03. SENSING & RESPONDING TO THE ENVIRONMENT Flashcards
(48 cards)
What does a proton pump do?
converts info → work using minimal E = ‘biological demons’ bc release E (work) from seemingly nowhere
What is homeostasis through the lense of order and energy?
homeostasis = maintaining internal order
b/c world is predisp to disorder → maintain HS = active work = req E = food → metabolism
t/f living orgs are goal-orientated bc seek to maintain HS → 1) survival + 2) reprod
What are the connections between the heat balance, water balance, feeding and respiration?
all comprise metabolism
How is metabolic rate measured in the modern day?
indirect ‘calorimetry’ = gas measurement
Requirements for basal metabolic rate
used for endotherms
- X moving, digesting or reprod
- in thermoneutral zone
- in inactive phase
- adult
Requirements for standard metabolic rate
used for ectotherms
- X moving
- X digesting
- @ known temp
- in inactive phase
- adult
- X reproducing
Requirements for resting metabolic rate
used for endo AND ectotherms
- X moving
- X digesting
- in thermoneutral zone
What is field metabolic rate?
‘doubly labelled water’
- incorp all E req org has
- generally x2-3 BMR for most spp
- org injected w ‘heavy water’ → take later sample + measure how much labelled (heavy) water has diluted
→ reveals E + H2O usage
What is the thermoneutral zone?
zone where endotherms can maintain stable body temp w/out E expenditure
Metabolic rate vs body size ratio
true for endo + ectotherms
M=aW^(3/4)
Describe the metabolic web
org’s ontogeny, life cycle + life history = all result of org’s metabolic process
→ feeding, assimilition (dig), growth, maintenance, devt + reprod = all comprise the ‘metabolic web’
Growth curves depend on…
metabolic rate across life span - diff for diff spp
e.g. guppy → M=W^(2/3) VS drosophila → MW^1 VS snail → M=W^(3/4)
Outline the difference between soft and hard limits
w/in soft limits org can reprod vs bw soft + hard lims org is in survival mode
e.g. temp - slightly too hot means difficult for org to find food/mate VS extreme heat → enzymes denat → death
i.e. cannot lower metabolic rate below BMR = hard lim
What is a metabolic niche?
continuous set of environ cond where org can reprod @ rate sufficient to maintain/grow pop
What is the outcome of enzymes denaturing?
irrev damage to cellular machinery → death
What are three modes of thermoregulation?
behavioural (e.g. kangaroo licks paws) + physiological + morphological
Factors determining metabolic niche
- food
- water
- temp
- salinity
- acidity
- mate selection
- predators
- disease
How does extreme heat cause bodies to fall apart?
irrev damage to enzymes (denat) + cell membranes (composed from 2 lipid layers → melting temp impacts fluidity of membrane → indir affects shape of enzymes - can cause them to denat)
Why do chipmunks sprawl on the ground in extreme heat?
maximising body contact with relatively colder surface → offload heat thru conduction
How is climate change impacting biodiversity in tropical areas?
generalists tend to live in high/low latitudinal areas vs specialisists live in tropics bc abundnace of resources = inc biodiv
h/e CC has disprop delet impact on tropical species bc forced to endure subopt cond → extinction of one spp → maj ramifications for delicate ecosystem - more prone to collapse bc specialisation
Information is provided by…
the presence OR absence of cues and signals
List the six sensory modalities that provide organisms with information
- chemical
- electricity
- light
- magnetic
- mechanical
- sound
Outline chemical modality
- oldest
- most taxonomically widespread
- relies on phys interaction bw odour + receptor
Outline electrical modality
- suited to aquatic environ
- used by sharks + monotremes
