MODULE 3 OVERVIEW Flashcards
What is a life meter?
takes data about physical / chemical conditions and tell you how far things are along the path to evolution of life on other planets / moons
Entropy of food
negative; highly ordered
Life feeds on . . .
negative entropy
generates metabolic products of higher entropies than the nutrients
What is a crystal?
stable structure w/ regularity
What kind of crystal is DNA?
a periodic crystal w. the capacity to store info
What makes organisms alive?
the way they receive & process info
How is the orderliness of an organism diff to that of a crystal?
- crystal is NOT living & does not actively maintain its orderliness via exchange of matter, energy and info w environment
- crystal is more vulnerable to degradation + descending into chaos
Two features of living things
1) goal-directed
2) exchange energy, matter, & info
What is entropy?
the natural tendency for energy to spread out more and more evenly over time
What is work?
the energy of a group of molecules all going in the SAME direction – there is an order to their movement
If work is using energy in an orderly manner, does that mean the 2nd law of thermodynamics is being violated?
No, as not all the energy from the food is actually going into doing the work
A portion of those molecules receiving that energy don’t cooperate
How do we measure heat production in organisms?
metabolic rate
2 levels of homeostasis
1) organism level (seeking shade)
2) molecular level (proton pump)
How does order come about in an organism? (2 things)
1) homeostasis
2) encoding
Flow of energy going INTO the organism must equal –
the flow of energy going OUT
How is metabolic rate measured?
1) direct calorimetry
2) indirect calorimetry (measures minute changes in CO2)
Examples of endotherms
mammals + birds
Features of endotherms
- maintain constant body temp
- homeothermic: vary how much metabolic heat they produce to keep their body temps constant
What is BMR (basal metabolic rate)? And what are the conditions
- used for endotherms
- animal not moving
- animal not digesting
- it is in thermoneutral zone
- inactive phase
- adult
- not reproducing
Examples of ectotherms
- reptiles + insects
Features of ectotherms
- do NOT generate extra heat to stay warm
- body temp fluctuates w environment
- we use SMR (standard metabolic rate)
What are the conditions for SMR? (standard metabolic rate)
same as for BMR, except that its body temp is a KNOWN temp
What are the conditions for resting metabolic rate (human metabolism)?
1) not moving
2) not digesting
3) in its thermoneutral zone
can be used for either endo or ectotherms
used in dietary studies
What is field metabolic rate?
metabolic rate of organism behaving naturally in the wild
- incorporates all the energy the organism has
How is field metabolic rate measured?
- using ‘doubly labelled water’
- organism captured + injected w heavy water
- later, take blood test & see how much water ha been diluted
(indirect measure of energy used)
What is the thermoneutral zone?
the point where there is NOT heating costs required for the animal to stay at its constant body temp (Where the basal metabolic rate is)
What is included in the metabolic web?
- feeding
- assimilation (digestion)
- growth
- maintenance
- development (maturation)
- reproduction
Metabolic rate is proportional to . . .
body weight (to SOME power)
What happens if organisms can’t find the right set of environmental conditions within their optimal range?
- may be unable to SURVIVE
- may be unable to MOVE to find food
- might spend too much energy / water regulating their body temp
- may survive but NOT reproduce quickly enough
What are soft limits?
areas just outside optimal region
Define poikilothermic
means variable temp
Ectotherms cannot. . .
generate enough heat INTERNALLY
Koalas try to regulate their body temp through . . .
CONDUCTION
Advantage of endotherms
can elevate their metabolic rate when it’s too cold to keep warm
Disadvantage of endotherms
- have to eat more + have a more reliable source of food
- might die if they release too much water to try and cool down
Why is there a rise in metabolic rate after the thermoneutral zone?
- start to do behaviours like licking / panting which cost energy
- using extra energy to behaviourally regulate their muscular activity
Why is the thermal tolerance of species living in the tropics NARROWER?
- you have more ‘generalists’ in high latitude areas
- more ‘specialists’ in low latitude areas (equator)
Endotherms - their regulation of body temp is. . .
INDEPENDENT of external sources
What does it mean to be homeothermic?
having a relatively UNIFORM body temp maintained nearly independently of env temp
What does sensory modality depend on?
- depends on whether the species LIVES + its LIFESTYLE
Signals must be. . .
RELIABLE + READILY DISCERNABLE from background noise
Spatial / temporal variation
e.g. food is patchily distributed in space - so needs to be detected & predators might arrive quickly
What is a signal?
an evolved means of actively conveying info & influencing the behavior of receivers
What is a cue?
passive, non-evolving biological & environmental traits that inherently provide the observer with info
What is a pheromone?
substance which is secreted to the outside by an individual and received by a 2nd individual in the same species
3 features of signal / cue
1) no intrinsic meaning
2) provide and convey info
3) must be recognizable
What are the 6 sensory modalities?
chemical, electrical, light, magnetic, mechanical, sound
E.g. of a signal
flashing lights as a signal to indicate location for mating
E.g. of a cue
red-necked wallabies use the odor of feces as a CUE revealing the likely presence of predators
What is meant by signals attenuating?
signals, and the info they provide, may not reach their INTENDED RECEIVER because they ATTENUATE as they RTAVEL through the env
What might affect the ability of a signal to reach a receiver?
background noise
What is meant by signals are ‘strategic’?
bright colouration reveals toxicity and thus reduces likelihood of predation
Signals and efficacy
efficacy: same info, different impact
One difference b/w signals & cues
signals benefit both the signaler and receiver, whereas cues do not
How does an animal KNOW what is a signal or cue and how does it know how to respond?
the source of info that allows animals to behave:
1) innate
2) learned - a behaviour that is modified as a result of the animals’ experience of its environment
e.g. digger wasps use landmarks to LEARN the location of their nests
What are some costs to signaling?
1) physiological (drain on resources during GROWTH or during immediate PRODUCTION OF SIGNALS)
2) exploitation (eavesdropping) – signals or cues may be intercepted by an unintended receiver (predators or parasites)
What are social alarm pheromones?
chemicals that elicit particular behaviors amongst the individuals within a colony
– spiders easily capture displaying ants
Example of eavesdropping interspecific cues
- butterflies are attracted to ants
- but so too are spiders
- spiders can capture the butterflies that are flying around
What are intra-specific cues?
WITHIN SPECIES
- related and detected by members of the same species
What is masquerade?
a type of camouflage that prevents recognition by resembling an uninteresting or unimportant object, like a leaf / stick
What is motion masquerade?
movement improves cyprisis and thus reduces likelihood of predation
Define mimicry
an evolved resemblance b/w an organism & another object, often an organism of another species
What is Batesian mimicry?
resembles a noxious or dangerous model
- predators avoid eating both the model & mimic
What is Mullerian mimicry?
2 or more species have similar anti-predator traits & similar warning signals, but do not share an immediate common ancestor
- to their mutual benefit
What is coevolution?
a process involving pairs of species whereby changes in the traits of individuals of 1 species causes reciprocal changes in the other species OVER evolutionary time
What are antagonistic interactions?
may lead to reciprocal evolutionary change – “arms race”
What is ‘arms race’?
a struggle b/w competing sets of co-evolving genes, traits, or species that develop adaptations and counter-adaptations against each other
Asexual reproduction is more common in. . .
agricultural habitats that are typically homogenous
Modes of reproduction that remove the hassle with sex
1) facultative parthenogenesis
2) hermaphroditism
What is mean by sexual dimorphism?
differences b/w the sexes
What is sexual selection?
when there is competition between members of one sex (typically males) for reproductive opportunities with the other sex (typically females)
Both mate choice and male-male competition involve. . .
signalling
What are male counter-adaptations to polyandry
1) physically preventing her from mating
2) interfering with female signalling
Polyandry is the ‘best’ outcome for . . .
females
Polygyny is the ‘best’ outcome for the
alpha male (not the beta male)
What is foraging?
act of gathering wild food for free
Features of eusocial insects
1) cooperative care of young
2) sterile castes help
3) overlapping generations
