Question

What do you consider to be the essential distinction between natural selection and evolution?

Short answer

Natural selection is a mechanism of evolution; evolution is the process of genetic change in populations.

Step-by-step solution

Define Natural Selection

Natural selection is a process by which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. It is one of the mechanisms of evolution that increases the frequency of advantageous traits in a population.

Define Evolution

Evolution refers to the change in the genetic composition of a population over successive generations. It encompasses various mechanisms, including mutation, gene flow, genetic drift, and natural selection, which contribute to changes in the population's genetic makeup over time.

Distinguish Between the Two

The essential distinction between natural selection and evolution is their scope. Natural selection is a mechanism of evolution that explains how beneficial traits become more common in a population. In contrast, evolution refers to the overall change in the genetic makeup of populations over time, driven by natural selection and other mechanisms.

Key concepts

Natural Selection

Natural selection is a fundamental concept in understanding the process of evolution. It explains how certain traits become more common in a population over time. These traits are usually advantageous, meaning they help an organism survive and reproduce in its environment. For example, if a particular bird has a beak that is better suited for accessing food, it is more likely to survive and pass on this beneficial trait to its offspring.
Over many generations, natural selection can lead to significant changes in a species. This process is not random; instead, it relies on existing variations within a population. It effectively "selects" traits that aid survival and reproduction.

• Natural selection works by favoring inherited traits that boost an organism's chances of survival.
• It increases the prevalence of advantageous traits, affecting how a species evolves over time.
• This process is one of several mechanisms by which evolution occurs.

Understanding natural selection is crucial to grasping how species adapt to their environments and continue to evolve.

Genetic Composition

The genetic composition of a population refers to the mix of genetic information that determines specific traits within that population. It includes genes shared among individuals and the variety of alleles (different forms of a gene) present. Genetic composition is the basis for a population's ability to evolve, as it provides the variation that natural selection acts upon.
This composition changes over time due to several evolutionary mechanisms such as mutation, which introduces new genetic variations. Another cause is gene flow, which occurs when individuals migrate from one population to another, altering the allele frequencies in each.

• Mutation introduces new genetic changes, adding to genetic diversity.
• Gene flow can introduce new alleles and variations from neighboring populations.
• Genetic drift, a random process, can also affect allele frequencies, especially in small populations.

These factors work together, leading to changes in a population’s genetic composition, which is the foundation for evolution.

Mechanisms of Evolution

Evolution is the change in the genetic makeup of a population over generations. Several key mechanisms drive this process, each contributing in different ways. The best-known mechanism is natural selection, where advantageous traits become more common as organisms with those traits have better survival and reproductive success.
Other mechanisms also play vital roles in shaping evolution. Mutation is one such mechanism, introducing new genetic material into a population, creating genetic variation. Gene flow and genetic drift are equally important, influencing allele frequencies in various ways.

• Natural Selection: Increases frequency of beneficial traits, shaping adaptation to environments.
• Mutation: Adds new genetic variations, providing raw material for evolution.
• Gene Flow: Transfers alleles between populations, contributing to genetic diversity.
• Genetic Drift: Causes random changes in allele frequencies, especially in small populations.

Through these mechanisms, populations evolve, adapting to their environments and sometimes giving rise to new species.