Fitness

Definition

Fitness refers to an organism's ability to survive and reproduce in a given environment, which is a key driver of evolution. It encompasses various aspects, including physical, physiological, and behavioral characteristics that enhance an individual's chances of passing on their genetic material to future generations.

5 Must Know Facts For Your Next Test

1. Fitness is a relative concept, as an individual's fitness is determined by their ability to survive and reproduce compared to other members of the same population.
2. Organisms with higher fitness are more likely to pass on their genetic traits to the next generation, leading to the gradual evolution of the population.
3. Fitness can be influenced by a wide range of factors, including physical traits, behavioral adaptations, and environmental conditions.
4. Fitness is not a static property, as it can change over time as the environment and the composition of the population shifts.
5. The concept of fitness is central to the theory of evolution by natural selection, as it explains how certain traits become more or less common in a population over successive generations.

Review Questions

• Explain how fitness is defined in the context of evolution and how it relates to the process of natural selection.
  • In the context of evolution, fitness refers to an organism's ability to survive and reproduce in a given environment, which is a key driver of natural selection. Organisms with higher fitness are more likely to pass on their genetic traits to the next generation, leading to the gradual evolution of the population. Fitness is a relative concept, as an individual's fitness is determined by their ability to survive and reproduce compared to other members of the same population. The concept of fitness is central to the theory of evolution by natural selection, as it explains how certain traits become more or less common in a population over successive generations.
• Describe how different factors can influence an organism's fitness and how these factors can change over time.
  • Fitness can be influenced by a wide range of factors, including physical traits, behavioral adaptations, and environmental conditions. For example, an organism's size, speed, strength, or camouflage may enhance its ability to evade predators or obtain resources, thereby increasing its fitness. Behavioral adaptations, such as social cooperation or parental care, can also improve an organism's chances of survival and reproduction. Additionally, changes in the environment, such as the availability of resources or the presence of new predators, can alter the relative fitness of different traits within a population. As the environment and the composition of the population shift, the factors that contribute to an organism's fitness can also change over time.
• Analyze how the concept of fitness is central to the theory of evolution by natural selection and how it drives the gradual evolution of populations.
  • The concept of fitness is central to the theory of evolution by natural selection, as it explains how certain traits become more or less common in a population over successive generations. Organisms with higher fitness, meaning they are better able to survive and reproduce in their environment, are more likely to pass on their genetic traits to the next generation. This process of natural selection leads to the gradual evolution of the population, as the more fit individuals contribute a greater proportion of the gene pool. Over time, this can result in the emergence of new adaptations and the disappearance of less fit traits, as the population becomes better suited to its environment. The constant interplay between an organism's fitness and the selective pressures of its environment is a driving force behind the ongoing process of evolution.

Related terms

Natural Selection: The process by which certain traits become either more or less common in a population based on their relative fitness and contribution to reproductive success.

Adaptation: A heritable characteristic that improves an organism's ability to survive and reproduce in its environment.

Reproductive Fitness: The ability of an organism to produce offspring that survive to reproductive age, which is a key measure of evolutionary fitness.