必要とする.
- クローン集団は,適応のために感知応答またはストキャスティック現象型スイッチングを使用します.
- これらの戦略の間のトレードオフは完全に理解されていません.
研究 の 目的:
- 変動する環境におけるセンシングよりも,ストキャスティック現象型のスイッチングが好まれる時期を判断する.
- 環境の変化に適応する生物の最適な切り替え率を特定する.
- 生物の成長率と環境情報との関係を確立する.
主な方法:
- 変動する環境における人口動態の数学モデリング.
- 適応戦略の分析:センシング対ストキャスティックスイッチング.
- 環境変化の統計に基づく最適の切り替え率の推論.
主要な成果:
- ストキャスティック・スイッチングは,環境の変化が頻度が低いときの感知よりも好ましい.
- 最適なスイッチング率は,環境変化の統計と直接関係しています.
- 長期的な成長率と環境情報との間には,定量的な関係が生じました.
結論:
- ストキャスティック現象型スイッチングは,変動する環境で実行可能で,時には優れた適応戦略です.
- 環境の予測可能性は,クローン集団の最適な適応戦略に影響を与えます.
- 環境情報と成長率の関連性を理解することは,生物の適応を予測する上で極めて重要です.
関連する概念動画
00:57Population Growth
Population size is dynamic, increasing with birth rates and immigration, and decreasing with death rates and emigration. In ideal conditions with unlimited resources, populations can increase exponentially, which plots as a J-shaped growth rate curve of population size against time. This type of curve is characteristic of newly-introduced invasive species, or populations that have suffered catastrophic declines and are rebounding.However, realistic environmental conditions limit the number of...
01:09Mutation, Gene Flow, and Genetic Drift
In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).Mechanisms of Genetic VariationThe original sources of genetic variation are mutations,...
03:33Genetic Drift
Natural selection—probably the most well-known evolutionary mechanism—increases the prevalence of traits that enhance survival and reproduction. However, evolution does not merely propagate favorable traits, nor does it always benefit populations.Life is not fair. A deer grazing contentedly in a field can have her meal cut tragically short by a bolt of lightning. If the doomed doe is one of only three in the population, 1/3 of the population’s gene pool is lost. Random events like this can...
01:26Exponential Equations for Modeling Growth
Exponential models are essential for describing rapid, multiplicative changes in natural systems, such as population growth. When a population doubles at regular intervals, the process can be modeled using a suitable base. For instance, a bacterial culture that doubles every three hours follows the model n(t)=n0⋅2t/3, where n(t) is the population at the time t.A more general model uses the natural base e, especially for continuous growth. This takes the form n(t)=n0⋅ert, where r is the relative...
01:25Modeling with Differential Equations
Population dynamics can be described mathematically by considering the population size P(t) as a function of time. The rate of change of the population is then represented by the derivative of P(t). A simple assumption is that the rate of growth is proportional to the size of the population itself. This leads to an exponential growth model, where the population increases rapidly without bound. While this is a useful first approximation, it does not reflect realistic long-term...
01:28Infectious Diseases and Their Occurrence
Infectious diseases appear in populations through various transmission patterns, influenced by pathogen characteristics, population immunity, environmental conditions, and social behavior. Understanding these patterns is essential for effective public health surveillance and intervention. These categories—sporadic, outbreak, epidemic, pandemic, and endemic—help frame the nature and scope of disease events.Sporadic diseases occur irregularly and infrequently, without a predictable temporal or...