normalizing selection

简明释义

正态选择

英英释义

例句

1.When studying the effects of normalizing selection, researchers found that populations tend to stabilize around an optimal phenotype.

在研究正常化选择的影响时，研究人员发现种群往往围绕最佳表型稳定。

2.The concept of normalizing selection is crucial in understanding how certain traits become fixed in a population.

理解某些特征如何在种群中固定的过程时，正常化选择的概念至关重要。

3.In many bird species, normalizing selection helps maintain consistent plumage colors that are advantageous for camouflage.

在许多鸟类中，正常化选择有助于保持有利于伪装的一致羽毛颜色。

4.In a stable environment, organisms often undergo normalizing selection, which favors average traits over extremes.

在一个稳定的环境中，生物通常会经历正常化选择，这使得平均特征比极端特征更受青睐。

5.A classic example of normalizing selection can be seen in human birth weights, where very low or very high weights are less common.

人类出生体重的一个经典例子是正常化选择，在这种情况下，过低或过高的体重较少见。

作文

In the study of evolution, various mechanisms drive the adaptation of species to their environments. One of the most significant mechanisms is known as normalizing selection, which plays a crucial role in maintaining the stability of a population's traits. This form of natural selection favors the average individuals within a population while selecting against extreme variations. As a result, normalizing selection helps to reduce phenotypic variation and ensures that the population remains well-suited to its environment. To understand normalizing selection, it is essential to consider how it contrasts with other forms of natural selection, such as directional and disruptive selection. Directional selection occurs when one extreme phenotype is favored over others, leading to a shift in the population's trait distribution. In contrast, disruptive selection favors extreme phenotypes at both ends of the spectrum, potentially leading to speciation. However, normalizing selection focuses on preserving the status quo by promoting traits that are already prevalent within the population.An excellent example of normalizing selection can be found in the case of human birth weights. Studies have shown that infants with average birth weights tend to have higher survival rates compared to those with very low or very high weights. This phenomenon suggests that both underweight and overweight infants face greater risks of health complications and mortality. Consequently, normalizing selection operates to favor those newborns who fall within the average range, ensuring that the population's overall health and viability remain stable over generations.Another instance of normalizing selection can be observed in the coloration of certain animal species. For example, in a population of rabbits living in a snowy environment, those with fur that closely matches the surrounding habitat are more likely to survive and reproduce. If the population contains rabbits with either very light or very dark fur, these extremes may be more easily spotted by predators, resulting in lower survival rates. Over time, normalizing selection would favor the rabbits with fur colors that blend seamlessly into their environment, promoting a more uniform appearance within the population.The implications of normalizing selection extend beyond individual species and can influence entire ecosystems. By favoring average traits, this type of selection contributes to the resilience of populations in the face of environmental changes. When a species exhibits a wide range of phenotypic diversity, it may be better equipped to adapt to new challenges, such as shifting climates or emerging diseases. However, normalizing selection can limit this diversity by consistently favoring the average traits, potentially making populations more vulnerable to sudden changes in their environment.In conclusion, normalizing selection is a fundamental concept in evolutionary biology that emphasizes the importance of average traits within populations. By understanding how this mechanism operates, we gain valuable insights into the dynamics of natural selection and the factors that contribute to the stability and adaptability of species. As we continue to explore the complexities of evolution, recognizing the role of normalizing selection will help us appreciate the delicate balance of nature and the ongoing processes that shape the living world around us.

在进化研究中，各种机制推动物种适应其环境。其中一个最重要的机制被称为正常选择，它在维持种群特征的稳定性方面发挥着关键作用。这种自然选择形式青睐种群中的平均个体，同时对极端变异进行选择。因此，正常选择有助于减少表型变异，确保种群适合其环境。要理解正常选择，必须考虑它与其他自然选择形式的对比，例如方向选择和破坏性选择。方向选择发生在一个极端表型优于其他表型时，导致种群特征分布的转变。相反，破坏性选择青睐两个极端表型，可能导致物种形成。然而，正常选择专注于通过促进已经普遍存在于种群中的特征来保持现状。正常选择的一个很好的例子可以在人的出生体重案例中找到。研究表明，平均出生体重的婴儿相较于体重过轻或过重的婴儿，生存率更高。这一现象表明，体重过轻和过重的婴儿面临更大的健康并发症和死亡风险。因此，正常选择运作以青睐那些处于平均范围内的新生儿，确保种群的整体健康和生存能力在几代人中保持稳定。另一个观察到的正常选择实例可以在某些动物物种的颜色中看到。例如，在生活在雪地环境中的兔子种群中，那些毛色与周围栖息地相近的兔子更有可能生存和繁殖。如果种群中有毛色非常浅或非常深的兔子，这些极端可能更容易被捕食者发现，导致生存率降低。随着时间的推移，正常选择将青睐那些毛色与环境无缝融合的兔子，促进种群外观的更加统一。正常选择的影响超越了个别物种，可能影响整个生态系统。通过青睐平均特征，这种选择类型有助于种群在面对环境变化时的韧性。当一个物种表现出广泛的表型多样性时，它可能更好地适应新的挑战，例如气候变化或新出现的疾病。然而，正常选择可能通过持续青睐平均特征限制这种多样性，从而使种群在突发环境变化时更容易受到影响。总之，正常选择是进化生物学中的一个基本概念，强调种群中平均特征的重要性。通过理解这一机制的运作，我们获得了对自然选择动态及其对物种稳定性和适应性贡献因素的宝贵见解。随着我们继续探索进化的复杂性，认识到正常选择的作用将帮助我们欣赏自然的微妙平衡以及塑造我们周围生物世界的持续过程。