密度サイクルと自然選択によって導かれる子孫の量と質のゲームです
B Sinervo1, E Svensson, T Comendant
1Department of Ecology and Evolutionary Biology, University of California, Santa Cruz 95064, USA. sinervo@biology.ucsc.edu
Nature
|September 13, 2000
まとめ
自然淘汰は,人口密度に基づいて,異なるトカゲの生殖戦略を好む. 遺伝的差異によって引き起こされるこの進化のゲームは,安定した2世代の人口サイクルにつながります.
科学分野:
- 進化生物学の進化生物学について
- エコロジー エコロジー エコロジー
- 人口のダイナミクス
背景:
- ある仮説によると,自然選択は,人口密度の周期中に,女性の生殖戦略を好むという.
- 低密度では,選択は多くの小さな子孫 (r-戦略家) を好むが,高密度では,選択はより少ない大きな子孫 (K-戦略家) を好む.
研究 の 目的:
- 安定した人口サイクルを駆動する遺伝的r-vs-K選択ゲームの最初の経験的証拠を提供すること.
- 密度依存選択がの繁殖戦略と集団動態にどのように影響するか調査する.
主な方法:
- 異なる喉の色変形を持つトカゲの10年間のフィットネス研究を実施しました.
- 人口密度によって異なる選択圧力を分析するためにゲーム理論を用いた.
- 稀な子と一般的な子を導入することによって,子孫のサイズに周波数依存の選択をテストしました.
主要な成果:
- 喉の色変形 (r-戦略家としてオレンジの喉,K-戦略家として黄の喉) に関連した2つの異なる女性生殖戦略を特定しました.
- 選択の強さは人口密度によって変化し,低密度ではオレンジ色の形態,高密度では黄色い形態を好むことが示された.
- 子孫のサイズに対する否定的な周波数依存の選択が確認され,より大きな幼生は稀である場合に生存の利点を持つ.
結論:
- 内部的な周波数と密度に依存する選択メカニズムは,進化的なゲームを駆動する.
- このゲームは,明確なrとK戦略を通じて,タカの安定した2世代の人口サイクルを促進します.
- この発見は,密度依存の選択が異なる生殖戦略を好むという仮説を裏付けている.
関連する概念動画
Life Histories
Constrained by limited energy and resources, organisms must compromise between offspring quantity and parental investment. This trade-off is represented by two primary reproductive strategies; K-strategists produce few offspring but provide substantial parental support, whereas r-strategists produce much progeny that receives little care. These strategies are related to an organism’s survival likelihood across its lifespan, which is represented by a survivorship curve. Three general types of...
Population 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...
What is Natural Selection?
Natural selection is an evolutionary process in which individuals with survival-promoting traits reproduce at higher rates. These favorable traits become more common within a population or species. Naturally selected traits initially arise via random genetic mutations. In order for selection to occur, there must be variation within a population, the trait controlling the variation must be heritable, and there must be an evolutionary advantage for variation in the trait.The Theory of Natural...
Types of Selection
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
Mutation, 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,...
Limits to Natural Selection
Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.For one, natural selection can only act upon existing genetic variation. Hypothetically, redtusks may enhance elephant survival by deterring ivory-seeking poachers. However, if there are no gene variants—or alleles—for redtusks, natural selection cannot increase the prevalence of...


