Feeding and Digestion

Question 1

What is extracorporeal digestion?

Answer 1

breakdown of nutrients outside the body

Question 2

What is extracellular digestion?

Answer 2

• breakdown of nutrients in a gut chamber

Question 3

What is intracellular digestion?

Answer 3

breakdown of nutrients in the cell

Question 4

What is the ultimate challenge of organisms, and how is it solved?

Answer 4

cellular capture of nutrients

solved by phagocytosis (eating) and pinocytosis (drinking)

Question 5

What is endocytosis?

Answer 5

engulfing of food particles at the cell surface

Question 6

What is phagocytosis?

Answer 6

plasma membrane extends and encircles particles

Question 7

How does phagocytosis work? (3)

Answer 7

pinches off pocket in the cell, becoming a food vacuole

digested within the vacuole and released

remaining waste is carried to the surface and fuses with the plasma membrane and is discharged (exocytosis)

Question 8

What is pinocytosis?

Answer 8

molecule-sized particles are taken up by the cell

Question 9

How does pinocytosis work (3)?

Answer 9

dissolved in fluid like body or sea water

channels form on the cell surface, filling with liquid and pinches off into vesicles

occurs in cells lining body cavity where extracellular digestion has already taken place

Question 10

What groups lack a digestive tract?

Answer 10

Porifera, Placozoa, tapeworms, acanthocephalans

Question 11

What is an incomplete gut, and where is it found?

Answer 11

only one opening which food is ingested and eliminated

Cnidaria, Xenacoelomorpha, Platyhelminthes

Question 12

What is a through/ complete gut?

Answer 12

both mouth and anus for one-way flow of food

Question 13

How does anatomy and consumption correlated?

Answer 13

anatomy and physiology of gut is tied to quality and type of food consumed

Question 14

How does diet affect gut?

Answer 14

herbivores have specialized chambers to digest

carnivores have shorter, simpler guts

Question 15

What is suspension feeding?

Answer 15

removal of suspended food particles from the surrounding medium by some sort of capture, trapping, or filtering

Question 16

What is the general process of suspension feeding?

Answer 16

transport water past feeding structure > remove particles from water > transport particles to mouth

Question 17

What groups have suspension feeding?

Answer 17

sponges, ascidians, appendicularians, brachiopods

Question 18

What limits suspension feeding?

Answer 18

size limits of food determined by capturing device, gravity, or nutritional quality

Question 19

What does suspension feeders eat?

Answer 19

consumes bacteria, phytoplankton, zooplankton, and detritus

Question 20

How does suspension feeding correlate with Reynold’s number?

Answer 20

captures particles from water at low Reynolds number

Question 21

What is the consequence of suspension feeding at low Reynold’s numbers? (2)

Answer 21

cost a lot of energy to filter

can use mucus and cilia to capture food (contact suspension feeders)

Question 22

What is done to solve suspension feeding at low Reynold’s numbers? (2)

Answer 22

can use mucus and cilia to capture food (contact suspension feeders)

depends on either currents or energy to move water

Question 23

What is scan and trap feeding, and what groups possess it?

Answer 23

move water over body, detect food, isolate it in water, and process that only

crustaceans and bryozoans

Question 24

How do crustaceans capture food? (2)

Answer 24

from current

some capture setae can be seen in legs to help move and collect food

Question 25

What is a mucous net?

Answer 25

mucous net- using patches of mucous to catch food

Question 26

How do benthic burrowers feed?

Answer 26

actively pump water through burrow to pass through mucous sheet (annelids)

Question 27

What is ciliary-mucous mechanism, and what groups possess it?

Answer 27

rows of cilia carry a mucous sheet across some structure while water is passed through or across it hemichordates, polychaete

Question 28

What is tentacle/ tube feet suspension feeding, and what groups possess it?

Answer 28

capturing larger food particles with structure echinoderms and cnidarians

Question 29

How does feeding rate and food concentration correlate, and why (2)?

Answer 29

feeding rate increases with food particle concentration to a plateau high particle concentration can clog or inhibit feeding sediment can decrease filtering

Question 30

What are deposit feeders?

Answer 30

obtain nutrients from the sediment

Question 31

What are direct deposit feeders, and what groups have it?

Answer 31

swallow large quantities of sediment and digests organic while passing unusable material polychaete annelids, snails, earthworms

Question 32

What are tentacle utilizing/ selective deposit feeders, and what groups have it?

Answer 32

use of tentacles to consume surface sediment sea cucumbers, bivalves

Question 33

What is coprophagy?

Answer 33

deposit feeders relying on feces

Question 34

Why is coprophagy beneficial?

Answer 34

prevents organic debris accumulation and allows for nutrient cycling

Question 35

What is macroherbivory, and what is it characterized by?

Answer 35

requires biting and chewing mechanisms characterized by development of hard teeth and muscles

Question 36

Mechanisms of macroherbivory (3)?

Answer 36

radula- muscular, beltlike rasp with chitonous teeth in molluscs polychaetes have a proboscis to tear off algae mandibles are used in arthropods

Question 37

What does active predation involve?

Answer 37

prey location requires a sophisticated nervous system and sense organs

Question 38

What are motile stalkers, the groups, and what do they use to hunt?

Answer 38

actively pursue prey (polyclads, nemertea) uses chemosensation to locate prey

Question 39

What are lurking predators, groups, and its costs?

Answer 39

sit and waits for prey to come into capture distance (mantis shrimp, spiders) cost is building traps

Question 40

What are sessile opportunists, and groups?

Answer 40

immobile lurking predators (jellyfish, barnacles)

Question 41

What are grazing carnivores?

Answer 41

picks up epifauna on substratum

Question 42

When may cannibalism occur?

Answer 42

when small individuals team and attack a larger individuals

Question 43

What is filial cannibalism?

Answer 43

parent eats weak offspring

Question 44

What is dissolved organic matter?

Answer 44

organic carbon in the sea

Question 45

What dominates in organic matter, and what organisms release them?

Answer 45

amino acids and carbohydrates dominate algae releases copious amounts - example- coral mucus

Question 46

Who can absorb DOM, and what is it used for?

Answer 46

marine invertebrates are all capable of absorbing it unclear of actual use of it for invertebrates

Question 47

How does DOM absorption work (2)?

Answer 47

absorption occurs across body wall or gills freshwater organisms have a harder time uptaking DOM

Question 48

What is chemoautotrophy, and whee is it common in?

Answer 48

using CO2 to oxidize hydrogen sulfide, ammonia, methane, and ferrous ions for energy uses chemoautotrophic bacteria (mussels, clams) common in aerated soils, hydrothermal vents, and symbionts