Feeding Flashcards

1
Q

feeding definition

A

gathering and ingesting food

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2
Q

digestion

A

breakdown and transferring required nutrients into the body

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3
Q

Ways of obtaining nutrients

A

 Autotrophic – including plants algae and some bacteria – able to produce their own food and energy
 Heterotrophic – consumers – all animals must obtain nutrients from other plants or animals for energy and nutrients

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4
Q

Short food chains vs long

A

Short food chains deplete less energy prior to consumption thus more efficient than long food trains

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5
Q

Why did animals evolve within the sea

A

The ocean was a source of more of a more constant environment, so they didn’t have to evolve ways of dealing with so many different environmental factors

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6
Q

earliest metazoan marine life

A

Ediacaria period - 550myr ago

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7
Q

Feeding behaviours within ediacara period

A

detrivores and carnivores were able to capture protists and bacteria
* Primary productivity was and still is limited to the surface areas of the ocean
* Benthic organisms were and are dependent on organic detritus falling from the surface of the ocean

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8
Q

Exceptions of benthic organisms feeding on detritus

A

hydrothermal vents and cold seep ecosystems

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9
Q

Feeding methods

A

Small particle feeding
Large particle feeding
Fluid feeding

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10
Q

Small particle feeding

A

suspension or filter feeding – consume material suspended in water column
* Specialized flagellated cells – choanocytes – move flagella to draw in water through pores
* No gut – direct cellular ingestion of captured food

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11
Q

Filter feeding – mucociliary

A
  • External mucociliary mechanisms – use motile cilia and mucus to capture food particles of the appropriate size
    1. Create a current of water bearing particles
    2. Separation of particles from the water
    3. Transfer of particles to mouth
    4. Ingestion occurs
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12
Q

Filter Feeding - Amphiuridae

A
  • Feed by holding their arms into the water column and trapping particles in flowing water
  • Particles are moved to the mouth using groove on their oral side
  • In stagnant water they switch to deposit feeding
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13
Q

Deposit feeding

A

ingestion of living and non-living organic matter (crabs)

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14
Q

Setae

A

external setae or cirri = long closely spaced feeding setae on numerous appendages used to collect food

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15
Q

Baleen whales

A

– two sets of baleen plates – (keratin) sieve food particles from the water

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16
Q

Basking sharks

A

can strain 2000 L of water per hour swim with mouth continuously open to feed on the zooplankton – gill rakers trap and filter out plankton – mouth closes to swallow

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17
Q

Deposit feeders

A
  • Consume large amounts of organic matter within sediments
  • Vital for the regeneration of nutrients and enhance benthic productivity
  • Eg. Ragworm
18
Q

Radula adaption

A

found in many gastropods – used for scraping algae off rocks – can be found in carnivorous snails to rasp flesh off dead animals
- Structure = many sets of small teeth in which move back and forth to scrape off algae the structure is then pulled back into the buccal cavity to ingest the particles

19
Q

Aristotles lantern

A
  • Sea urchins possess a very intricate mouth apparatus – Aristotles lantern which is comprsed of a powerful set of jaws – makes them a very successful herbivore
20
Q

Hunting behaviour

A

some species feed by targeting and subduing individual food items, but others will work together in teams and in pods to chase the prey that they are after

21
Q

Orcas

A
  • Eat fish, squid, sea otters, and seals by attacking them with sharp teeth.
  • Behavioural specialists depending on prey
  • Hunt in packs (e.g., pods of five) for higher success rates.
  • Prey is divided among the group after catching it.
22
Q

Dolphins

A
  • Hunt in pods.
  • They corral bait balls by swimming around them to bunch up the fish.
  • Dolphins slap the bait ball with their tails to stun the fish - float to the surface, making them easier to catch.
  • Dolphins also use a technique called mud nets to trap fish
23
Q

Specialised radula

A
  • drill snails- that cuts a hole through shells – either sucks out living tissue OR injects venom to paralyze
24
Q

Nematocyctes

A
  • Exclusively found in the phylum Cnidaria
  • Coiled, hollow, barbed thread that quickly turns outward
  • Often contains poison
  • Prey capture and defence
25
Q

Photosynthetic symbiosis

A

endosymbiotic algae produce nutrients through photosynthesis – passed on to corals cells
 Coral emit waste produce (NH4 etc) consumed by endosymbiotic algae

26
Q

Chemosynthetic symbiosis

A

(hydrothermal vent worms)
-They have a symbiotic relationship with chemoautotrophic bacteria and lack a mouth, gut, or anus.
 Food comes from sulfur-oxidizing chemoautotrophic bacteria within a trophosome.
 Require hydrogen sulfide, found near hydrothermal vents.
 Sulfate is produced in the trophosome and voided across the gills.
 Bacteria produce energy and transfer it to the worm.

27
Q

Intracellular digestion

A
  • Gastrovascular cavity - has one opening and a blind tube or cavity that serves as mouth and anus
  • Digestive enzyme in tubular cavity break down food and food particles are engulfed by cell lining within the gastrovascular cavity
28
Q

Extracellular digestion

A
  • Alimentary canal – digestive tract with a mouth at one end and anus at the other end
  • Food is ingested in through the mouth passes through the esophagus and stored in the crop
29
Q

Evolution of the through gut

A
  • Allowed for continuous food processing
  • Increased ability to process bulky and low quality foods
  • Multiple mechanical and chemical processes along length of gut such as changing pH to optimise enzyme activity
30
Q

Gut structure

A
  • Foregut
  • Midgut
  • Hindgut
31
Q

Foregut

A

ectodermal in origin = ingestion and mechanical breakdown of food
* Buccal cavity – saliva to lubricate passage of food and enzymes to start digestion
* Pharynx – pump food down to gut – aid mechanical breakdown and mixing of food
* Esophagus/crop – either carries food directly to stomach (crop is associated w animals that have large infrequent meals)

32
Q

Midgut

A

– endodermal in origin = nutrient absorption
* Muscular stomach – starts or continues the comminution of food = sometimes mechanical breakdown
* Secretory caeca – branch off immediately after stomach = production of digestive enzymes and absorption of digested food
* Intestine – intracellular digestion in lower invertebrates = extracellular digestion in animals processing large masses of food

33
Q

Hindgut

A

– ectodermal in origin = elimination of waste through anus
* Rectum – selective reabsorption of water and salts from food
- Site of faecal pellet formation - highly distinctive shapes can be used to identify species presence

34
Q

Types of meal processing – reactor models

A
  • Batch reactor
  • continuous flow reactor with mixing
  • continuous flow reactor without mixing
35
Q
  • Batch reactor
A

– each meal is processed before the next meal enters

36
Q
  • Continuous flow reactor without mixing
A

meals line up so they don’t mix but each meal processed for longer than batch reactor

37
Q
  • Continuous flow reactor with mixing
A

– new meals mix with meals that have already undergone some processing

38
Q

Secondary loss of the through gut

A
  • 25% of 30,00 fish spp have lost ability to use stomachs because of a change in diet - no need for stomach enzymes
  • Lost gene for gastric proton pump and for pepsinogens
  • food is passed into the stomach in a cord of mucus
  • Stomach acids reduce viscosity of mucus and particles are released
  • Remaining gut is alkaline – restores viscosity of the mucus and production of faecal pellets occur
39
Q

Chordates

A

mucus chord moved to stomach by cilia of the pharyngeal basket and esophagus

40
Q

Bivalve digestive strategies

A
  • 2-phase digestive system: rapid intestinal pathway OR slower, glandular pathway
  • Evolved this digestion strategy to avoid excess assimilation of metals
  • Reduced ingestion rates under high Cr
  • Reduced proportion processed by glandular digestion under high Cr
  • Able to modify processing to reduce exposure to Cr
41
Q

Gut microbes – herbivorous fish

A
  • Different algae types have unique compositions of polysaccharides.
  • Herbivorous fish use specific enzymes to break down these large polysaccharides to obtain energy from algae.