03. SENSING & RESPONDING TO THE ENVIRONMENT Flashcards
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
Outline light (visual) modality
dep on spp’s visual accuity + dist from obj
Outline magnetic modality (magnetoreception)
- used by bact + many animals esp birds. e.g. dunnock
- orient over long dist (mig) or short dist (homing)
Outline mechanical modality
- vibrations through substrate e.g. silk
- locate + det size of prey
- e.g. spiders
Outline sound modality
- echolocation
- varying freq - ultrasonic undetectable to humans
- e.g. bats (X avoid obstacles/locate prey when sound >20kHz bc X able to hear sonar feedback of own calls) + humpback whales
Examples of how the sensory modality utilised by a species depends on its habitat and lifestyle
e.g. aquatic animals use electrical modality
A signal/cue must be…
reliable AND readily discernable from bckgrnd noise
→ selection favours this
Signals can go undetected because…
- attenuate (fade)
- background noise e.g. bats when noise >20kHz → X hear own calls
Identify the differences between a signal and cue
signal = evolved + innate + mutually beneficial vs cue = learned + X evolved + exploitative
How can signalling be strategic?
false signalling = common adaption e.g. toxic colouring to deter predators
How are ant pheromones both signals and cues?
- signal for other ants
- cue for adult b’flies → mating/oviposition
- cue for spiders = pred on b’flies
Drawbacks of signalling
- physiological - energetically expensive e.g. courtship calls = more E than mvmt/rest
- exploitation - reveal location → cue for nat enemy
Examples of eavesdropping
- ants’ social alarm pheromone → alerts Habronestes spider to location → ants vulnerable bc distracted w soc alarm
- chicks begging calls
List prey defence adaptations and their matching predator counter-adaptations
- camo → improve sensory acuity
- mimicry → improve sensory acuity
- early pred detection → camo, faster
- active defence (chem, phys) → de-activation/de-toxification capacity, inc armaments
Degree of egg mimicry is higher in species with…
higher host rejection rates - evol arms race
Genotypes are a type of…
signalling bc tranfer of genetic info during reprod → det phenotypes
For asexual organisms, genetic information…
is transmitted directly + perfectly
Why are gametes dimorphic?
need to distinguish bw info transmitting (own DNA) + info recieving to avoid self-fertilisation
Where do asexual organisms typically thrive?
ag habitats bc homogenous
How do signals and cues play a role in sexual selection?
mate choice + male-male competition involve signalling = mating calls/displays
→ selection favours what Darwin called ‘organs of sense’ = attractive traits → more likely to reprod successful + pass to offspring
How is a reproduction an evolutionary paradox?
males + fems of same spp = common interest in spp surviving but both prioritise own genes = conflict of interest bc want to maximise mating opps + suppress others
How do male organisms prevent polyandry?
- interfere w fem signalling → dec comps
- phys interference
What is the evolutionary purpose of parental care? What are the drawbacks?
ensure offspring survives to sexual maturity → trandfer genetic info to next gen
high lvls of parental care = risky bc high E investment → compromises opp for further reprod
List the features of eusocial insects
- co-op care for young
- sterile castes → nest maintenance + care for young
- overlapping gens
Describe three ways an ectotherm might cool down
- shade-seeking - dec solar radiation
- climbing - cooler windier air
- panting - tongue exposed to air → inc rate of evap → inc heat loss
