Name: Date:

Phylum Cnidaria: Jellies, Anemones and Corals

Domain: Kingdom:

Learning Objectives: *Refer to Kingdom Animalia Unit Plan

Text page: 371 *This is required reading.

What are some common cnidarians?

Cnidarian Common Characteristics

Biology 11: Phylum Cnidaria Page 1

Despite the diversity in cnidarian form, all members of this phylum share the following characteristics:

a) Level of Organization

Cnidaria are one level more complex than Porifera as they have _________________________, making

them eumetazoans.

b) Body Plan

Cnidarians have a _________________________, body plan with _______________________________

_________________________ surrounding a central _________________________,

What are some functions for the gvc in Cnidarians?

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Instead of a mesoderm layer, cnidarians

have a _________________________,

a gel-like layer between the

_________________________ and

_________________________. It is

not considered a germ layer!

c) Symmetry

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What type of symmetry do cnidarians have? ___________________________

Polyp Medusa

Movement

Reproduction

Other

Compare and contrast the two different Cnidarian body forms below:

d) Tissues and Cell Specialization

Cnidarians have many cells and tissues specialized for particular functions.

i) All cnidarians have stinging cells called _________________________

that are used for __________________

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ii)

Epitheliomuscular Cells: ______________________________________________________________

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iii) Sensory Cells: ______________________________________________________________________

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iv) Interstitial Cells: ____________________________________________________________________

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v) Gland Cells: ________________________________________________________________________

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vi) Nutritive Muscular Cells: _____________________________________________________________

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Cnidarian Essential Functions

a) Digestion

Digestion occurs in the GVC,

where digestive enzymes

breakdown food particles into

small enough molecules to be

engulfed by or diffuse through

the cell membrane of nutritive

muscular cells.

ii) Cellular Respiration

Gases diffuse from high concentration from low concentrations (O2 into cells from H2O; CO2 from cells

into H2O).

iii) Reproduction

Some Cnidarians pass sequentially through a polyp and medusa stage in their life cycle, such as the

Obelia life cycle below.

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Why Do We Care about Cnidarians?

Conduct your own research to discover at least five ways that corals are important to their ecosystems and

the larger world

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Threats to Cnidarians

The Cnidarian currently experiencing the greatest threat to its existence is coral. Watch the video on

coral bleaching and complete the questions below.

What are corals?

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What is coral bleaching?

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There are three general methods for working to bring back damaged coral reefs:

1. Structural Restoration:

Construction of artificial reefs to

increase surface area available for coral

growth.

Required in areas where structural

integrity of ecosystem has been

compromised or lost due to disturbances

(dynamite fishing, landslides…).

2. Biological Restoration:

Increasing the number of corals living in a suitable habitat by

collecting/rehabilitating naturally broken coral fragments,

culturing coral larvae and transplanting living coral colonies.

Necessary in areas where coral die off has occurred (bleaching,

disease, predation, ect).

3. Physical Restoration:

Improve the health and growth of reefs by adding coral

nurseries, changing water chemistry through electrolysis….

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