unit 5: marine phyla of life
1. describe in a sentence or two what happened during the cambrian period.

2. review and summarize coral reef formation and coral reproduction strategies.

3. describe the difference between a polyp and medusa. which body form do corals have their entire lives?

4. what are corals, and how are they classified biologically?

5. what is the difference between hard corals and soft corals?

Question

unit 5: marine phyla of life
1. describe in a sentence or two what happened during the cambrian period.

2. review and summarize coral reef formation and coral reproduction strategies.

3. describe the difference between a polyp and medusa. which body form do corals have their entire lives?

4. what are corals, and how are they classified biologically?

5. what is the difference between hard corals and soft corals?

Accepted Answer

### Question 1
# Brief Explanations:
The Cambrian Period (541–485.4 million years ago) saw the Cambrian Explosion, a rapid diversification of life with most major animal phyla appearing, many marine organisms (like trilobites, arthropods, and early chordates) evolving, and complex ecosystems forming in oceans.
# Answer:
During the Cambrian Period, a massive diversification of life (the Cambrian Explosion) occurred, with most major animal phyla appearing, diverse marine species evolving, and complex ocean ecosystems developing.

### Question 2
# Brief Explanations:
- **Coral Reef Formation**: Corals (colonial polyps) secrete calcium carbonate skeletons. Over generations, these skeletons accumulate, forming reefs. Symbiotic zooxanthellae (algae) live in coral tissues, providing nutrients (via photosynthesis) and aiding skeleton building. Reefs grow in warm, clear, shallow tropical waters with sunlight (for zooxanthellae) and stable salinity/temperature.
- **Coral Reproduction Strategies**:
  - **Sexual**: Broadcast spawning (corals release eggs/sperm into water; external fertilization) or brooding (sperm enter polyps, fertilize eggs internally, larvae released). Timed with lunar cycles/tides.
  - **Asexual**: Budding (new polyps grow from parent) or fragmentation (broken coral pieces reattach/grow, forming new colonies).
# Answer:
- **Coral Reef Formation**: Corals (colonial polyps) secrete calcium carbonate skeletons; over time, these accumulate, forming reefs. Symbiotic zooxanthellae in coral tissues provide nutrients (via photosynthesis) and support skeleton growth. Reefs thrive in warm, clear, shallow tropical waters (sunlight for zooxanthellae, stable conditions).
- **Coral Reproduction**:
  - *Sexual*: Broadcast spawning (eggs/sperm released into water for external fertilization) or brooding (internal fertilization, larvae released). Timed with lunar cycles.
  - *Asexual*: Budding (new polyps from parent) or fragmentation (broken coral regenerates into new colonies).

### Question 3
# Brief Explanations:
- **Polyp vs. Medusa (Cnidarian Body Forms)**:
  - *Polyp*: Sessile (attached to a surface), cylindrical body, mouth/ tentacles facing upward (e.g., coral polyps, sea anemones).
  - *Medusa*: Free - swimming, bell - shaped body, mouth/ tentacles facing downward (e.g., jellyfish).
- **Corals’ Body Form**: Corals (Cnidarians, class Anthozoa) retain the polyp body form throughout their entire lives (they are sessile, colonial polyps).
# Answer:
- **Polyp vs. Medusa**: Polyps are sessile, cylindrical, with mouth/tentacles upward; medusae are free - swimming, bell - shaped, with mouth/tentacles downward.
- Corals have the polyp body form their entire lives.

### Question 4
# Brief Explanations:
- **What are Corals?** Corals are marine invertebrates (phylum Cnidaria, class Anthozoa, mostly colonial) that secrete calcium carbonate skeletons. Many host symbiotic zooxanthellae (algae) for nutrients/energy. They form reefs, provide marine habitats, and are vital to ocean ecosystems.
- **Biological Classification**:
  - Kingdom: Animalia (multicellular, heterotrophic, lack cell walls).
  - Phylum: Cnidaria (have cnidocytes - stinging cells, radial symmetry, two body forms: polyp/medusa).
  - Class: Anthozoa (exclusively polyp form, colonial/ solitary, secrete skeletons; includes hard corals, soft corals, sea anemones).
# Answer:
- **Corals**: Marine invertebrates (Cnidaria, Anthozoa, often colonial) that secrete calcium carbonate skeletons. Most host symbiotic zooxanthellae, forming reefs and supporting marine ecosystems.
- **Biological Classification**: Kingdom Animalia → Phylum Cnidaria (cnidocytes, radial symmetry) → Class Anthozoa (polyp - only form, colonial/solitary, skeleton - secreting).

### Question 5
# Brief Explanations:
- **Hard Corals (Scleractinian Corals)**: Secrete rigid calcium carbonate skeletons (stony corals), form the structural base of reefs. Colonial (e.g., staghorn, brain coral) or solitary. Depend on zooxanthellae (need sunlight, shallow water). Skeletons are permanent, visible, and reef - building.
- **Soft Corals**: Lack rigid calcium carbonate skeletons (have flexible, protein - based structures or small calcareous spicules). Often colonial (e.g., sea fans, leather corals). May host zooxanthellae but can also filter - feed. Thrive in varied depths, less reef - building but add biodiversity to reef ecosystems.
# Answer:
- **Hard Corals**: Secrete rigid calcium carbonate skeletons (stony), form reef structures, colonial/solitary, depend on zooxanthellae (shallow, sunny waters).
- **Soft Corals**: Lack rigid skeletons (flexible/with spicules), colonial (e.g., sea fans), filter - feed/host zooxanthellae, thrive in varied depths, less reef - building.

Sovi.AI - AI Math Tutor

QUESTION IMAGE

Question

Explanation:

Question 1

Answer:

Question 2