Evidence of Evolution Worksheet featuring matching exercises, diagram identification, and vocabulary fill-in-the-blank questions.

Let’s go step by step to solve this worksheet. We’ll match each term with its correct definition or diagram, and then fill in the blanks using the vocabulary box.

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Part 1: Match terms to definitions (Questions 1–5)

We are given 5 terms and 5 lettered definitions (a–e). Let’s think about what each term means:

1. vestigial structure → These are body parts that have shrunk over time because they’re no longer needed. Example: human tailbone.
→ That matches e) “structures that have reduced in size because they no longer serve an important function”

2. homologous structures → These are similar bones in different animals that show common ancestry — like arm bones in humans, bats, whales.
→ That matches c) “related organisms have the same bone makeup.”

3. DNA sequence → This is the order of nucleotides in DNA. Comparing these shows how closely related species are.
→ That matches b) “similarities and differences in nucleotide sequences between organisms.”

4. fossil record → Fossils are remains of dead organisms from long ago. The fossil record is all those collected fossils.
→ That matches a) “remains of dead organisms”

5. embryology → Study of embryos. In early development, many animals look alike (like dogs, pigs, humans).
→ That matches d) “in the early stages of development dogs, pigs, and humans resemble one another.”

So for Part 1:
1. e
2. c
3. b
4. a
5. d

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Part 2: Match terms to diagrams (Questions 6–9)

Now we match the same 4 terms (plus embryology) to diagrams labeled a, b, c, d.

Look at the diagrams:

- Diagram a) shows embryos of different animals looking very similar → that’s embryology
- Diagram b) shows limb bones changing over millions of years → that’s showing evolution of limbs → transitional fossil? Wait — actually, it’s showing homologous structures evolving over time. But let’s check labels. Actually, diagram b has “Modern Day” vs “Millions of years ago” — so it’s showing change over time → likely transitional fossil evidence? Hmm. Wait — let’s reassign carefully.

Actually, let’s label them properly:

Diagram a) = embryos → embryology

Diagram b) = comparing forelimbs across species (human, bat, whale, etc.) → classic example of homologous structures

Diagram c) = skeleton of ancient fish-like creature with arrow pointing to leg-like fin → this is a transitional fossil (between fish and land animals)

Diagram d) = shows Coelacanth fin turning into tetrapod leg → also transitional, but wait — question 8 is “transitional fossil”, and diagram c is clearly a fossil skeleton. Diagram d is more about anatomical transition, but still could be considered transitional. However, looking at standard curriculum:

Usually:
- Embryos → embryology → diagram a
- Limb comparison → homologous structures → diagram b
- Ancient skeleton with mixed features → transitional fossil → diagram c
- Vestigial structure? None of these directly show vestigial... Wait — maybe diagram d includes something? Actually, diagram d shows evolution of limb from fin — not vestigial.

Wait — perhaps I misread. Let’s list again:

Terms to match:
6. vestigial structure
7. homologous structures
8. transitional fossil
9. embryology

Diagrams:
a) embryos → embryology → #9
b) limb bones across species → homologous structures → #7
c) fossil skeleton with arrow → transitional fossil → #8
d) fin to leg evolution → this might be illustrating transitional forms too, but since c is already taken, and d doesn’t fit vestigial… Hmm.

Wait — maybe diagram d is meant to show vestigial? No, it shows functional change.

Actually, looking back — there’s no diagram explicitly showing a vestigial structure (like whale pelvis or human appendix). So perhaps the matching is:

But let’s check standard answers for such worksheets.

Typically:
- Diagram a (embryos) → embryology
- Diagram b (limb bones) → homologous structures
- Diagram c (ancient skeleton) → transitional fossil
- Diagram d (fin to leg) → also transitional? Or maybe it's meant for vestigial? Doesn't fit.

Wait — perhaps I made a mistake. Let me re-express:

Actually, in many textbooks:
- Homologous structures: diagram b (same bone pattern)
- Transitional fossil: diagram c (Tiktaalik or similar)
- Embryology: diagram a
- Vestigial structure: none shown? But question 6 is vestigial structure — must match one.

Looking at diagram d: it shows Coelacanth fin and Tetrapod Leg — this is about evolutionary transition, not vestigial.

Perhaps the intended matches are:

6. vestigial structure → ? Maybe not pictured? But we have to choose from a,b,c,d.

Wait — perhaps diagram d is meant to illustrate how some structures became reduced? Not really.

Alternatively, maybe diagram b includes vestigial? No.

I think there might be a mismatch, but based on common usage:

Let’s assign as follows (standard answer key style):

6. vestigial structure → ??? Actually, none perfectly fit, but sometimes diagrams include hidden clues. Since we must pick, and diagram d shows reduction? No.

Wait — let’s look again at the original image description.

In diagram d, it says “Coelacanth Fin” and “Tetrapod Leg” — this is showing homology or transition.

Actually, upon second thought — perhaps:

- Diagram a: embryology → 9
- Diagram b: homologous structures → 7
- Diagram c: transitional fossil → 8
- Diagram d: ? For vestigial? Doesn’t fit.

But question 6 is vestigial structure — maybe it’s not represented? That can’t be.

Wait — perhaps I missed: in diagram b, if it shows modern vs ancient, maybe some bones are reduced? Unlikely.

Another idea: sometimes "vestigial" is matched with diagrams showing useless parts, but here none do.

Perhaps the worksheet intends:

Let’s try this logical assignment:

Since diagram c is a fossil skeleton with arrow — definitely transitional fossil → 8

Diagram a: embryos → embryology → 9

Diagram b: comparative anatomy of limbs → homologous structures → 7

That leaves diagram d for vestigial structure? But it doesn’t show vestigial.

Unless... in diagram d, the Coelacanth fin has elements that are precursors, but not vestigial.

I think there might be an error, but for standard purposes, let’s assume:

Actually, reviewing common worksheets, often:

- Vestigial structure is not always paired with a diagram in this set; but since we have to, perhaps diagram d is meant to show evolutionary change where some parts become vestigial later? Stretch.

Wait — let’s read the diagram labels again from your image description:

You said:

d) has Coelacanth Fin and Tetrapod Leg — this is showing how fins evolved into legs — so it’s evidence of evolution via transitional forms, but specifically, it’s illustrating homologous structures or transitional fossils.

But we already assigned homologous to b and transitional to c.

Perhaps diagram d is for vestigial? No.

I recall that in some curricula, the coelacanth is used to show living fossil or transitional, but not vestigial.

Let’s make a decision based on most logical fit:

Given that:

- a = embryos → embryology (9)
- b = limb comparison → homologous structures (7)
- c = fossil skeleton → transitional fossil (8)
- d = ? Only left is vestigial structure (6), even though it doesn’t perfectly fit — perhaps the intention is that some parts in the fin are vestigial in tetrapods? Weak.

Alternatively, maybe diagram b includes vestigial? For example, if one of the limbs has reduced digits? In your description, diagram b has multiple limbs with letters a-e, possibly showing variation.

Upon closer inspection of typical diagrams: diagram b usually shows homologous structures (same bones, different functions), which is #7.

Then for vestigial, perhaps it’s not depicted, but since we must choose, and diagram d shows evolution where some structures may have been lost, but it’s not clear.

I found a better way: let’s search my knowledge base for standard answers.

Standard matching for such worksheets:

- vestigial structure: often not in diagrams, but if forced, sometimes paired with a diagram showing reduced part — none here.
- homologous structures: diagram b
- transitional fossil: diagram c
- embryology: diagram a

So for question 6 (vestigial structure), it might be a trick, but perhaps diagram d is intended for it? Unlikely.

Wait — in diagram d, the Coelacanth fin has bones that are similar to tetrapod leg, but in modern coelacanths, those fins are not used for walking — so they could be considered vestigial for locomotion? Still a stretch.

Perhaps the correct matches are:

6. vestigial structure → d? No.

Let’s look at the answer choices differently.

Another approach: in some versions, diagram d is labeled as showing "evolution of limb" which supports homologous or transitional, but we have separate categories.

I think I need to accept that:

Based on common educational materials:

- Diagram a: embryology → 9
- Diagram b: homologous structures → 7
- Diagram c: transitional fossil → 8
- Diagram d: vestigial structure → 6? Even though it's not accurate, perhaps in this context, it's accepted.

But that feels wrong.

Wait — let's read the user's image description again:

"d) Coelacanth Fin and Tetrapod Leg" — this is typically used to show homologous structures or transitional forms.

Perhaps the worksheet has a mistake, but for the sake of completing, let's assign:

6. vestigial structure — no good match, but if I must, I'll leave it for now.

Actually, I recall that in some worksheets, the vestigial structure is matched with a diagram of whale pelvis or snake legs, which isn't here.

Perhaps diagram b includes a vestigial digit? In the limb diagrams, sometimes one has reduced fingers.

In your description, diagram b has "Modern Day" and "Millions of years ago" with limbs labeled a-e — this might be showing evolutionary change, including reduction.

For example, if in modern day, some digits are missing, that could be vestigial.

So perhaps diagram b is for vestigial structure? But that conflicts with homologous.

This is confusing.

Let me try a different strategy: let's look at the fill-in-the-blank section first, as it might give clues.

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Part 3: Fill in the blank (Questions 10–15)

Vocabulary box:
vestigial structure
radiometric dating
transitional fossil
DNA sequence
plate tectonics
amino acid sequence

Sentences:

"The strongest evidence for evolution is the (10) _______________ and that code can be used to build a(n) (11) _______________."

Strongest evidence is often considered DNA or molecular evidence. "that code" refers to DNA code, so (10) should be "DNA sequence", and (11) "amino acid sequence" because DNA codes for amino acids in proteins.

Next: "When a species has a body part that is no longer useful, like the tail bone in human, that is called a(n) (12) _______________." → Clearly "vestigial structure"

"Scientists can approximate the age of something old by (13) _______________." → "radiometric dating"

"By inspecting the fossils of organisms, scientists predict they will find a(n) (14) _______________." → "transitional fossil" (since they look for intermediates)

"Organisms across the Earth used to live on one super continent but became separated by (15) _______________." → "plate tectonics"

So for fill-in-the-blank:
10. DNA sequence
11. amino acid sequence
12. vestigial structure
13. radiometric dating
14. transitional fossil
15. plate tectonics

Now, going back to Part 2, since "transitional fossil" is used in 14, and diagram c is a fossil skeleton, it should be matched to 8.

Similarly, "vestigial structure" is in 12, so for question 6, we need to match it to a diagram.

Which diagram best represents vestigial structure? None perfectly, but perhaps diagram d is intended to show how some structures became vestigial over time? Or maybe in diagram b, if there's a reduced part.

Upon re-examining typical diagrams:

In many worksheets, the diagram with multiple limbs (diagram b) is for homologous structures, and the embryo diagram (a) for embryology, fossil (c) for transitional, and for vestigial, sometimes a separate diagram is given, but here it's not.

Perhaps diagram d is for vestigial? Let's see: Coelacanth fin — in modern times, coelacanths don't use their fins for walking, so the limb-like bones might be vestigial for terrestrial locomotion. That could be a stretch, but possible.

To resolve this, I'll use the following standard matching found in similar worksheets online:

- vestigial structure: not directly shown, but if forced, sometimes paired with evolutionary diagrams — however, in this case, let's assign based on elimination.

After careful thought, I believe the intended matches are:

6. vestigial structure → d (even though weak, perhaps because the fin is not fully functional for walking in modern context)
7. homologous structures → b
8. transitional fossil → c
9. embryology → a

Yes, that seems to be the convention in some curricula.

So:
6. d
7. b
8. c
9. a

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Now, compiling all answers:

Part 1:
1. e
2. c
3. b
4. a
5. d

Part 2:
6. d
7. b
8. c
9. a

Part 3:
10. DNA sequence
11. amino acid sequence
12. vestigial structure
13. radiometric dating
14. transitional fossil
15. plate tectonics

Let me double-check Part 2 Question 6: vestigial structure matched to d. Is there any justification? In diagram d, the Coelacanth's fin has bones homologous to tetrapod limbs, but in the coelacanth, these are not used for walking — so they could be considered vestigial for that function. It's a bit forced, but acceptable for middle school level.

Alternatively, some might argue that diagram b shows vestigial if there are reduced digits, but in standard interpretation, b is homologous.

I think it's safe to go with:

6. d
7. b
8. c
9. a

Final Answer:

1. e
2. c
3. b
4. a
5. d
6. d
7. b
8. c
9. a
10. DNA sequence
11. amino acid sequence
12. vestigial structure
13. radiometric dating
14. transitional fossil
15. plate tectonics