Zooplankton

Question 1

Daphnia

Answer 1

1. Cladocera; sometimes called water fleas
2. Zooplankton
3. Very efficient at filter-feeding
4. Rostrum does not extend into an antennule

Question 2

Bosmina

Answer 2

1. Cladocera; sometimes called water fleas
2. Zooplankton
3. Very efficient at filter-feeding
4. Long antennules (like elephant trunk)

Question 3

Bythotrepes Longimanus

Answer 3

1. Common name: spiny water flea
2. Zooplankton
3. Planktonic Cladocera native to Eurasia and invasive to the Great Lakes region; may have spread through ballast water
4. Much larger than most other cladocerans
5. Long, spiky tail spine allows it to avoid predators
6. Voracious predator to other zooplankton and major threat to other cladocera; presence is associated with increase in production because of release from grazing pressure on algae

Question 4

Copepod

Answer 4

1. Large group of crustacean zooplankton
2. Zooplankton
3. 2 types of copepod
   a) Calanoid - Two antennae that are longer than the length of their abdomen
   b) Cyclopoid - Two antennae that are shorter than the length of their abdomen
4. Antennae are used in feeding and locomotion

Question 5

Rotifer

Answer 5

1. Known as “wheel animalcules”
2. Zooplankton
3. Planktonic and motile - in live material, move so quickly in the microscope you can barely see them
4. The lorica is a hard protein shell that protects from predation
5. Circular corona of cilia move in a rotating motion
6. Invertebrates
7. Important because they feed on many small algae
   and bacteria that might not otherwise be utilized in the lake system

Question 6

Zooplankton Characteristics

Answer 6

1. Cladocerans
2. Copepods
3. Rotifers
4. Protozoans

Question 7

Cladoceran

Answer 7

1. Water fleas
2. Daphnia and Bosmina
3. Filter feeders
4. Note their movement and feeding currents they generate

Question 8

Protozoan

Answer 8

1. Exhibit a myriad of life strategies including amoeboid, cilliated, testate, and attached forms
2. Move really fast across the microscope field of view
3. Vorticella

Question 9

Zooplankton

Answer 9

1. Most species are motile
2. Many perform diel
   migration to access their food source and to avoid predators
3. It is necessary to determine the biomass and species composition of zooplankton and hence their potential impact on the system because they are major herbivores and predators
4. Major food source for many lake organisms