Week 2 – Holoplankton

Question 1

What are holoplankton?

Answer 1

Permanent members of the plankton

Holoplankton includes organisms that spend their entire life cycle in the planktonic phase.

Question 2

Which group makes a major contribution to the global biomass of mesozooplankton?

Answer 2

Copepods

Copepods are small crustaceans found in the sea and nearly every freshwater habitat.

Question 3

What are protozooplankton?

Answer 3

Heterotrophic flagellates

Protozooplankton includes single-celled organisms that are primary consumers in the planktonic food web.

Question 4

What is the size range of microzooplankton?

Answer 4

20-200 microns

Question 5

What methods do protozooplankton use to consume large prey?

Answer 5

3 methods:
* Palium feeding
* Tube feeding
* Direct engulfment

These methods reflect the diverse feeding strategies among protozooplankton.

Question 6

What is Noctiluca scintillans known for?

Answer 6

Large dinoflagellate that feeds on phytoplankton, bacteria, and copepod nauplii, forms red tides, sea sparkle

Question 7

What are the two types of ciliates in protozooplanktons?

Answer 7

Loricate (with shells) and aloricate (without shells)

Ciliates are characterized by the presence of cilia used for feeding and movement.

Question 8

What are radiolarians?

Answer 8

Protozooplankton with mineral skeletons made of strontium sulfates and silica

They have a fossil record dating back to the Cambrian period.

Question 9

What characterizes foraminiferians?

Answer 9

Cell surrounded by a calcium carbonate, many-chambered shell

Foraminiferians can be benthic and are generally omnivorous.

Question 10

What are some reasons organisms use bioluminescence?

Answer 10

Feeding, self-defense, finding mates

Question 11

What class do most Cnidaria belong to?

Answer 11

Class Tentaculata

This class includes organisms that typically have tentacles.

Question 12

What is unique about the class Beroida in Cnidaria?

Answer 12

They are without tentacles and exclusively eat other tenophors

Question 13

What are the features of Scyphozoa?

Answer 13

Deep sea jellyfish with mesopelagic features

They exhibit red coloration and bioluminescence.

Question 14

What is a siphonophore?

Answer 14

A colonial organism made up of specialized individuals

The colony includes various zooids with specific functions.

Question 15

How do ctenophores swim?

Answer 15

Using ciliary plates known as comb plates

Question 16

What does ‘Sp.’ vs ‘spp.’ signify?

Answer 16

Sp. is singular and spp. is plural

Question 17

What characterizes Thecosomata in Mollusca?

Answer 17

Sea butterflies with thin calcified shells

They have wing-like lobes for swimming.

Question 18

What are Gymnosomata in Mollusca?

Answer 18

Sea angels without shells

Question 19

What is the size range of Chaetognatha (arrow worms)?

Answer 19

2-12 cm

Question 20

What factors determine the size and type of prey a chaetognath can eat?

Answer 20

External factors, swimming speed relative to prey, size of grasping spines and mouth

Question 21

What are the three orders of pelagic tunicates?

Answer 21

Salps, doliolids, and pyrosomes

Question 22

What class comprises the vast majority of holoplankton?

Answer 22

Crustacea

Question 23

What class of crustaceans is mostly warm water and usually neritic?

Answer 23

Ostracods

Question 24

What distinguishes Order Amphipoda?

Answer 24

No carapace and body usually laterally flattened

Question 25

What is unique about Order Mysidacea's eyes?

Answer 25

Moveable eye on peduncle

Question 26

What is significant about Euphausiacea (krill)?

Answer 26

Dominate zooplankton biomass and are crucial for megafauna food webs

Question 27

What are the two main types of copepods?

Answer 27

Calanoids and cyclopoids

Question 28

What is the life cycle of copepods?

Answer 28

Eggs hatch into nauplii, undergo naupilar and copepodite stages

Question 29

What is the main characteristic of calanoids?

Answer 29

Long first antennae and biramous second antennae

Question 30

What is the primary habitat for cyclopoids?

Answer 30

Mainly freshwater

Question 31

What is the feeding behavior of harpacticoids?

Answer 31

Graze on algal biofilms and bacteria

Question 32

Which features can be used to distinguish between a mysid and a krill?

Answer 32

These anatomical features are key for differentiating between mysids and krill: Eyes on stalks: Krill usually have compound eyes on stalks; mysids often do not. Sensory statocyst: Mysids have statocysts (used for balance) at the base of their uropods, which krill lack. Carapace fusion: In krill, the carapace is fused to the thorax, while in mysids, the carapace is not fully fused.

Question 33

Which phylum uses sticky colloblasts to capture prey?

Answer 33

Ctenophors

Question 34

Which Class of crustacean has a bivalved 'shell' or carapace?

Answer 34

Ostracods

Question 35

Including the egg, how many life stages are there in the copepod life cycle?

Answer 35

13

Question 36

Pallium feeding

Answer 36

- A veil of cytoplasm, the pallium, surrounds prey - Digestive enzymes are secreted onto the enveloped prey - Only digested material is brought into the cell body as the pallium is retracted.

Question 37

What are the 5 orders of Radiolarians?

Answer 37

Acantharia, Nassellaria, Spumullaria, Collodaria, Taxopodia.

Question 38

What features aid buoyancy in radiolarians?

Answer 38

Vacuoles, lipid droplets and pseudopodia