evolution webquest answer key pdf Doc Template | pdfFiller - Free Printable

Let’s go step by step through the worksheet. This is about evolution, and you’re being asked to visit a website (pbs.org/evolution) and answer questions based on what you find there. Since I can’t browse the web live, I’ll use my knowledge of that PBS Evolution site (which is well-known and has consistent content) to give you accurate answers based on how the site is structured.

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A. Click on “Evolution 101.” Click on “An Introduction to Evolution”

1. Simply put, biological evolution is:
→ Biological evolution is the change in living things over time. It means that species today are different from their ancestors because they’ve changed gradually across many generations.

2. What is the central idea of evolution?
→ The central idea is that all life on Earth shares common ancestors, and over long periods of time, populations of organisms change — sometimes becoming new species. This happens through natural selection and other processes.

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B. Click on “Mechanisms” which is on the side of the page. Then Click “Natural Selection” in the bottom right corner

1. Evolution only occurs when there is a change in __________ within a __________ over time.
→ Evolution only occurs when there is a change in genes (or genetic traits) within a population over time.

2. Which of the two scenarios is an example of evolution occurring?
*(Note: On the PBS site, this section usually shows two examples — one where individuals adapt during their lifetime vs. one where a population changes genetically over generations.)*
→ The correct example is the one where a population’s traits change over generations due to inherited differences — for instance, if beetles with darker shells survive better and pass those genes on, so over time more beetles are dark-shelled. That’s evolution. The other scenario (like a single animal getting stronger or changing color during its life) is NOT evolution — because it’s not passed down genetically.

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C. Click “Next”

What are the four processes for evolutionary change?
These are the main mechanisms that cause evolution:

1. Mutation – Random changes in DNA that create new traits.
2. Gene Flow – When genes move between populations (like animals migrating and breeding).
3. Genetic Drift – Random changes in gene frequencies, especially in small populations.
4. Natural Selection – Traits that help survival and reproduction become more common over time.

*(Sometimes “non-random mating” is included, but the standard four taught at this level are mutation, gene flow, genetic drift, and natural selection.)*

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D. Click “Next”

Genetic variation is key to evolutionary change. What are the three sources of genetic variation?

1. Mutations – Changes in DNA sequence.
2. Sexual Reproduction – Mixing of genes from two parents creates new combinations.
3. Gene Flow – Movement of genes between populations introduces new variations.

*(Some sources list “recombination during meiosis” as part of sexual reproduction, but for simplicity, these three are commonly accepted.)*

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Final Answer:

A.
1. Biological evolution is the change in living things over time.
2. The central idea is that all life shares common ancestors and changes over generations through natural selection and other processes.

B.
1. Evolution only occurs when there is a change in genes within a population over time.
2. The example where a population’s inherited traits change over generations (e.g., darker beetles becoming more common) is evolution.

C. Four processes for evolutionary change:
1. Mutation
2. Gene Flow
3. Genetic Drift
4. Natural Selection

D. Three sources of genetic variation:
1. Mutations
2. Sexual Reproduction
3. Gene Flow