Easier to download versions of assignments

Jethro

Iago

Interesting Science Post

If you want to read about parasites that control fish brains - forcing the fish to swim in a way that makes it easy for birds to catch and eat them - look here.

Some websites for hydra and daphnia

Hydra:

http://www.virtuallaboratory.net/Biofundamentals/lectureNotes/Topic6-1_Communities.htm (look towards the bottom of the page)

http://cas.bellarmine.edu/tietjen/images/cnidarians.htm

and Wikipedia (as of this moment) is good on hydra:

http://en.wikipedia.org/wiki/Hydra_(genus)

Daphnia:

Wikipedia is good again:

http://en.wikipedia.org/wiki/Daphnia

Another daphnia page:

http://lhsfoss.org/fossweb/teachers/materials/plantanimal/daphnia.html

Last week's notes on skeleton types, available here: http://docs.google.com/Doc?id=ddsm58ms_16hddw97fb

Notes from today available at:http://docs.google.com/Presentation?id=ddsm58ms_10cvfbhhfq

W16 Syllabus

Block III, W16 Science Syllabus

Note: The dates for this week's assignments are not set - we will have to arrange the work schedule based on when we receive the materials for the hydra-daphnia lab.

In-Class Work	Homework
"Iago" - Hydra-daphnia lab report Part One: Pre-lab questions. These will not be graded, but must be complete before you may begin the lab!
Part Two: Lab participation - your participation in the lab - including appropriate use of equipment, being on-task, listening to directions and (last but not least) cleaning up after the lab, will significantly affect your participation grade!	Part Three: Lab Report - notes and answers to lab questions must be typed in full sentences. Pictures from your notes can be attached separately. This will be due the day after completion of the lab.
	"Jethro" - human and hydra digestion comparison.

Iago - Daphnia Hydra

“Iago”
- Daphnia and Hydra Lab

Prelab
questions:

Use
classroom researches to answer these questions on a separate sheet of
paper. Prelab questions must be complete before you can begin the
lab!

What
is a Daphnia? What phylum does it belong to? What do they eat?

Sketch
a Daphnia below, labeling anterior and posterior ends.

What
phylum do Hydra belong to? What do hydras eat?

What
are nematocysts and how do hydras use them?

Sketch
a hydra below, and label the oral and aboral ends. Show where the
mouth of the hydra is.

What
do you predict will happen when a hydra and a daphnia are introduced
into the same dish? Explain your reasoning.

Feeding
the Hydra!

Answer
all questions and make all drawings on your own paper - you will be
using these notes and sketches for you typed lab report.

In
this lab, you’ll observe the feeding behavior of the brown
hydra. The brown hydra is a predator; it uses it tentacles, lined
with stinging cells called nematocysts,
to capture prey. In this case, we’ll be feeding them tiny
aquatic crustaceans called daphnia.

Procedure

1. Use
   a pipette to carefully take a hydra from the shipping container and
   place it on a microscope slide. (You may need to use the pipette to
   shoot a gentle stream of water at the hydra and then suck it into
   the pipette while it’s floating loose.)

   
   

2. Let
   the hydra settle down and observe it for a few minutes under the
   microscope. (Do not
   use the highest power!) Use your notebook to
   record careful, detailed notes describing
   the behavior of the hydra. (What parts of it are moving? How are
   they moving? How fast or slow?

   
   

3. Draw
   a picture of the hydra.
   The hydra sits on a strong muscle called the basal disk. At the
   other end, the tentacles surround the hydra’s mouth. Label the
   basal disk, tentacles. Also label the oral and aboral ends.

   
   

4. Get
   a separate dish and use a pipette to carefully take a daphnia from
   the shipping container and place it on a microscope slide. Try to
   get the smallest daphnia you can.

   
   

5. Observe
   the daphnia for a few minutes and
   make notes about its
   appearance and behavior.

   
   

6. Draw
   a picture of the daphnia.
   

   
   

7. Use
   the pipette to re-capture the hydra and add it to the dish
   containing the hydra. Watch carefully what happens when the hydra
   and daphnia touch. Take
   good notes - you will be writing up your observations. (Watch
   the daphnia’s heartbeat - you can see the heart of the hydra
   through its skin.) In your notebook, describe what happens every 30
   seconds from first contact for at least 10 minutes or until the
   daphnia is completely eaten. Draw a few sketches to show what the
   daphnia and hydra look like.

   
   

Post-Lab

Hydras
have only a single opening to their gut - the mouth. Does a hydra
have a stomach? Explain your answer.

What
will happen to the parts of the daphnia that the hydra cannot digest?
How does this differ from the human digestive system?

Would
the hydra have been able to capture the daphnia without nematocysts?
Explain your answer.

Lab
Report

Your
completed typed lab report on this part of the lab should have all
your drawings and observations, as well as answers to all questions.
The lab report must be typed
and in complete sentences with correct grammar and spelling. It
should describe the actions you observed in
detail.

Be
careful not to use the word “it” if there’s any
doubt about what “it” means. Use correct terminology.

Your
report should also include the labeled drawing of the hydra and your
sketches of what happened as it attempted to capture the hydra.

BAD:
It’s grabbing it
with the things.

GOOD:
The hydra is using its tentacles to grab the daphnia.

BETTER:
The hydra is stretching out three of its tentacles to grab the
daphnia. The daphnia is struggling and kicking, but it’s
kicking more and more slowly and weakly.

Jethro - hydra vs human digestion

Last Initial: ____________ First Name: _______________________________________________________

Assignment "Jethro"
Human and Hydra digestive systems compared.

Type all answers on a separate paper and attach it behind this sheet.

Questions marked with a ** are optional, but must be answered if you want to get an "A" on the assignment. If you satisfactorily answer all the other questions, you will get a B+.
Many of the answers will be given during lecture. For extra helps, see the textbooks and/or:

http://kidshealth.org/kid/htbw/digestive_system.html (basic, but helpful)
http://www.dummies.com/how-to/content/running-through-the-human-digestive-system.html (a bit more detailed - quite good!)
http://yucky.discovery.com/flash/body/pg000126.html (cutesy, but good facts)
http://www.enchantedlearning.com/subjects/anatomy/digestive/

1. What are the three things that any digestive system must do?
2. What do the jaws, tongue and teeth do to aid the human digestive process?
3. Does a hydra have any structures that serve the same function as the human mouth? Explain.
4. **In the human digestive system, what is amylase, and what function does it serve?
5. What does the esophagus do in the human digestive system?
6. **What is peristalsis? Define and describe.
7. A hydra has no esophagus. What structures in the hydra carry out a similar function and how?
   
8. The human stomach contains strong acid; but it is NOT strong enough to dissolve the food. What IS the primary purpose of this acid?
9. How does the human stomach protect itself against being damaged by its own acid?
10. **What happens to the stomach acid when food passes into the duodenum?
    
11. What nutrients are broken down and absorbed in the human stomach?
12. What is the chemical that breaks down proteins
    
13. What are some of the most important differences between the human stomach and the gastro-vascular cavity of the hydra?
14. What are the main things that happen in the small intestine? (What materials are broken down?)
15. **What are villae?
16. How long is the long intestine? Why is it so long?
17. **Think about the previous question. What does the answer to that question suggest about a possible problem with the hydra's digestive system?
18. **What are villae, and how are they important to digestion? (I'll be especially happy if you use the concept of surface area in your answer.)
19. What happens in the large intestine? (What gets absorbed?)
20. **What part do bacteria in the large intestine play in digestion? Be specific?
    
21. What's a key difference between how a hydra and a human get rid of post-digestion waste?
22. Label the human digestive tract below. Label the mouth, esophagus, stomach, liver, small intestine, large intestine, rectum and anus. (**Label the gall bladder, pancreas and appendix.)
23. Label the hydra on the next page. Label the mouth, gastro-vascular cavity, and tentacles. (**show where the nematocysts are.)
    
24. Explain how the liver aids digestion.
    
25. Can you eat a new meal while still digesting a previous meal? Can a hydra? Explain your answer fully.