Question

Natural selection is the name given to (a) the occasional mutations that occur in DNA; (b) the mechanism by which advantageous traits are preferentially passed on from parents to offspring; (c) the idea that organisms can develop new characteristics during their lives and then pass these to their offspring.

Short answer

Natural selection is (b) the mechanism by which advantageous traits are preferentially passed on from parents to offspring.

Step-by-step solution

Identify the Concept

Natural selection is a fundamental concept in biology and refers to a specific process. We need to identify which option best aligns with the well-known definition of natural selection.

Understand Option A

Option (a) states that natural selection is the occasional mutations that occur in DNA. While mutations are a part of the evolutionary process, they are not what is meant by natural selection itself.

Analyze Option B

Option (b) suggests that natural selection is the mechanism by which advantageous traits are preferentially passed on from parents to offspring. This aligns closely with the scientific understanding of natural selection, where advantageous traits increase the likelihood of survival and reproduction.

Evaluate Option C

Option (c) proposes that natural selection is about developing new characteristics during an organism's life and passing them to offspring. This concept resembles Lamarckian evolution, which differs from natural selection.

Make a Decision

After evaluating all the options, we conclude that option (b) best represents the concept of natural selection as it describes the preferential passing of advantageous traits.

Key concepts

Evolutionary Biology

Evolutionary biology is the study of how life evolves and diversifies over time. It's like a detective story uncovering the secrets of life’s history. The main aim of evolutionary biology is to understand the mechanisms that drive the evolutionary process.
This includes studying how traits change in populations and how these changes lead to the diversity of life we see today.

• Evolution is typically driven by four key processes: mutation, genetic drift, gene flow, and natural selection.
• Natural selection is perhaps the most famous, acting like nature’s quality control, favoring traits that improve survival and reproduction.

Overall, evolutionary biology gives us the tools to understand why species are the way they are today and how they might continue to change in the future.

DNA Mutations

DNA mutations are random changes in the genetic code, which can happen for several reasons, like errors during cell division, or due to environmental factors. These mutations are essential for evolution because they introduce new genetic variations.
Without these variations, evolution would not occur because natural selection wouldn't have any diversity to work with.

• Most mutations do not have an effect on the organism, but some can lead to new traits, which might be advantageous or disadvantageous.
• Beneficial mutations can lead to traits that improve an organism's chance of survival, whereas harmful mutations may reduce these chances.

In essence, mutations are the raw material upon which natural selection acts, driving the evolutionary change.

Lamarackian Evolution

Lamarckian evolution, proposed by Jean-Baptiste Lamarck, is an older theory of evolution. It suggested that organisms could acquire traits during their lifetime and directly pass these traits to their offspring. For example, a giraffe stretching its neck for food would supposedly pass on a longer neck to its offspring.
This idea is quite different from natural selection and modern genetic understanding.

• Lamarck's theory was largely based on use and disuse, meaning if a trait was used, it would develop, while unused traits would diminish.
• While interesting, this theory does not hold up to scientific scrutiny because traits acquired during an organism's life do not alter its DNA.

Despite its initial appeal, Lamarckian evolution has been largely replaced by our current understanding of genetic inheritance.

Advantageous Traits

Advantageous traits are characteristics that improve an organism's chances of survival and reproduction in its environment. These traits often develop because they confer some benefit that makes individuals more successful.
These successful individuals are more likely to pass these favourable traits onto their offspring through natural selection.

• Examples of advantageous traits might include a faster running speed to evade predators, or a certain coloration that makes an animal less visible to predators.
• Over many generations, advantageous traits can dominate a population, which is a fundamental process in evolution.

This preferential passing of beneficial traits is a key mechanism by which populations adapt to their changing environments over time.