Lec 10- heterotrophs Flashcards
heterotrophy diversity
found across all organismal groups
herbivores
eats plants
carnivores
eats animals
detritivores
eat nonliving (dead) organic matter
What is food economics
the balance between ease of getting food and the quality of food
Ecological stoich
elements relationships in food
- relative abundance of C and N varies
- dictates what and how each type of heterotroph eats
plant stoich
high C:N ratio
- C used to build up structure and for photosynthesis
C>N
animals, fungi and bacteria stoich
low C:N ratio
less C needed
N>C
what 5 elements make 93-97% of biomass of plants, animals, etc?
C
O
N
P
H
carbon fxn
structure
oxygen fxn
part of water molecules
hydrogen fxn
part of water molecules
nitrogen fxn
part of amino and nucleic acids
phosphorus fxn
essential for cellular processes- ATP energy transfer
herbivory- food stoich
easy to get food- abundant
low quality food- rich in C but poor in N- difficult to digest
herbivory food
substantial nutritional chem challenges
- low N, high C
- cellulose and lignin strenthen tissue but increase C:N ratio = difficult to ingest and digest
- overcome plant physical and chemical defenses
physical: spines/thorns
chemical: toxins/digesting reducing compounds
- plants are poor food and animals must generally consume large amounts of food
koala diet
eucalyptus
- long digesting organs
- gut microbes
- long sleep
elephants diet
large amounts of food
10% of food to obtain nutrients
porcupines
defense strategies against predators (quills)
carnivory stoich
hard to get food but high quality of food
- nutritionally rich prey
- little variation in C:N ratio: prey available and have varied diet
- selection on nutritional requirements less strong, selection stronger on ability and efficiency of capturing and consuming diff preys
- adaptions to hunt effectively
detritivory stoich
easy to access but high and low quality
difference between detritivory and decomposition
both contribute to decomp and nutrient recycling
- detritivores = ingest and digest dead matter via internal processes (sea cucs)
- decomposers = directly absorb nutrients through chemical and bio processes (fungi)
detritivory
feed on nonliving organic matter
dominant food source is dead plant matter
dead plants rich in C and energy but poor in N
- N limiting to living plants
Nitrogen Use Efficiency in plants to reabsorb N before dropping leaves
- fresh detritus may have physical and chemical defenses present
- not limited by food
- abiotic and chemical composition more direct impacts (soil moisture)
mixotrophy
exploit more than one C source