SCED 313
Mini-Unit Planning and Lesson Preparation
Porifera and Cnidaria:
An Introduction to Animals
Matthew Last: Lessons #1, #2
Sean Juteau #3, #4
Overview Statement
In this mini unit plan we are looking at Porifera and Cnidaria. This unit introduces
students into the world of animals. They would have just finished there unit on the higher
dryer plants. Students are now going to look at the lowest form of animals and get the basic
definition of what being an animal is. In the next section students will look at sponges in
more detail learning about there body form and how they feed. This is aligned with the
Biology 11 IRP: Examine members of the Phylum Porifera and Phylum Cnidaria and
describe characteristics that unify each (pg 30). This is a good starting place for students to
understand the difference between plants and animals using the most simple form of an
animal. By using Venn diagrams the students will be able to grasp the idea and be able to
compare and contrast sponges in a more creative way then just tables and charts, as
organisms do not always fit nicely into catagories. By analyzing what characteristics sponges
have a student will be able to recognize that they belong with animals. The assessment used
is to promote students organizational skills and the ability to classify organisms based on
certain criteria. It is good for students to see that science organizes organism based on loose
criteria that are as cut and dry as they have may learned before. The closure slip allows the
teacher to gauge how the class went and how the next class should be run.
The next lesson plan deals with investigating the sponge. Having covered how things
are classified and what makes sponges animals, students are ready to delve more deeply into
what sponges are. Instead of me writing notes I will have the students come up with their
own notes and presentations. By doing this, the students are interacting with their learning
and are no longer just memorizing the facts. And by having the class evaluate and take notes
on each presentation students are held accountable for the information that is present in
each groups presentation. This activity takes the basic knowledge and comprehension skills
and forces them to think about things in a different way, pushing their understanding into a
higher level of Bloom’s. Students also will be able to have fun with this activity and by
letting them create a translation activity of their own, students will have a deeper
understanding of the material. The PLO’s covered in this section is: Explain the process of
filter feeding in a sponge. This PLO is shallow and barely covers the interesting world of
sponges and by fleshing out the topic students will have a better overall understanding of
sponges.
In the introduction to Cnidaria allows students hands on work with something most
will be comfortable using. Now the students learning is self guided. By using this online
resource the students study will be self-paced and students will be able to go through the
sections in the order they see fit. By using an interactive web page, such as this, students will
be able to go through a large amount of information in a short amount of time. Students
will be engaged in learning via a multimedia approach that couldn’t be done in a classic
lecture style. This lesson covers the following PLO’s: Compare and contrast polyp and
medusa with respect to structure, general function, and motility; and Suggest the
advantages of a motile form in the life cycle of a cnidarian. The assessment of the note
package contains a variety level of Bloom’s as students are asked not only to recall but to
evaluate and explain adaptations of Cnidaria and why they may have arose. The sheets
provided are also a good way to set students up for the upcoming unit test.
The final lesson covers the PLO’s: Demonstrate knowledge of the ecological roles of
sponges and cnidarians; and Explain the evolutionary significance of multicellular
(cnidarian) versus colonial (poriferan) life forms. This now takes what they have learned
about these organisms and throws them directly into the real world. The students now can
look at the specific adapatatation of each organism and can look at how the may have
evolved in an ecological as well as an individual sense. By using the hands, of the assembly
line demonstration, students will be able to understand how cell specialization relates to
multicellular organisms. This Higher level of Bloom’s is synthesis as the students must
predict and draw conclusions about which team will win the race based on what adaptations
they have. Students must then transfer this idea to how the adaptations in these simple
animals have made them successful.
Evaluation has been setup to cover the PLO’s in a broad sense but have been geared
directly towards the SWBATS we listed in each lesson plan. The variety of questions probes
both knowledge of information and the ability of students to reason by using skills they
acquired during this unit. By keeping a parallel set up with the Venn diagram introduced in
the first lesson, the students will be able to directly tackle the PLO, Examine members of the
Phylum Porifera and Phylum Cnidaria and describe characteristics that unify each, and be
able to apply their knowledge at a higher level of thinking. The use of multiple-choice
question allows us to cover a large range of materials of what was covered in a short amount
of time. Using longer answer questions where the student has to draw diagrams also jumps
into the higher level’s of Bloom’s, as the students must reconstruct the knowledge they have
in their head and put it on paper in an artistic way. This will take the knowledge in their
minds and make them connect it to the real world in ways multiple-choice questions cannot
do. This test is set up to cover a broad range of topics, but allows us to focus in on certain
SWBATS that we feel are key to the understanding of this unit, and that will allow students
to use skills they acquired during the unit, and hopefully will be able to use to learn about
other units.
Lesson Plan #1
Topic
Intro to Animals: Cnidarians and Porifera
Rationale
This lessons goal is to help students get their first glimpse into these groups
of animals. What makes up animals and why Porifera and Cnidaria are animals? Students
will be working in groups of 3 or 4 creating different Venn diagrams of these 2 groups to
help them understand why these groups are animals and what makes them unique. This
activity challenges higher levels of Bloom by having the students Analyze what makes a plant
different from and animal.
PLO’s:
-Examine members of the Phylum Porifera and Phylum Cnidaria and describe
characteristics that unify each
Student Learning Objectives
SWBAT:
-describe the features that make Porifera and Cnidaria animals
-compare plants and animals using examples
-be able to distinguish if an organism is a plant or animal based on its
characteristics
-be able to draw and explain a Venn diagram
-question why science uses distinct groupings to explain ambiguous concepts
Materials
-synthetic sponge
-Samples of real sponges
-Sample of a plant
-OH provided
-large sheets of paper 6, (24 students 6 groups of 4)
Anticipatory Set
Call class’s attention to the front of the room. Hold up a manufactured sponge and
ask the class what it is, or put up trademarked picture of a still to be unnamed FAMOUS
SPONGE.. Ask students if they know why we call them sponges. When student suggests
we used to uses Porifera as sponges continue on discussion. Ask students what a sponge is
and write it on the board. There may be discussion on what a sponge really is. If the
question comes up ask if sponges should be called plants, animals, or something else?
Activities
1) Have the students break into groups of 4 and have them list, on a sheet of paper,
their idea of what makes an animal and what makes a plant. Give students enough time to
write and gather their ideas, 5 to 10 minutes should be more than enough, if enough start to
get off task call class back. Explain to the student what a Venn diagram is by drawing two
large overlapping circles on the board. Write on one side PLANT and on the other side
ANIMAL. Ask each group to copy down the diagram on the sheet and have them place the
characteristics of a sponge that fit into each category.
Walk around classroom pointing out ideas and encourage students to put whatever
they think down on the paper. After 10 minutes have, the students raise their hands and
suggest where you would put each part of the sponge in the Venn diagram.
2) Now that the students have constructed where they think the sponge fits bring up
the overhead on what makes up an animal. This will allow the students the ability to
see where sponges fit into the animal kingdom and WHY they belong there and not
with plants.
Continue through the sheet and describe each word associated with what being an
animal is. Multicellular can include plants, and is another step above colonial
organisms. This means that colonies have no organization while multicellular does,
this line is blurry at Porifera, as they seem to straddle the line. Science likes to make
cut and dry examples, but real life is never so simple. Animals also lack a cell wall.
Last the most important point that animals are heterotrophs and must eat to survive
unlike plants, where they just need light to make food.
Bad Joke: So do we, ever try to get food out of the fridge when the lights are out?
Formative Assessment:
Students will be assessed informally during this setting based on group work and
the completion and explanation of their Venn Diagrams. Students will should be
checked for the proper placement of the components of being a sponge. The
assessment will be done by having the student groups hand in their Venn Diagrams
and they will be returned the next day.
Rubric
Unicellular Colonial Multicellular
Students’ Venn diagram is Some to most of the points Venn Diagram is neat and
incomplete or has are correct in their placement easily understood. All to
information all over the page in the Venn Diagram. most of the items are placed
without the use of the Students only had points in proper circle, students
circles. Most or all of the covered in class in the Venn include other items not
information is in the wrong diagram. covered in the lecture.
circle and the student has not
written down
Closure:
Students will now be allowed to edit their Venn diagram to fit to the model they have
formed. Students will be asked to write exit slips, and must write down a question they had
about the days lecture OR something interesting they learned. This will allow the teacher to
gage individual understanding without having the students feel judged by their peers. Ask
students to read about Porifera in their texts and make notes, and tell them to be prepared to
be ready for the activity on Porifera for the next day. If this lesson goes quickly continue on
to next activity, as the more time the students have the better
OH:
Animals (Kingdom Animalia)
-multicellular/cells with specialized
structure
-lack cell wall
-are motile in one stage of life
-are HETERTROPHS
Barrel Sponge
Lesson Plan #2(approximately 2 days)
Topic
Porifera
Rationale
Students will learn about the basics of Porifera by taking the notes that they have
studied about and then take that information and present it to the class in a different form,
via a translation activity. Students will be encouraged to understand sponges by show their
knowledge about them via different a different medium. Students will be involved in higher
levels of Bloom’s as they must interpret and synthesize and present what they have learned
about sponges in a different way.
PLO’s:
-Explain the process of filter feeding in a sponge
-Examine members of the phylum Porifera and Phylum Cnidaria and describe
characteristics that unify each
Student Learning Objectives
SWBAT:
-Describe and draw the water flow through a sponge
-Explain how sponges reproduce
-explain how sponges are useful to humans
-understand diversity and beauty of sponges
-explain the different classes of sponges
-list the characteristics that unify sponges
-explain the disadvantages and advantages of being sessile
Materials
-Handouts on group presentation
-any Spongebob Squarepants clip
http://www.nick.com/all_nick/tv_supersites/video_vault.jhtml?show_id=spo&clip=0
-laptop and projector /OH’s in this case
-see teacher handout for links and references
Anticipatory Set:
Show students slide show of sponges, to highlight their diversity and beauty. This
might get kids interested in seeing biology outside of the classroom. There may be students
who have snorkelled or scuba dove before. Have the students pick out the sponges in the
picture and explain why they are sponges compared to the other life forms around. This is
good review of last class. Also show any quick clip of Spongbob Squarepants, and then ask
students what is wrong with this depiction of sponges.
Activity:
After showing the clip start, the class off with what it is to be a sponge. Students will be
broken into different groups and assigned one of 6 topics about sponges. Students will be in
groups of 4 students and their job is to teach the class something about sponges in any way
they see fit. The following topics are to be handed out: sexual reproduction, asexual
reproduction, feeding, body structure, habitat, sponge diversity. This can be done via a
random draw from a hat, with each topic on a piece of paper.
Each group then must come up with any way they can think of to present this topic to the
class anything from a video to a poem to a interpretive dance is acceptable. The students
may choose whatever medium they wish to present, but the presentation is limited to 10
minutes. They may use whatever they want as long as they can present the facts to the class
and the class can somehow make notes out of their presentation, or are provided a
facilitation to explain what they were doing.
This class time will be spent with the groups decided what they are going to do and how they
are going to present it. If time permits the students may begin to do their information
research during this class period, and should be ready to present next class (this will be
assigned on a Friday if possible, depending on schedule you may need to give one more class
research time to complete it).
Closure:
By the end of the class, the students should have a grasp on what they are doing. Have the
students hand in 1 sheet per group their basic idea and plans of what they are going to do.
The next class will be used for preparation and students are reminded to bring any resources
they need to the next class. Any final questions before they go off to finish their short
presentations. This presentation can be done next class. Before the presentation the
students will be handed a sheet of the criteria of the groups so they can try and answer the
questions that the presentation is trying to answer.
Hand Outs:
Sexual reproduction
Please cover the following idea in your translation activity.
Reproductive cells of sponges
Location of these cells in sponge
Advantages and Disadvantages of this mode of reproduction
Asexual reproduction
Please cover the following idea in your translation activity.
How does a sponge reproduce asexually
Are there special cells for this function or not?
Advantages and Disadvantages of this mode of reproduction
Feeding,
Please cover the following idea in your translation activity.
How do sponges attain nutrients?
What cells are involved in nutrient gathering and distribution.
Where do the waste products go?
Body structure,
Please cover the following idea in your translation activity.
How is a sponge set up?
What are the major parts of the sponge? Cavities, Passages (etc)
What is the size range and colours seen in sponges?
Habitat,
Please cover the following idea in your translation activity.
Where can I find sponges?
What role do they play in their environment?
Are sponges preyed upon and why?
Sponge of the World
Please cover the following idea in your translation activity.
What are the different classes of sponges?
How do you tell them apart?
What is the diversity of sponges?
Rubric for marking (Formative mark)
Luffa Kitchen Sponge Spongebob
(not a sponge) (you did the job) Squarepants
(0-2) (3-6) (super job)
(7-10)
Material Covered Shallow in depth and Covered questions Gone beyond the
X2 didn’t cover listed but nothing questions asked and
questions listed. Or beyond that. Most beyond the text
information is wrong information
Presentation Boring, misguided, Well prepared, easy Totally original idea.
X1 hard to follow, not to understand, well Lots of outside work
well prepared organized put into, plus ideas
from last column
Group Work Apparent no one put Well distributed Everyone did equal
X 0.5 much effort into apparent that work share of work
project or one was shared
person did it all
Total out of 35. Group work will be marked based on feedback from others in group and a
self evaluation of your contributions. Students will state explicitly what they did in this
project. From the what the group hands in a package of notes will be made for the students
in the class and based on these presentations questions for the final will be made.
See next page for an example of the STUDENT HAND OUT
The group evaluation is very subjective and only can be done effectively if you know your
students well. Part of the reason why the mark is worth only 5 out of 35 marks as it can be
hard to judge group work.
Sexual reproduction
Students will present their topic and then hand in a summary of what they did to the teacher.
For example if you did a skit, a copy of the script with important information underlined or
highlighted, should be passed in and be properly cited. On a separate sheet of paper, please
write down your contribution to the group. In addition, find the group/self evaluation
forms. Please save these sheets for until your presentations are complete.
Please cover the following idea in your translation activity.
Reproductive cells of sponges
Location of these cells in sponge
Advantages and Disadvantages of this mode of reproduction
USE THE SPACE BELOW TO BRAINSTORM YOU IDEAS FOR YOUR ACTIVITY
Suggestions for activity: Game show, skit, interpretive dance, drama, board game, power
point presentation, poem, advertisement, newspaper story, reality TV, sitcom, talk show.
Please don’t limit yourself to these choices, and feel free to ask me about other ideas.
Group Evaluation Sheet
This sheet will be used to help determine your mark for group presentation
Your Role in the Presentation:
Self evaluation: Scale of 1-10 and why. Did you feel like you contributed and were listened
to?
Group evaluation, did the group come together or not? Scale of 1-10. Please explain your
reasoning.
Teacher information:
Notes that may assist in marking the presentations
Key features of Porifera
Multicellular, body a loose aggregation of cells.
Body with pores, canals and chambers that serve for passage of water. Ostia is in hole
while ostium is outflow hole.
All aquatic, mostly marine.
Symmetry radial or none.
Epidermis of flat pinocytes; interior surfaces lined with choanocytes that create water
currents
Skeletal structure of collagen and calcareous or siliceous spicules.
No organs or true tissues; digestion intracellular, excretion and respiration by diffusion.
All adults sessile and attached to substratum.
Asexual reproduction by buds and gemmules and sexual reproduction by eggs and
sperm; free-swimming ciliated larvae.
4 classes: Calcarea calcium carbonate skeleton; Hexactinelle 6 rayed silicate spicules;
Demospongiae 1 to 4 rayed spicules, or spogin fibres; Sclerospongiae aragonite-silica is
main skeletal component, known as coralline sponges;
approximately 5000 species
Check text for additional help
Filter feeders
Ameboid cells used to transport wastes and nutrients around
Wastes diffused into water passage
collar cells generate current through the passages
Also check out the following web pages
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102
%20lectures/Animal%20Diversity/Lower%20Invertebrates/sponges.htm
http://www.mote.org/SPONGE.HTM
http://www-biol.paisley.ac.uk/courses/Tatner/biomedia/units/pori1.htm
http://www.oceanicresearch.org/sponges.html
Along with text from class
Lesson Plan #3
Topic
Cnidaria
Rationale
This lesson design is to help student understand the basic morphology, habitat and
lifestyle of Cnidarians. Students will be working in pairs and discussing answers to reinforce
them. The students will be working with Cyber-Ed on line. The worksheet will cover
various levels of learning.
PLO’s:
• Compare and contrast polyp and medusa with respect to structure, general
function, and motility
• Suggest the advantages of a motile form in the life cycle of a cnidarian
Student Learning Objectives
By the end period, students should be able to:
• Describe the characteristics that unite cnidarians
• Describe the two (medusa and polyp) basic body types of cnidarians
• Diagram the basic body plan of a medusa and a polyp
• Describe cnidocytes and their function
• Suggest the advantages of a motile form in the life cycle of a cnidarian
• Provide an example of each class of Cnidarian
Materials
• Worksheet
• Cyber-Ed software
• Computers
• Login = Class name
• Password = trial
Anticipatory Set
Question on the board “Does anyone know an animal whose mouth is the same as it’s
anus?” (or some such variation of this question).
Activities
The students will complete the worksheet attached will using the Cyber-Ed on-line software.
Closure
Before students leave class they must hand in a paper with two statements on it:
1) What is one topic that was very clear from this lesson
2) What is one topic they are still confused by or a question they have about something
from class today.
Cnidarian Worksheet
Go to the following website and login using the following:
Password: Class name
Login: Trial
Website: http://www.cyberedonline.com/programs/biology/default.asp
Follow the instructions on this worksheet to answer all of the questions. Check with your
partner to make sure you have fully answered all of the questions.
Part 1. Use slides 1-23 in the presentation to fill in the blanks.
Scientists have discovered over ___9000___ species of Cnidarians. Cnidarians are
animals because they have a __membrane bound_ nucleus, their cells do not have _walls__,
and they eat __other organisms__. Cnidarians have __radial__ symmetry. Cniadrians have
two main body types the __medusoid__ and polypoid form. Another similarity among
cnidarians is __tentacles___ around the mouth. Embedded in the epidermis of all cnidarians
are __cnidocyte__ cells. The cnidocytes can be stimulated by either touch or chemical
stimulation. Another similarity that unites Cnidarians is their __sac-like___body.
Part 2. Classes
Use slides # 1 and lesson # 24, 41, 53 to name all 4 classes and provide 1 or 2 examples of
each class of Cnidarian. Also try to find out what each class means (you may have to use
your text for this one).
Name: Example
Name: Example
Name: Example
Name: Example
Part 3. Body Plans
Use Slide # 12, 54 and lessons #3, 6 & 8 to create a diagram of both the medusoid and
polypoid basic structures. (use extra sheet of paper provided for diagrams). Make sure to
label all of the following where appropriate:
• gastrovascular cavity • mouth • mesoglea
• tentacles • oral arm • acontia threads
• gastroderm • epidermis
Part 4. Cnidocytes
Use lesson #2 and slide #’s 15-18 to help you answer the following questions and diagram
and label a cnidocyte. Make sure to include:
• Filament •barb • operculum • nematocyst
• cnidocil
Questions:
1) What are the two types of stimuli that will cause a cnidocyte to spring?
2) The filament found in cnidocytes can have multiple functions. What are two
possible adaptations that can be found on cnidocytes?
3) What are some possible evolutionary benefits to having cnidocytes?
Part 5. Motility
Use lesson # 4 and slide # 34 & 47 to match the following animals with their form of
motility.
Possible choices: A. Sea Anenome C. Jellyfish
B. Hydras D. Corals
____ Animals will hitch a ride along the back of other sea creatures, like crustaceans
____ Produce a gas bubble that helps float the animal to the surface
____ Animal will curl up and roll along with the ocean currents
____ Moves by swimming in a pulsating manner
____ Bend over and attach the tentacles and pull basal disc forward
____ Perform acrobatic flip flops
____ Animal is sessile (doesn’t move) in it’s adult form
____ Epidermal cells secrete mucus substance on their pedal disc that the animal will
slowly glide along
____ Slowly glide along basal disc
____ Animal will bend and move in a spastic swimming motion
Lesson Plan #4
Topic
Ecological and Evolutionary Significance of Cnidaria & Porifera
Rationale statement
The object of this lesson is to get the students to ask why poriferans and cnidarians are
important to our ecosystems and provide a bit of a summary for these two topics. The
students will also be exploring why it is significant to have a multicellular organism.
PLO’s
• Demonstrate knowledge of the ecological roles of sponges and cnidarians
• Explain the evolutionary significance of multicellular (cnidarian) versus colonial
(poriferan) life forms
Student Learning Objectives
By the end of the lesson, students should be able to:
• Explain the difference between colonial and multicellular & provide examples of each
• Explain possible reasons for the evolution of multicellularity
• Describe the role of cnidarians and poriferans in the food web
Materials
• Sets of balls of various sizes (need to know diameters)
• 50 potatoes, 4 peelers, 4 knifes, two pots, 4 cutting boards and at least two sinks or buckets
• Overheads
Anticipatory Set
Show clip from beginning of Finding Nemo that depicts the relationship between
Clown fish and sea anemones. Movies are always a good way to gather students attention
and it will provide a good visual lead in to the ecological role of cnidarians.
Activities
1) Economy of size activity
Aim of the activity is to show that large numbers smaller of cells are more
efficient than larger cells. This is a concept they have gone over before. Have a
bunch of balls with known radius/diameter. Figure out the surface area to volume
ratio of each and discuss which would be better for a cell. Keep in mind dilution
speed and membrane transport. By end of activity students should be aware that
smaller cells are more efficient and single cells eventually become ineffective.
Multicellular organisms needed if the organism is going to be significant size.
2) Assembly line
Have six students volunteer to do an activity in front of class. Three students will
all wash potatoes, then peel them, then cut them in half before sticking them in a
bucket of salt water. The other three students will have one washer, one peeler and
one cutter. See which group can do 25 potatoes first. Ask class which group will be
faster. Ask whether there is a difference in skills needed among the group or
equipment. Link activity to specialization of cells and multicellularity.
3) Food web
Have students draw a food web on the board connecting sponges, cnidarians and
other animals to get an appreciation for how they fit into the ecosystems. Be sure to
include photosynthetic algae and humans in the web.
Closure
Before leaving class each student must write down 1 question that the think would be
appropriate to have one their unit test. It could be anything from the entire unit.
Overhead
Evolutionary significance
Cell size:
• Smaller cells more efficient than large ones
• Single cell organisms can only get to a certain size before they need to be multicellular
Multicellularity:
• Allows specialization of tissues
• More complex animals
Sponges:
• First animals
• Specialized cell types
Cnidarians:
• Nerve net
• multicellular
• colonial
• specialization of cells
• first animal to have tissue level organization
Ecological roles
Sponges:
• filter feeders
• food for snails, starfish and some fish - brings trophic level up (algae > sponges > fish)
• break down shells and corals by boring holes in them
• used as sponges in baths, etc
• chemicals from them have been isolated for use in antibiotics, (leukemia, arthritis)
Cnidarians:
• Certain shrimp, fish and other animals live among tentacles of sea anemones (eg, clown
fish - finding nemo)
• Corals provide habitat for many organisms (eg, clams, which is where we get pearls, fish)
• Corals provide wave break for land, without coral many shores would be washed out
• Fossil reefs can be used to show oil deposit location
• Coral can filter drinking water
• Cnidarians chemicals used in cancer research and nerve-cell research
Assessment for Unit
Multiple Choice: Choose the answer that best fits the question.
1) What does Porifera mean?
a. Hole Bearing c. Filter Feeder
b. Water pours through them d) None of the Above
2) How many species of sponges are there
a. 1000 c. 900
b. 2000 d 5000
3) What is the difference between a Porifera and cnidarian
a. Size c. Sexual reproduction
b. Presence of Tissue d. Radial Symmetry
4) If you were to chop up a Porifera would it survive and re-grow?
a. Yes b. No
5) Which is not a Porifera
a. Luffa c. Calcarea
b. Demospongia d. All of the above
6) What animal is capable of producing a gas bubble that helps float the animal to the
surface?
A. Sea Anenome C. Jellyfish
B. Hydras D. Corals
7) Which is not a characteristic found in animals?
A. membrane bound nucleus C. cell walls
B. hetertrophs D. RNA
8) What could cause a cnidocyte to spring?
A. chemicals C. motion
B. wave action D. none of the above
9) Animal can curl up and roll across the ocean floor with the currents.
A. Sea Anenome C. Jellyfish
B. Hydras D. Corals
10) Which animal can provide a living space for certain species of fish?
A. Corals C. Sea Anenome
B. Poriferans D. All of the above
Short Answer
1) What is the function of the flagellated cells (chaoanocytes) in sponges (3 marks)
Move water in and out (2), catching particles of food (1)
2) Trace the path of water from when the food particle enters the Porifera to when the
waste products exit the sponge. (4 marks).
Ostia, Cannals, Collar Cells, Cannals, Ostium
3) What cells bring the food from the flagellated cells to the rest of the organism?
Amoeboid cells.
4) What are the two basic body types for Cnidarians (2 marks)
• Medusa and Polyp
5) What type of symmetry is found is cnidarians (1 mark)?
• Radial
6) Name at least two things that unites cnidarians (2 marks)
• Cnidocytes, sac like body, tentacles
Long Answer
1) Using a Venn diagram compare and contrast Porifera and Cnidaria (9 Marks)
One point per answer, max 3 per area, total 9 marks.
2) Explain how Porifera Reproduce. (4 marks
-Since they are sessile they need to release sperm and eggs, the zygote
is the dispersal phase. (2marks)
-If they bud or fragment, those parts may grow into new organisms(2
marks)
3) Describe function and structure of a cnidocyte (5 marks). You will need to diagram.
• Answers will vary, must include 5 of : filament, barb, operculum, nematocyst,
cnidocil, either sticky substance or chemical poison
• One mark if diagram looks correct
4) Why do you think multicellurality evolved (4 marks)?
• Single cell organisms can only get to a certain size
• Allows specialization of tissues
• More complex animals
• Evolution tends towards more complex creatures