LSM2231 - Feeding
Surface absorption
Fluid feeding
Seizing of prey
Filter/Suspension feeding
Transport mechanism - nutrients (aa...) and endocytosis - large molecules
Using body surface to absorb food from surrounding
Case study - African sleeping sickness
eg. Protozoans, endoparasites, aquatic invertebrates etc
eg. Sponges, bivalve mollusks, flamingo, whale etc.
Used by aquatic animals to capture small food zooplankton/phytoplankton
Food obtained via water current flowing through the organism
Current created by flagella + hydrostatic pressure difference
Cutting and licking - bats, hagfish
Piercing and sucking - mosquitoes, fleas, bedbugs, lice...
Saliva contain analgesic to prevent host from noticing ⭐
Toxins to immobilise prey - snakes
Use mouthparts and other appendages to capture food
Living without food
Symbiosis
Suspended animation
Aestivation
Hibernation
Artificial suspended animation: cryonics - freezing of human bodies with no harm to cells/tissues/memories
After feeding - DIGESTION
Intracellular
Extracellular
Primitive organisms
By enzymes or acidic vacuoles
Batched reactors
Using blind tubes/cavities ⭐
One-step each aka one batch of food processed + eliminated before the next one is taken in --> pulsed fashion ⭐
eg. hydra
Continuous-flow stirred tank reactors
Hollow tube opened at both ends
Food flown in, digested and excreted continuously
eg. ruminant
Occur in cytoplasm
Plug-flow reactors
Food digested along the tube-like digestive reactor in bolus
Human intestine, and other vertebrates
Composition of food varies along reactors (progressive process)
Some organisms have a combo of plug-flow and continuous-flow reactors eg. cow
Extra point to note
Quality of food affects time for digestion in continuous-flow digestive reactors
Transit time affectors
Body mass
Body temperature