Daphnia, also known as water fleas, are small freshwater crustaceans that range in size from 0.5mm to 1cm. There are over 100 species of Daphnia. While vertebrates and some invertebrates contain hemoglobin in their red blood cells to transport oxygen, Daphnia do not have respiratory systems or red blood cells and instead rely on diffusion of oxygen through their transparent outer shells. However, in hypoxic conditions Daphnia can increase hemoglobin production to carry more oxygen through their circulatory systems to their tissues. Daphnia reproduce both sexually through resting eggs in unfavorable conditions and asexually through parthenogenesis in favorable conditions,

1. Daphnia

2. Background information on Daphnia
1(Daphnia live in freshwater.
2(Their size ranges from 0.5mm to 1cm.
3(There are more than 100 species

3. Interesting facts about Daphnia
*Daphnia are called “water fleas”
)jerky motion(
*Carapace of a Daphnia is transparent.
*Daphnia and tail spines.

4. Hemoglobin
1-Found in all vertebrates and some invertebrates
2-Contents : (protein + iron(
3-Function : (transport oxygen to all body tissues(

5. Daphnia and hemoglobin
Complex animals Daphnia
1-Respiratory system and
red blood cells
Present Absent
*They obtain oxygen by
diffusion through the
outer carapace of the
Daphnia.
2-Position of hemoglobin Inside red blood cells
(intracellular(
*Circulatory sytstem is
opened type , no blood
vessels.
* Hemalymph cavity.
3-Need of hemoglobin High level to survive Don’t need high level to
survive

6. *In hypoxic water conditions Daphnia can
increase hemoglobin production.
*In normal conditions, Daphnia can lower
hemoglobin production.
*This will allow the Daphnia to carry more
oxygen to body

7. Reproduction in Daphnia
In Favorable conditions : Parthenogenetic eggs.
In unfavorable conditions : Resting eggs.
Daphnia eggs and ephippium.

9. Importance of Daphnia
They are very
important in the
food chain series.

10. Daphnia are indicator species to test the effects
of toxins.
DaphTox II – Biomonitoring using Daphnia

11. *Studying the effects of stimulant substances
on Daphnia.

12. George Magdy