Question

Evolution ________________ . a. is change in a line of descent b. is the same as natural selection c. is the goal of natural selection d. explains the origin of life

Short answer

a. is change in a line of descent

Step-by-step solution

Understand the Definition of Evolution

Evolution refers to the change in the heritable characteristics of biological populations over successive generations. This process is driven by mechanisms like natural selection, genetic drift, mutation, and gene flow.

Analyze the Options A and B

Option a suggests evolution is `change in a line of descent`, which aligns with the definition of evolution as change over generations. Option b suggests evolution is the `same as natural selection`, which is incorrect because natural selection is a mechanism of evolution, not synonymous with it.

Review Options C and D

Option c suggests evolution is `the goal of natural selection`, which is incorrect because natural selection does not have goals; it is a process that results in evolution. Option d claims evolution `explains the origin of life`, which is incorrect as evolution pertains to the development of life after it begins, not its origin.

Select the Correct Answer

Based on the analysis, option a, "is change in a line of descent," accurately describes evolution as it aligns with how evolution is defined.

Key concepts

Natural Selection

Natural selection is a key mechanism of evolution. It works like nature's filter, allowing individuals with advantageous traits to survive and reproduce more than those without them. This "survival of the fittest" concept means that over time, the traits that aid survival become more common in a population.
This doesn't happen overnight. It's a gradual process where favorable traits accumulate in a population. These traits can include physical features, such as faster running speed, or behavioral traits, like better hiding strategies.
The conditions of the environment determine which traits are beneficial. So if the environment changes, what is considered "advantageous" may also change. As a result, natural selection is a dynamic process that promotes adaptation and diversity in life forms.

Genetic Drift

Genetic drift is another mechanism that influences evolution, but unlike natural selection, it is random. Genetic drift occurs due to chance events that change the frequency of genes in a small population. It doesn't necessarily lead to adaptations or improve survival chances.
For instance, if a few individuals with unique traits are wiped out by a random event, like a natural disaster, those traits may disappear from the population. In small populations, genetic drift can have a significant effect because each individual's genetic contribution is proportionally larger.

• This randomness introduces variability by altering gene frequencies unpredictably.
• Over time, genetic drift can lead to populations that are genetically distinct from each other, even if they started identically.

This process highlights how chance can shape the future genetic make-up of populations.

Mutation

Mutations are changes in the DNA sequence of an organism's genome and represent the primary source of genetic diversity. While many mutations are neutral, some can affect an organism's ability to survive and reproduce.
Mutations occur constantly and can be caused by various factors, including errors during DNA replication, exposure to radiation, or certain chemicals. Even though most are harmless or even corrected by DNA repair mechanisms, a few can have significant impacts.

• Beneficial mutations might give an organism an advantage, increasing its chances of surviving and reproducing.
• Harmful mutations can reduce those chances.

Without mutation, evolution would not have the raw material needed to cultivate diversity or drive adaptation to changing environments.

Gene Flow

Gene flow, also known as gene migration, is the transfer of genetic material between separate populations. It acts as a mixing tool, introducing new genetic variations and preventing populations from becoming genetically isolated.
When individuals from one population breed with individuals from another, they transfer their genes, adding to the genetic diversity. This can have several effects:

• Gene flow increases diversity within a population, helping it stay adaptable and resilient to environmental changes.
• It can also reduce differences between populations, potentially slowing down speciation — the formation of new species.

It's essential in evolutionary processes, as it allows beneficial traits to spread across populations, enhancing their adaptive potential.