Grade 8 Animal Phyla and Symmetry Answers Worksheets 2024 - Free Printable

Let's solve this "Symmetry in Biology Practice Worksheet" step by step. I'll go through each question, explain the concepts, and provide the correct answers.

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1. a. What kind of symmetry does the warm, fuzzy animal to the right have?

The image on the right is a spider (likely a common spider with eight legs).

- Answer: Bilateral symmetry

> Explanation: Spiders are arachnids and belong to the phylum Arthropoda. They have bilateral symmetry — meaning they can be divided into two mirror-image halves along one plane (a sagittal plane), typically from head to tail.

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1. b. Draw the plane of symmetry through the animal.

- You should draw a vertical line down the center of the spider’s body, dividing it into left and right halves that are nearly identical.
- This line runs from the front (head) to the back (abdomen), passing through the middle of its body.

> ✔ Note: Since we can't draw here, just imagine or sketch a straight vertical line splitting the spider in half down the middle.

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2. Look at the figures below. Determine whether they have bilateral symmetry, radial symmetry, or are asymmetrical.

#### Figure a:
- Looks like a tortoise or turtle shell (or possibly a sea creature).
- It has a clear left-right division and appears symmetrical along a central axis.

> ✔ Answer: Bilateral symmetry

#### Figure b:
- A snowflake.
- Snowflakes have multiple lines of symmetry radiating from the center (usually 6-fold symmetry).

> ✔ Answer: Radial symmetry

#### Figure c:
- A horseshoe.
- It's curved but not symmetrical — no clear mirror image when split.

> ✔ Answer: Asymmetrical

> 🚫 Note: While it might look like it could have symmetry, a horseshoe is not symmetric due to its open shape and uneven ends.

#### Figure d:
- A stylized letter "A" with decorative swirls.
- It looks like it has a vertical line of symmetry (left and right sides match).

> ✔ Answer: Bilateral symmetry

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3. Fill in the table: Animal, Phylum, Symmetry

We’ll go row by row.

| Animal | Phylum | Symmetry |
|-------------|--------------------|--------------------|
| Snail | Mollusca | Bilateral |
| Fish | Chordata | Bilateral |
| Earthworm | Annelida | Bilateral |
| Anemone | Cnidaria | Radial |
| Frog | Chordata | Bilateral |
| Jellyfish | Cnidaria | Radial |
| Starfish | Echinodermata | Radial (adult) |
| Alligator | Chordata | Bilateral |
| Crayfish | Arthropoda | Bilateral |
| Ant | Arthropoda | Bilateral |
| Elephant | Chordata | Bilateral |
| Coral | Cnidaria | Radial |

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🔍 Detailed Explanations:

1. Snail – Mollusca, bilateral (though some mollusks like snails show torsion, they still have bilateral symmetry during development).
2. Fish – Chordata, bilateral; fish have a head-tail axis and paired fins.
3. Earthworm – Annelida, bilateral; segmented worms with distinct anterior-posterior axis.
4. Anemone – Cnidaria, radial; cylindrical body with tentacles arranged around mouth.
5. Frog – Chordata, bilateral; vertebrates are bilaterally symmetrical.
6. Jellyfish – Cnidaria, radial; umbrella-shaped with radial arrangement of tentacles.
7. Starfish – Echinodermata, radial (as adults); though larvae are bilateral, adult starfish have pentaradial symmetry (5-fold radial).
8. Alligator – Chordata, bilateral; reptile with a clearly defined head and tail.
9. Crayfish – Arthropoda, bilateral; crustaceans have segmented bodies and paired appendages.
10. Ant – Arthropoda, bilateral; insects have three body parts and bilateral symmetry.
11. Elephant – Chordata, bilateral; mammals are bilaterally symmetrical.
12. Coral – Cnidaria, radial; polyps have radial symmetry, often with six-fold or multiples thereof.

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✔ Final Answers Summary:

#### Question 1:
- a. Bilateral symmetry
- b. Draw a vertical line through the center of the spider.

#### Question 2:
- a. Bilateral
- b. Radial
- c. Asymmetrical
- d. Bilateral

#### Question 3: Table

| Animal | Phylum | Symmetry |
|-------------|--------------------|--------------------|
| Snail | Mollusca | Bilateral |
| Fish | Chordata | Bilateral |
| Earthworm | Annelida | Bilateral |
| Anemone | Cnidaria | Radial |
| Frog | Chordata | Bilateral |
| Jellyfish | Cnidaria | Radial |
| Starfish | Echinodermata | Radial |
| Alligator | Chordata | Bilateral |
| Crayfish | Arthropoda | Bilateral |
| Ant | Arthropoda | Bilateral |
| Elephant | Chordata | Bilateral |
| Coral | Cnidaria | Radial |

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This worksheet helps reinforce understanding of body plan symmetry in animals — a key concept in evolutionary biology and classification.

Let me know if you'd like a printable version or help drawing the symmetry planes!