Lesson 14 Flashcards
(45 cards)
are ectotherms usually just as warm as endotherms
yes
endothermy
- create body heat from within
- high metabolic heat production combined with insulation
- if you don’t insulate, what’s the point of heat production
- all chemical reactions produce heat and the less efficient they are the more heat they produce
- heat is always a product of metabolism
- the presence of insulatino is CRITICAL for being an encotherm
- why do we care how warm we are – many of our internal chemical reactions are temperature dependant
- faster chemical rxn can mean faster cognitive thinking/processing, digestion…
- out outside is changing also — not as much if aquatic
ectothermy
- animals do not have a high metabolic heat production and generally have little insulation
- use behavioral adjustmaents and some physiological adjustments
ex: the luzard will angle body in direction of direct sunlight
ANGLE is very important – the angle of the earth
– applies to the small animals as wekk - turning to get direct rays
- convection via air around it (heat rising)
- conduction via air and ground (touching)
- infred exchange with the sky and with rocks and other rocks around it
- animal can move between the sun and shade –> also orient differently
how does body temp affect behavior
– because it affects the speed of chemical reactions
– ex:
——- digestion
——- swimming speed
——- O2 consumption
some ectoderms can
- disperse pigment (melanin) from melanophores up into the process that darkens the skin –help the animal take up more heat – darkening skin
ectoderms and blood flow
- if you have blood very close to the skin – that blood is coming from the core of the body and the heat is being lost through the surface of your skin near your fingers
- what if you could turn off the blood flow to the areas with large amounts of surface area
WE DO IT – when our fingers go numb
lizards and their 3 factrors
- if warm on the inside and cold on the outside, then you might think that they should open up the blood vessels and dissipate heat
- even though the animal is warm, it doesn’t mean it’s warm enough
- have to reconsider its ideal temp
- should do the exact opposite
if the animal is warmer than it needs to be and the surrounding is colder,
you should open up blood vessels to cool down body temp
if body is warm, but not warm enough and the outside is cooler,
should not open up blood vessels and not allow for the more distal areas to get blood
when and whether an animal uses vasodilation, must consider 3 factors
- body temp
- ambient temp
- target temp
desert tortise
endangered – people have them as pets tho
- facing a lot of habitat loss, regular plant food supply has been lost from weeds that were not supposed to be there
- affected by dust and dirt – off road driving stirring up dirt, affecting respiratory
desert
potential for water loss exceeds water input
- lot of variation betwen temoerature and enviornment from day and night
in the mohobi desert
ground temp annually ranges from 0 to 50 degrees Celsius
- if you go 1 meter below the surface, you are only dealing with a 15 degree range
- therfoer lots of desert organisms live underground where the temperature fluctuations are greatly limited
- characterized by water scarcity - scarcirty of plants — scarcity of inscets
doubly labeled water technique
- quanify in animals metabolic activity – for weeks or months
—- energy expenditure when in the wild – no testing in the lab
^^ can answer with this techniuw
1st - appreciate the basic stoichiometry of metabolism
C6H12O6 + 6O2 –> 6H2O + 6CO2 - to do this water is made of isotopes of hydrogen and oxygen that are not normal
— The different water made with different isotopes are made in the lab and injected of a known volume of doubly labled water
—-What becomes of that water → over time there is a dissociated of the H and O ions – become spread throughout the whole body
—-Over time the injected water does get lost (gets metabolized) and gets excreted or evaporated, or breathed off
—-Eventually they leave the body —> O leaves through 2 routes, H leaves through 1 route – depending on how much metabolism has occurred the difference in the loss between H and O will change and can be computed
The degree to what they’re different will depend on how much time has passed and also the animal’s metabolic rate
- if the animal was involved in a lot of activity - the difference will be greatest
- calibrated to how much time has passed and can compute the amount of metabolic activity
drinking water
- certain small mammals in the desert never drink water
- all animals need water
- OPTIONS TO GET IT
- get water from plants (water in the cells of those plants)
- or they can make water
- all they did was take on glucose, breath in O2, and make water –> they can metabolically produce wter
- mostly how a lot of desert dwellers obrain water
for a chuchwaller
- chart tells us how much water is produced for what they eat
- fat produces the most water per gram
- in the dead of summer –> the chuckwaller barely emerges from underground
—- too hot
seasonal changes in water balance of chuckwalla
- almost no food in september
- much more food in may
- most of water comes from what they eat, little is metabolized
spadefoot toad (common desert amphibians)
- have permeable moist skin (becasue it is an amphibian)
BUtttttt their moist skin is not a handicap - they will dig these burrows that are damp in the ground –> it makes the burrow very humid —>allows them to take up water
- helps animal as ling as a lot of time is spent in the burrow
tadpoles of yellow legged frogs
- each dot shows position of tadpoles throughout the day
- note that its pretty chilly at 9 in the morning but less chilly at the bottom, so they all huddle at the bottom
- at 10 in the morning, warmer at the margins than the bottom – move to edges
hebron sound
big body of water off the coast of laberor
- have different strategies for surviving the cold
- temp of deep water doesn’t mate if it’s summer or winter
- animals do not freeze
- for something to freeze some crystilization must form
- you need a nucleatoer – you need some solid object ex: a grain of sand –> for ice crystals to grow around
- the deep waters of the hebron sound are so pure that they lack nucleators and there is nothing for the ice crystals to grow around
SUPERCOOLING
- ice does form around the top though
- animals above the deep water do not supercool – they make their own anticoolant to precent themselves from cooling — will synthesize low molecular weight antifreeze that will prevent them from freexzing
- some vertebrates tolerate frozen tisue
—– the wood frog is capable of tolerating frozen tissue
huge difference between endotherms and non endotherms in terms of energy usage
no bird or mammal is actually 1g of body mass (not true for ectoderms)
WHY^^^
- it is too expensive
- they have similar upper boundaries
- but when it comes down to the funamental property of SA and VOlume
– small objects cool off faster
– they give less thermal inertia
– small objects relative to the numebr of things that are making heat loss a lot of it
– being so small as an ectoderm – they get their energy from outside, and it is energetically favorable to be an ectoderm – to small to be eficient for an endoderm
no flat kind of shapes for endoderms
- more SA – more susceptible to heat loss
efficiency numbers
how good are these tissues in the body as using energy
– ultimately all energy converted into heat
^^^^ the goal for endotherms, but terribly inefficient for other processes
- turbinate bonds in the nasal passages that provide a large moist surgace
- the need to insulate –> presence of hair –> mammals (mostly) or aquatic mammals use blubber
- in surapsids they have feathers
endotherny
- high production of metabolic heat
- need isulation
-problem for evolution
—- dammed if you do, dammed if you dont
if you have all this insulation but are not producing heat = selected against
—- if you produce all this heat but have insulation = selected against
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