Adaptation and Natural Selection Quiz

Adaptation and Natural Selection

• Adaptation is the process by which natural selection leads to traits improving an organism's fit with its environment, enhancing survival and reproduction. This is essentially synonymous with natural selection.
• The Jamaican bromeliad crab's life cycle occurs entirely on bromeliads. Females maintain oxygen levels and pH in water pools where they raise young, showcasing adaptation.

Exaptations

• Exaptations are structures currently functioning as adaptations, but originally evolved for different reasons and later co-opted.
• They don't imply goal-oriented evolution or anticipation of future needs; only current environmental improvement is considered.
• Bird feathers, initially evolving before flight, are an example of an exaptation.

Acclimation/Acclimatization

• Acclimation is an individual organism's adjustment to environmental change, minimizing stressor effects and maintaining performance. It's rapid, reversible, and non-heritable.
• Adaptation, in contrast, involves heritable phenotypic change in populations across generations via natural selection. Individuals cannot evolve; only populations can.
• High-altitude populations exhibit both acclimatization (reversible physiological changes) and adaptation (heritable changes in populations). Tibetans and Andeans show different adaptive strategies to high altitude.

Complex Adaptations and Exaptations

• Complex structures can be co-opted from existing structures or pathways.
• Treehoppers' helmet-like structures, for example, show similarities to wings and share key developmental genes.

Imperfect Adaptations

• Darwinian demons—ideal organisms maximizing all fitness aspects—don't exist due to several factors.
• Existing variation limits selection, leading to a waiting game for favorable mutations.
• Environmental change makes previous adaptations obsolete. Organisms interact, leading to selection pressures that can undermine adaptations in other species.
• Genetic drift, gene flow, and mutation can also lead to maladaptation. Gene flow into a population can hinder local adaptation. Founder effects may lead to loss of genetic variation or fixation of deleterious traits. Genetic drift may increase deleterious alleles or decrease beneficial ones.

Practice Questions

• Human skull sutures: suggest the sutures' existence predates compression for childbirth, the trait's adaptation is for an entirely different current functionality.
• Detecting Adaptation: Identify methods of identifying the evolutionary process of adaptation within populations.
• Maladaptation: Identify the factors that lead to maladaptation occurring within populations.

Test your knowledge on adaptation, natural selection, and exaptations. This quiz covers how organisms adapt to their environments and the concepts of acclimation. Explore real-world examples, such as the Jamaican bromeliad crab and bird feathers, to deepen your understanding.