1. Daphnia
Lesson 16 Notes

3. I. Basic Info Freshwater Crustacean Three part body
Head, thorax, abdomen

4. II. Gender Mostly female Can lay up to 400 eggs Two types of eggs
Summer eggs
Parthenogenetically – without fertilization
Within broad chamber
Winter eggs
Fertilized by male
Released by female and then hatch in summer
Always contain female Daphnia that will reproduce parthenogenetically

5. eggs

6. III. Structures 2 pair antennae 1 large pair for movement
Single compound eye
5-6 2-branched appendages from thorax
Feeding of algae and phytoplankton
Digestive tube from mouth to anus
Often green from phytoplankton
Heart
Open circulatory system (blood not confined in vessels)
Gas exchange

9. IV. Heart Rate Averages 230-300 beats per minute HR increases with
Increase in light
Increase in temperature
Caffeine (stimulant)
Nicotine
HR decreases with
Alcohol (depressant)

10. Daphnia heart rate

11. Daphnia Heart rate experiment with caffeine and alcohol solutions