• Identify the distinguishing characteristics of member of Phylum Cnidaria, including symmetry, number of embryonic tissue layers, unique structures, skeleton and polymorphism (polyp and medusa), place Cnidaria on a cladogram • Compare and contrast how a general polyp and a medusa feed • Describe why a nerve net was such a major evolutionary adaptation • Describe the characteristics of the four classes of Cnidarians • Label the following on a drawing: tentacles, mouth, anus, gastrovascular cavity, cnidocytes, nerve net • Describe the relationship of coral and zoxanthellae • Name some major threats to coral reefs and why they are so important to biodiversity • Know what coral bleaching is. • Know the effects of increased CO2 in the atmosphere and in the water upon corals. Solution 1.Characteristic of Phylum Cnidaria: Symmetry : radial or bi radial number of embryonic tissues: endoderm and ectoderm with body wall separated by mesoglea They have single opening into the body which act as mouth . There is tubular sessile polyp form and swimming medusa forms 2. Polyp have single opening surrounded by tentacles this opening act as both mouth and exceretion. Medusa form has mouth centrally located in a projection called manubrium on the ventral concave surface 4.Characteristic of four classes of cinidaria: 2. Scyphozoa: 3. Cubozoa: 4. Hydrozoa: 6. Most reef building corals contain photosynthetic algae called zooxanthellae that live in their tissue. The corals and algae have mutualistic relationship. Coral provide protection and compound they need for photosynthesis. 7.Major threat to coral reef is pollution , over fishing which causes ecological imbalance 8. When water is warmer coral will expel the algae [ zooxanthellae ] living in their tissue causing the coral to turn completely white this is called coral bleaching..

1. • Identify the distinguishing characteristics of member of Phylum Cnidaria, including symmetry,
number of embryonic tissue layers, unique structures, skeleton and polymorphism (polyp and
medusa), place Cnidaria on a cladogram
• Compare and contrast how a general polyp and a medusa feed
• Describe why a nerve net was such a major evolutionary adaptation
• Describe the characteristics of the four classes of Cnidarians
• Label the following on a drawing: tentacles, mouth, anus, gastrovascular cavity, cnidocytes,
nerve net
• Describe the relationship of coral and zoxanthellae
• Name some major threats to coral reefs and why they are so important to biodiversity
• Know what coral bleaching is.
• Know the effects of increased CO2 in the atmosphere and in the water upon corals.
Solution
1.Characteristic of Phylum Cnidaria:
Symmetry : radial or bi radial
number of embryonic tissues: endoderm and ectoderm with body wall separated by mesoglea
They have single opening into the body which act as mouth . There is tubular sessile polyp form
and swimming medusa forms
2. Polyp have single opening surrounded by tentacles this opening act as both mouth and
exceretion. Medusa form has mouth centrally located in a projection called manubrium on the
ventral concave surface
4.Characteristic of four classes of cinidaria:
2. Scyphozoa:
3. Cubozoa:
4. Hydrozoa:
6. Most reef building corals contain photosynthetic algae called zooxanthellae that live in their
tissue.
The corals and algae have mutualistic relationship.
Coral provide protection and compound they need for photosynthesis.
7.Major threat to coral reef is pollution , over fishing which causes ecological imbalance
8. When water is warmer coral will expel the algae [ zooxanthellae ] living in their tissue causing
the coral to turn completely white this is called coral bleaching.