Question

By avoiding being eaten, \(B\). trifoliolata individuals would have increased fitness. In biology, what does the term "fitness" mean?

Short answer

In biology, "fitness" refers to an individual's ability to survive, reproduce, and pass on its genes to the next generation. It is a crucial factor in the process of natural selection, as it determines the success of an organism within its environment. In the case of B. trifoliolata individuals, their ability to avoid being eaten would increase their fitness, as they would have a better chance at surviving to reproduce and passing on the traits that allowed them to avoid predation.

Step-by-step solution

Define Fitness in Biology

In biology, the term "fitness" refers to an individual's ability to survive, reproduce, and pass on its genes to the next generation. This concept is at the heart of evolution, as those individuals with higher fitness are more likely to contribute to the gene pool of future generations.

Explain the Importance of Fitness

Fitness is a crucial factor in the process of natural selection, as it determines the success of a particular organism within its environment. This success is measured not only by the survival of the individual, but also by its ability to produce offspring that will carry on the traits that contributed to its higher fitness level. Over time, traits that improve fitness will become more common in the population, while less-fit traits will diminish.

Connect Fitness to the Given Example

In the case of B. trifoliolata individuals, their ability to avoid being eaten would indeed increase their fitness. By successfully avoiding predation, these individuals would have a better chance at surviving to reproduce and passing on the traits that allowed them to avoid being eaten. This increased fitness would have a positive effect on the overall population of B. trifoliolata, as the traits related to avoiding predation would become more prevalent over time.

Key concepts

Natural Selection

Natural selection is a fundamental biological process that drives evolution over time. It involves the survival and reproduction of those individuals in a population that are best suited to the current environment. Imagine a scenario where a particular bird species feeds on insects, and the insects have various shades of color: some are green, others brown. If these birds can more easily spot the green insects against their natural habitat, the brown insects have a higher chance of surviving and reproducing. Over time, the brown color trait becomes more common, simply because brown insects are less likely to be eaten. This is a perfect example of natural selection at work.

Natural selection operates on traits that affect an organism's fitness, allowing beneficial traits to accumulate within a population. Fitness-enhancing traits might include camouflage, increased speed, or even behavioral adaptations that improve survival prospects. Natural selection thus ensures that populations can adapt to their environments, and this continuous process can lead to the development of new species.

Evolution

Evolution is the gradual change in the genetic composition of populations over successive generations. It's a process powered by natural selection, where advantageous traits become more common in a population. One way to visualize this is to think of a family tree that stretches back for countless generations. As it grows, it branches out, with each branch potentially representing a new trait or even a new species.

Let's consider an example: a population of rabbits living in a snowy environment. Over time, rabbits with whiter fur—despite starting as a minority—may survive predation better and reproduce more than their darker-furred kin because of camouflage. As generations pass, the rabbit population becomes predominantly white, reflecting this evolutionary shift.

Evolution doesn't occur in isolation; it relies on several mechanisms, including mutation, genetic drift, and gene flow, not just natural selection. Each of these factors can change the gene pool of a population, contributing to evolutionary change.

Reproduction

Reproduction is the biological process through which new individual organisms are produced. It's a crucial aspect of evolution because, without reproduction, there can be no transfer of genes from one generation to the next. There are two main types of reproduction: sexual and asexual.

In sexual reproduction, two parents contribute genetic material to produce genetically diverse offspring. This diversity is advantageous in changing environments because it increases the likelihood that some offspring will possess traits favorable for survival. On the other hand, asexual reproduction involves a single organism producing offspring identical to itself, ideally suited for stable environments.

Reproduction not only ensures the continuation of a species but also enables genetic variations that drive evolution. Through the recombination of genes in sexual reproduction or mutations in asexual organisms, new traits can emerge, further influencing a species' evolutionary path.

Gene Pool

The gene pool is the complete set of genetic information in the population. It encompasses all the alleles—the different versions of genes—that are present. A rich and diverse gene pool indicates a healthy population, capable of adapting to various environmental challenges.

For example, a population of wildflowers has a vast gene pool if there are many different colors, sizes, and shapes of flowers. This genetic diversity can help the population adapt if the environment changes, such as when a new insect pest arrives. Some flower variations might be less palatable to the pest, allowing those individuals to survive and reproduce, shifting the makeup of the population over generations.

A gene pool is not static; it can change due to factors such as genetic mutations, migration, genetic drift, and selection pressures. The variations within a gene pool are crucial for the long-term survival of a species, offering a buffer against extinction by supplying adaptable traits.