BIO 434 Midterm 2

modes of feeding: herbivory and grazing

(microbial/micro algae/ macroalgae/ plants) radula in invertebrate gastropods bony plates or teeth in fishes teeth in herbivorous mammals invert gastropods (all mollusk except bivalves) have a radula -raspy tongue fishes have unique bony plates/teeth -scrape algae -parrotfish -FW fish bottom feeders teeth in herbivorous mammals specialed for grinding cellulose

molecular evolution of chytochrome c oxidase underlies high altitude adaptation un the bar-headed goose

-bar-headed geese fly at up to 9000m elevation during migrations over the Himalayas -during this migration they sustain high metabolic rates while experiencing high-altitude hypoxia -Scott et al. investigated the cardiac energy metabolism and O2 transport in this species to understand molecular and physiological adaptations to high-altitude -they compare bar-headed geese to closely related low-altitude geese (pink-footed and barnacle)

modes of feeding: symbioses

-coral gets energy from photosynthetic zooxanthellae (type of dinoflagellate) (glucose for coral and coral provides protection) -hydrothermal vent communities are based on symbioses with H2S consuming bacteria (non-photosynthetic; chemosynthetic) -microbial community in the guts of all animals glucose for coral and coral provides protection chemosynthetic bacteria gets E from chemicals (H2S) -hydrothermal vent worms have (riftia) living bacteria in trophisome -get bulk nutrients through the bacteria

diving animals and myoglobin

-data shows differences in the overall amount of oxygen stored in different places in the body in humans and then in diving seals with different dive durations -lungs, blood, myoglobin (stores O2 in muscle), interstitial fluids -interstitial fluid around the same between the species -diving mammals have high myoglobin concentrations -oxygen stored in blood is higher in diving seals (increasing oxygen carrying capacity in blood accomplished by increasing hemoglobin/myoglobin, or increase blood volume) (oxygen saturation around 2x higher in blood compared to humans before they dive) -slight decrease of oxygen stored in lungs in diving animals because lungs will shrink in increasing pressure the further they go deep diving animals have increased myoglobin to act as an oxygen store and...

acclimation response when 'lowland' mammals travel to high altitude

-hyperventillation (increased breathing rates) -increase RBC counts -decrease in muscle fiber diameter (the bigger the fiber the low the SA/V ratio means less access to oxygen) -increase in the concentration of hemoglobin and myoglobin -suppression of metabolism (hypometabolism) in some tissues, reducing O2 demand -suite of metabolic changes to increase the yield of ATP per O2 many of these responses are also present as adaptations

Oxygen challenges and external respiration in aquatic environments: forms of external respiration (breathing)

-many aquatic animals breathe through their skin (simplest and smallest animals with either flattened bodies or round and about 1 mm, dont need complex gas exchange structure because flat/small and can get adequate oxygen) as organism get bigger and more complex they begin to use gills -others use gills, which increase the surface area for respiration in aquatic animals gills: -can be a little bump (sea stars) called tuft gills -aquatic insects/amphibians will have filament gills (highly branched, high SA evaginations of skin that are very permeable and very associated with vasculature) -lamellar gill: most complex (vertebrates, elasmobranchs, teleost fishes, largest crustaceans) lamellar gills: -layers of lamelle to increase SA where gas exchange can happen -one major way to deal with low oxygen levels with gills

how does environment influence feeding mode? freshwater

-same as marine except also... -mostly micrograzing of microbial communities/algae. Herbivory beyond this is rare due to lack of macrophytes in most lakes -predatory insects that exploit the 'surface tension' of water for a habitat (ie water striders) --requires calm water -strong diel and seasonal variation in food abundances

Oxygen challenges and external respiration in aquatic environments: breathing in amphibians

-the respiratory gas exchange surface typically changes across development (gill -> lungs/skin) graph: relative oxygen uptake in skin, gills, lungs over different developmental stages -around 50% oxygen takes place in gills and 50% in skin as tadpoles -adult form major oxygen uptake through the lungs (about 80%) only about 20% in the skin Graph 2: CO2 excretion not the same - for juveniles about 50/50 across gills and skin -adults eliminate most CO2 though skin (about 80%) -juvenile frogs rely on both gills and cutaneous respiration -adult frogs rely on both cutaneous respiration and lungs

Important properties of gases (in solution)

1. Different gases have different solubilities in aqueous solution 2. The solubility of a gas in an aqueous solution decreases strongly as temperature increases 3. The solubility of a gas in aqueous solution decreases with increasing salinity Blood is just a warm, salty solution with relatively poor O2 solubility

primary strategies for regulating pH (acid-base balance)

1. buffering 2. changes in ventilation rate to void (or conserve) CO2 3. excretion of H+ or HCO3- ions via the kidneys/gills

coping with environmental hypoxia and anoxia (and hypercapnia) strategies (acclimations) for coping with environmental hypoxia/anoxia

1. increased reliance on anaerobic metabolism 2. hypometabolism (metabolic depression) 3. tolerance to prolonged hypoxia/anoxia via production of antioxidant enzymes 4. ectotherms may undergo 'hypoxia-induced behavioral hypothermia (HIBH)' (a form of behavioral thermoregulation) to reduce metabolic rates during hypoxia 5. some ectothermic vertebrates produce ethanol instead of lactate during anaerobic metabolism 6. increased use of respiratory binding pigments 7. adjust ventilation rates

Modes of feeding: small particles (glucose, aa, other small forms of DOM or dissolved organic matter)

1. passive absorption (can occur in several simple phyla groups like aquatic invertebrates like comb jelly, endoparasites, several protozoans) 2. endocytosis (phagocytosis/pinocytosis) -phagocytosis taken up small particles of food -pinocytosis is taking in water not food but similar process not just bacteria, but many marine inverts can directly uptake DOM 3. filter feeding (suspension feeding) usually phytoplankton or zooplankton (food capture for aquatic organism) (aka aquatic invertebrate) -mucous net (worms) -setae -ciliary feeding (when water taken in body for respiratory and food and filtered through cilia to get food and air) -cirri/setae (projections that are associated with the feet, trap food as filter through the water) mammals and birds filter feed too -whales and birds (flamingos) some bony fish and cartilaginous fish use specialized gill rakers to eat suspension feeding -cartilaginous fish use different appendages

what causes changes in body pH

1. respiratory acidosis/alkalosis - due to altered ventilation (changes amount of CO2 in the blood ) 2. metabolic acidosis/alkalosis - change in pH without change in CO2 3. diet 4. environmental changes in pH 5. temperature

1. respiratory acidosis (or alkalosis)

=disturbances in pH due to changes in the rate of CO2 elimination by the lungs or gills ... (relative to rate of CO2 production in tissues) in aqueous solutions: CO2 + H2O -> H2CO3 -> H+ + HCO3- (-> H+ + CO3 2-) -H+ decreases pH CO2 and water make carbonic acid which breaks down into protons and bicarbonate Hydrogens lead to change a pH CO2 acts like a weak acid (proton donor) carbon dioxide equalibrium curve shows you how much CO2 is dissolved in the blood as partial pressure changes (concentration of CO2 relative to pp) -higher overall concentration of CO2 in blood because travels as other things is the curve Do the following cause an acidosis or alkalosis? -Panting: decrease CO2 by releasing CO2 through ventilation (will give you an alkalization) -breath holding: Increase CO2 because its not being released leading to acidification (pH decreases) -activity: tissues respiring more, which increases CO2 producing but leads to hyperventilation that voids CO2 faster than you make it. Leads to decline in CO2 and alkalization

2. metabolic acidosis (or alkalosis)

=disturbances in pH that result from changes in blood level of H+ or HCO3- without changes in CO2 (as a result of metabolism or kidney/gill function) -changes in levels of H+ or HCO3- without changes in CO2 for example: -anaerobic metabolism (glycolysis) -vomiting/diarrhea -kidney/gill impairment glycolysis glucose turned into pyruvate in absence of oxygen = anaerobic and lactate dehydrogenase will produce lactate which produces additional H+ which lowers overall pH in the absence of oxygen pyruvate gets converted to lactic acid (=anaerobic metabolism) ... leads to a decrease in pH

nucleic acids

ATCG make up DNA and RNA not important from a dietary perspective can synthesize all of them ourselves

nutritional requirements vary widely

Based on? -endotherm vs Ectotherm endotherm metabolic rate is higher than ectotherm (means greater food requirements) -temperature lower metabolic rates at lower temperatures -adaptation to a specific habitat metabolic rate varies in response to depth of a fish -deeper that they are the lower the metabolic rate than a shallow fish at the same temp

Oxygen levels have varied dramatically over evolutionary time (continued)

Cambrian (10% oxygen) large increase in metazoans then with the evolution of land plants lead to a large increase in oxygen which is thought to have lead to the explosion of land animals

ecological modeling on ocean acidification

H+ in excess can dissolve existing shells change overtime and how atmospheric CO2 will change based on models ecological modeling predicts dramatic anthropogenic decreases in ocean pH and carbonate IS92a or I = less conservative model S650 or S = more conservative model bottom graphs: pH levels over latitudinal space (predicted overtime if CO2 rates occur) -pre-industrial time -pH in model S or model I -in these cases pH falls between 7.8 and 8.0 in year 2100 carbonate concentration at these pH levels in the ocean -historical carb concentrations -below is predicted concentrations under both models -aragonite and calcite concentrations (crystal forms of calcium carbonate -if ocean reaches a carbonate concetration lower than these saturation points is when you have dissolving away of calcium carbonate skeletons -in two predicted models there are points where you go below the saturation point (past argonite)

molecular level regulation of these acclimation responses animals use HIF to sense and respond to changes in oxygen

Hypoxia-inducible factor (HIF) exits in cell in normal conditions in 2 dimers (HIF-alpha and HIF-Beta) 1.when oxygen levels are normal HIF-Beta is always around in cell, and HIF-alpha gets tagged for destruction 2. under low oxygen levels, the protesome degradation is inhibited and HIF-alpha is not broken down 3. two forms dimerize (HIF-a and HIF-b) to produce HIF-1 4. hIF-1 acts like a transcription factor and enters the nucleus and bind to a hypoxia response element on the DNA. In this role they act as a transcription factor and will influence the transcription of genes that would be helpful for low oxygen levels the genes are on the next slide

mechanism of ocean acidification

Industrial processes lead to increase in pCO2 which equilibrates to oceans and PCO2 of ocean increases. Slowly breaks down in water to H+ and bicarb. More H+ in ocean fights certain molecules for other molecules in particular carbonate (important for shelled organisms). Carbonate combines with calcium to make calcium carb for a shell hydrogen binds carbonate to make bicarb -Carbonate is limiting in ocean -bind preferentially with H+ so animals have less to make hard shells

Atmospheric Composition

Nitrogen: 78.08% Oxygen: 20.95% Argon: 0.93% Carbon Dioxide: 0.03% water vapor: 0.4%

oxygen challenges and external respiration in terrestrial environments Lungs are internal gas exchange structures

On land, the concentration of air is higher, its less dense, the PO2 is pretty stable, BUT they really have to deal with desiccation (EWL) simple lung: lung of a pulmonate snail -carves out space around mantle tissue where its air filled space that can be drawn in or pushed out through muscular contraction true lung: gas filled spaces that are very branched. Start large and branch to smaller and smaller branches till at the very end have alveoli where all gas exchange occurs (thickness of membrane very thin) what is the advantage of lungs? Why the switch to lungs in the air? -way to conserve water loss -bad to have lungs in water because it would take a lot of energy to inhale /exhale water because of density and viscosity of water

Oxygen cascade

Oxygen travels through the body in a pattern of alternating convection and diffusion How oxygen travels from environment across gas exchange surfaces and into cells Movement of Oxygen from atmosphere all the way to mitochondria occurs through alternation of convective and diffusive flow 1. In the atmosphere the partial pressure of oxygen is 160, whereas in the alveoli its about 100 mmHg. (lower in lungs than environment because left over air their from breathing that has higher CO2/deleted of oxygen) 2. oxygen has gone from atmosphere to alveoli through convective flow of gas through the act of breathing. Inhaling produces a vacuum which sucks in gas in convective fluid flow form and brings oxygen all the way into the small spaces of the lungs. 3. oxygen partial pressure in alveoli to the partial pressure in the blood, the blood has slightly lower partial pressure (maybe 2 partial pressure units lower) -as long as there is a partial pressure gradient there, you will have movement of oxygen from the alveoli to the arteries through diffusion 4. If you compare the oxygen content from the arteries to the oxygen content of the capillaries themselves, tremendous drop of about 60 mmHg (or torr) in partial pressure -in order for oxygen to get from the arteries to the capillaries its another convective step thats just circulation of the blood. -theres a huge decrease because you have depletion of oxygen from the blood as it travels around the body -this is because by the time that you get to the capillaries and measure the oxygen there, its very low because oxygen is very rapidly being taken up by the cells 5. The partial pressure of oxygen in the intracellular region (ie inside a cell like a muscle cell) is much lower then the partial pressure of oxygen in the capillaries right around them because thats where the ozygen is being used -the movement of oxygen from the capillaries to the intracellular region is just diffusion across cell membranes 6. There is then another small diffusive step as you go from the intracellular region into the mitochondria (another small decrease in partial pressure). the only way this works is if there are partial pressure gradients to drive this movement of oxygen down its concentration gradient

Fick's Law of Diffusion (and some other properties of gas diffusion)

Rate of Diffusion (j) = k x A x ((P2 - P1)/D) -k: diffusion constant (depends on the solubility of gas and temp) -A: Area for gas exchange -P2-P1: difference in partial pressure of gas on either side of the barrier of diffusion (the bigger the difference the faster the rate of diffusion) -D: distance (thickness of barrier to diffusion) 1. Gases diffuse down partial pressure gradients 2. gases behave independently (only care about partial pressure of their own gas) 3. gases diffuse much more readily when they are in gas form compared to being in a aqueous solution -ie gases diffuse more quickly in air than in water 4. gas molecules that combine chemically with other molecules no longer contribute to the partial pressure 5. diffusion is a very fast way to travel over very short distances (distances less than about a millimeter)

Oxygen challenges and external respiration in aquatic environments: why is it hard to be aquatic

This gets difficult because ectotherms show an increase in metabolism as temp increase. At the same time oxygen content in the water is going down because solubility decreases as temp increases -decrease in O2 in water as temp increases because solubility decreases -one reason why aquatic life is difficult -gills help address this problem O2 consumption of an ectotherm increases as water temp increases but warm water holds less oxygen than cold water warm water is physiologically challenging for many ectotherms

1. buffering

a buffer is a solution that has a compound that acts for a sponge for H+ when its present primary buffers: -hemoglobin (RBC only) -amino acid buffers (about all proteins) (amino acids on proteins) -plasma proteins - in the ECF if pH rises, amino acids act as an acid and release H+. Releasing H+ to prevent a pH increase (alkalinization) If pH falls, amino acids act as a base and absorb H+. Sponges up excess H+ to prevent a pH drop (acidification) CO2 and O2 transport in the blood: what makes a molecule a good buffer is if the pKa of that buffer is at physiological pH (between 7 - 8.3, usually about 7.4) hence proteins are good buffers -buffers system around physiological pH How hemoglobin acts as a buffer: 1. say you are in a muscle tissue and are producing CO2 2. CO2 diffuses out of the cell into the epithelial (wall of the blood capillary - grey) and into the blood where it can diffuse straight into RBC 3. In RBC, CO2 breaks down into a H+ and a bicarbonate (HCO3-) which happens automatically where CO2 is dissolved. There is an enzyme that speeds up this reaction called carbonic anhydrase. RBC have high concentration of carbonic anhydrase (helps maintain CO2 gradient so that CO2 goes from tissues to blood) 4. in its broken down form the H+ now binds to a Imidazole group (functional side group on hemoglobin) and bound to hemoglobin it no longer lowers pH and will travel up to lungs in bound form. Hemoglobin acts as good buffer when not bound to oxygen (in tissues where oxygen is needed most oxygen has a tendency to fall off hemoglobin and delivered to where its needed in cells) (hemoglobin in tissues unbound and more able to bind H+ to the imadozole and buffer the blood) 5. in lungs, it starts binding oxygen, the H+ unbinds and recombine with bicarbonate and would form CO2 which you breathe out hemoglobin binds H+ and serves as a buffer 6. Bicarb leave cell through Cl/bicarb cotransporter and can remain freely dissolved in blood plasma 7. There are other buffering proteins in the blood plasma that are buffering H+ that are made from CO2 that never made their way into RBC. Carbonic anhydrase embedded in membrane that will breakdown CO2 and the H+ gets bound to a plasma protein 8. bicarb taken care of by the kidneys which doesnt directly change pH

what are some of the consequences of altered pH? case study: ocean acidification

a global climate change issue pH in the ocean is slowly decreasing as a result of high CO2 in air due to fossil fuel combustion (8.2 to 8.1 happen near more temporate areas) estimated change in ocean pH since pre-industrial period (1700s) long term data that shows acidification in ocean linked to atmospheric CO2 the graph shows the correlation between rising levels of CO2 in the atmosphere at Mauna Loa with rising CO2 levels in the nearby ocean at Station Aloha. As more CO2 accumulates in the ocean, the pH of the ocean decreases Co2 levels overtime from the 50s to 2019 pCO2 increase from 320 torr to 410 alters pCO2 levels of ocean and thus pH green = pCO2 levels in water -pCO2 mirrors increase in pCO2 in atmosphere (increasing) because of equilibration (ocean is a sink for CO2) - shows pH drop

pH effects the charge (ionization state) of a molecule (amino acid, weak acids, etc.)

an example is acetic acid dissociation pKa = 4.8 Low pH = undissociated form pKa = mix high pKa= dissociated which has negative charge as pH increases, free H+ Newly freed protons can bind with proteins that can change the charge of the protein and mess up its function as pH decreases, excess H+ (coming from somewhere else) are free to bond with buffering groups on acids/proteins, and this will change their charge (ionization state)

coping with environmental hypoxia and anoxia (and hypercapnia) what organisms are hypoxia tolerant?

anoxia tolerant ectothermic vertebrates 1. many invertebrates (inverts are ectotherm with lower metabolic rates so less sensitive to low oxygen) 2. several ectothermic vertebrates (fish and turtles) 3. some hibernating mammals 4. diving mammals 5. high altitude mammals and fliers temp versus anoxia survival time -for normal vertebrates at low temp can do maybe 30 min, but at higher temps more like 9 min (shorter time at high temp because respiration/metabolic rates increase as temp increase because enzyme activity faster when warm -anoxia-tolerant invertes can handle low oxygen for long periods of time (turtles, carp, goby)

oxygen challenges and external respiration in terrestrial environments some terrestrial animals can also breathe through their skin

anurans (frogs) lungless salamanders (family plethodonidae) earthworms slugs

relationship between [O2] and pH in an estuarine body of water

as you become hypoxic the pH declines -decline in pH isnt a consequence of oxygen (not direct) but a functional link because low oxygen leads to an increase of CO2 in the water because of the increased ventilation rate, which leads to a decrease in pH organisms consume O2, which reduces [O2] (hypoxia) and increase [CO2] (hypercapnia). This leads to a drop in pH (acidification). (oxygen itself does not directly change pH)

nutritional requirements vary widely

based on what? body mass (small has higher mass specific metabolic rate compared to elepant, metabolic scaling) reproductive status -growing eggs or placental organsism may have greater nutritonal needs, or more minerals

modes of feeding: Liquids (fluid feeding)

blood eaters nectar drinkers milk (crop milk can be made by some birds) sap eaters

Oxygen transport in the body

blood is a warm salty solution that isn't very good at holding oxygen, therefore we have respiratory binding molecules that bind to oxygen (binding keeps partial pressure low which helps maintain diffusion of oxygen into the blood) repiratory binding pigaments (RBP) -for when dissolution isnt enough -example: Hemoglobin (Hb) -hemoglobin is most common of RBP (only one in vertebrates) -iron molecule in the middle of a heme monomer can bind oxygen -this means that one hemoglobin molecule can bind 4 oxygen molecules There are 4 RBP -hemoglobin (typically found in the cells) -hemocyanin (in arthropods and molluscs, copper based, solubilized in solution, vary in the number of oxygen binding sites that they can have some may have one but others can have dozen of binding sites on one molecule) -chlorocruorin (marine worms, iron based, found in plasma/solution, dont have heme group, binds directly to proteins and found in cells) -hemerythrin all 4 evolved independently oxygen bound doesnt contribute to overall partial pressure why do animals need respiratory binding pigments? -because oxygen doesnt solubilize well in the blood so RBP helps increase the amount of oxygen stuffed into the blood O2 bound to a RBP does not contribute to the Po2

Oxygen challenges and external respiration in aquatic environments: Respiration in water versus air

breathing in water is harder then breathing in air because: 1. concentration of a gas in the air is much higher than water at the same partial pressure -table shows that concentration is almost 30 fold lower in O2 in water 2. water is much more dense and viscous than air -ex: density of water at 20C is 800 times the density of air -ex: viscosity of water at 40C is 35 times higher than air, and at 0C is 100 time higher than air

what are the consequences of altered pH on a molecular level?

changes in pH can change the charge of a protein changing a charge can disrupt the effects of the protein -enzymatic function and conformation

what are the consequences of altered pH on a molecular level?

changes in pH can change the charge of a protein too... and this disrupts function Histidine in the ER = 7.2 in the golgi = 6.5 PIC ER no charge in golgi more acidic and added H+ which changed the charge to + messing with a charge messes with: -enzyme activity/function and subunit aggregation (messes with weak bonds that create alpha and beta helices which mess with protein conformation) -membrane characteristics -cell osmolarity messes with charge or ionization states

effects of ocean acidification on sensory perception: fish olfaction

clown fish (juvenile) in choice chamber placed in chamber where odors are being pumped through on either side -control odor (seawater) -treatment odor (positive odor (move towards), negative odor (move away), neutral odor) -looked to see how frequently did they go to the side of the chamber where the treatment was at methods: percent of time spent on treatment side of chamber control: 8.15 pH spent 50% in wither chamber low pH: spent about half time in either chamber xantho (positive settlement cue (should be atracted) -should goes toward -control shows 90% animal went into chamber with that smell -pH decrease fish had significantly less fish go into that chamber malaluca (oil and avoided) -negative settlement cue -in control, no when into that chamber with that smell -in lower pH, around 80% of the time animals are in this chamber grass (neutral cue): -control is 50% -increase in low pH ananomae (positive cue) -control spends v large percent of time -low pH show drop in time they spend there

why do animals need to eat?

consume chemical energy in the forms of lipids, carbohydrates, proteins -digested forms absorbed into body to generate ATP to do work (3 forms of physiological work): 1. biosynthesis -process of growing molecules of your body (proteins, bones, blood, etc and products that get exported away like fur feathers during molt, gametes, mucus, milk) -either accumulate or get exported 2. maintenance -blood pressure -protein synthesis -electrochemical potential 3. generation of external work (ie locomotion/movement) -mechanical energy in all of these processes, all envolve enzymes and reactions -every energy transformations are inefficient to some degree ie some heat produced as byproduct -heat released by physiological work -means cant continuously recycle food because some of that energy eventually gets dissipated into heat which heat cant be used to do physiological work -energy being released in fecal product, chemical energy that gets exported, and mechanical energy that gets converted to heat so animals need to eat to power these processes

oxygen challenges and external respiration in terrestrial environments largest insects

current megaloprepus coerulatus giant damselfly (wingspan 15-20 cm) greates wingspan of any living damselfly/dragonfly ancestral (much larger) meganeura sp. giant dragonfly (wingspan 75cm) from carboniferous/Permian -oxygen had a spike in these times -thought that the increase is what allowed for the evolution of large insects because tracheal system is diffusion based, so increased movement oxygen through system

7. adjust ventilation rates

dashed line is normoxia -heart rate pretty level heart rate increases in hypoxia which increases their ventilation rate exposed to hypoxia they increase heart rate and ventilation rate universal across aquatic and terrestrial organisms -when oxygen levels are low your breathing rate increases

oxygen challenges and external respiration in shoreline/intertidal environments air breathing crabs continued

data from 5 species of terrestrial crabs show relative oxygen consumption rates for these species in both air and water range from very terrestrial to more semi aquatic take home of graph: the more terrestrial crabs consume more air than less terrestrial crabs -probably lung containing crabs fairly equal contributions of oxygen consumption when in air or water for the more aquatic crabs

adaptations to high altitude hypoxia - case study: bar-headed geese migration

during high altitude flight: -hyperventilate -breathe with very deep breathes -and have... specialized adaptations: -Hb with very high affinity for O2 -mitochondria aggregate near capillaries -and? ... findings of the group exercise

Oxygen challenges and external respiration in aquatic environments: insects and anthropods how aquatic insects/arthropod breathe

even many aquatic insects have 'gills' -tracheal gills -gill tufts -rectal gills -really just extension of the cuticle (where its very thin and very permeable) some insects use a 'spiracular snorkel' aka 'butt snorkel' some insects and arthropods breathe from underwater air bubbles (or plastrons- thin bubble in ventral surface) -use oxygen in bubble which drops pp and then oxygen goes down its concentration gradient into the bubble so it kind of replenished the oxygen in the bubble

adaptations to high altitude hypoxia in humans (case study)

evolved ways to deal with low oxygen in human populations two populations of native highlanders (Tibetan population and an Andean population) separate pops of humans that live at high altitudes (around 4000 m) some of the adaptive responses to high altitude low oxygen environments and how the adaptive responses arent the same Left: resting ventilation (breathing rate) and hypoxic ventilation -Tibetan population has higher ventilation rate -evolved baseline higher breathing levels even at rest compared to Andean and lowland people Right: hemoglobin concentrations and oxygen saturation of the blood -Andean show increase in hemoglobin concentration and overall oxygen saturation in the blood also both have Hb with higher binding affinities for O2

ocean acidification on seashells

excess H+ cause problems in other ways: 1. carbonate molecules in ocean are limiting in the ocean and H+ plays tug-o-war with carb to steal away from organisms that use them as shells 2. can start to dissolve away shells that are already existing 3. H+ entering cells of organisms and have to spend energy to kick them out, which E is diverted away from growth, immune function , ect which lowers fitness 8.25 preindustrial to 8.14 current 30% increase in H+ in ocean

oxygen challenges and external respiration in shoreline/intertidal environments make use of temporary oxygen storage

exosomatic water -pools of water that you can bring into your body but really into your shell -bathe gills in water that way burrows -built so there are caverns that collect air even with water covering it -can breathe air even when submerged

ocean acidification will lead to shell dissolution in marine organisms

experimental effects of change concentration of CO2 on organism shell -swimming snail -sub arctic species -kept in water that was under aragonite saturation point (48 h) effect: all show rough edges/pitch/edgings levels of carbonate in water below argonite can cause sonsequences to shell formation

modes of feeding: detritivores (deposit feeders)

feed on dead and decomposing organic matter ingest sediment, digest organic matter, then excrete the sediment millipedes woodlice dung flies slugs earth worms sea star/cucumber scavengers arent really considered detritivores

animals use HIF to sense and response to changes in oxygen

genes are genes useful during low oxygen VEGF: increase or promotes capillary growth PDGF-Beta: cell growth and division TGF-alpha: cell proliferation and differentiation (useful for decreasing size of muscle cell) EPO: stimulator for red blood cell production

Oxygen challenges and external respiration in aquatic environments: respiration in water versus air

geting air in water is harder... -concentration od O2 is 30x higher in air than in water -the density and viscousity are way higher which makes it harder of oxygen to diffuse through those substances (means high diffusion constants for air than water meaning air diffuses 9000 times better in air than in water) in order to get 1 L of O2 when in water, you have to process 30 L of water whereas in air you only have to process 1L of air what are the consequences of these differences in physical properties on respiration? Is it harder to respire in air or water? makes respiration difficult in water compared to air

6. increased use of respiratory binding pigments

hemolymph metabolic variables of a shrimp hemocyanin (RBP) under hypoxia significantly increases which shows the longer under hypoxia the more RBP glucose decreases and lactate increases because of anaerobic respiration (glucose supports anaerobic respiration) seen even in terrestrial organisms

how does environment influence feeding mode? terrestrial

herbivory very challenging due to cellulose (very hard to digest) -requires specialized hard mouthparts (chitinous radula, teeth, or cuticular mouthparts) -requires specialized gut structure and microbial symbiont communities (in both insects and vertebrates) -complex coevolutions have occurred between plants and herbivores (led to increase diversity)

1. increased reliance on anaerobic metabolism

how hypoxia exposure influences lactation, oxygen consumption, and oxygen levels in the chamber Chinese mitten crab dashed line if recovery period switch to anaerobic respiration because lactate is a product of anaerobic respiration -increasing lactate over time indicates they switched to anaerobic respiration Oxygen consumption is decreasing because anaerobic respiration is increasing (aerobic respiration is decreasing) succinate, alanopine, octopine are also end products of anaerobic respiration (anaerobiosis) oxygen debt required to get things back to normal after anaerobic respiration (in recovery for MO2)

hypoxia/anoxia

hypoxia (less than 2 mg of oxygen per L anoxia (less than 0.5 mgO2/L) normoxia (6-8 mg zo2/L)

ocean acidification impairs the ability of fish to detect predator noises how does ocean aicidifcation affect fish hearing?

impacts of OA of elements of sensory perception (hearing) methods: clown fish in closed tank within larger tank and theres a speaker -plays sounds that are all predatory (move away) data: proportion of time that the fish spent at the speaker end for each of the different PCO2 levels -390 control, spends about 30% of time at end where predatory sound is (less than 50% of time, means avoiding sound) -in increased PCO2 they all spend over 50% of the time by the speaker end relative to the control (the letter b indicates they are all significantly different from a) seems that OA impairs ability to detect predatory noises controversial because could effect something else thats not auditory ability

Oxygen challenges and external respiration in aquatic environments: counter-current flow in lamellar gills Very helpful for dealing with getting oxygen in aquatic environments major way larger vertebrate ectotherms are able to get enough oxygen

important to extract as much oxygen from the water when the organism is bigger and has higher activity levels -can do this with counter current flow There is O2 poor blood that goes to the lamelle, and travels through the lamelle (through a vessel), and then exits and as it exits its oxygen rich as it goes back to the body -the reason it is oxygen rich is because water is simultaneously flowing in the opposite direction of the blood as it flows through the lamelle -as they are in the lamelle and flowing in opposite directions, you have maximal exchange of oxygen from the water to the blood in the lamelle (opposite direction maximizes the oxygen extracted) take home: counter-current flow arrangment maximizes oxygen extraction from the water

3. excretion of H+ or HCO3- ions vis kidneys/gills

in general, pH is maintained (in the face of small, continual production of acid via metabolism and diet) by excreting H+ ions and conserving HCO3- via the kidneys or gills (due to slight increase in acid through metabolism and diet) The kidneys regulate pH dealing with acidosis by varying: 1. excretion of H+ in the urine -reduce [H+] and causes pH to increase 2. Reabsorption of HCO3- into the ECF (from the blood into the body) -bicarbonate acts as a buffer in the blood and causes pH to increase during acidosis the kidneys do whats in pic one mechanism same in the gills 1. epithelial lining of kidney (yellow is urine and purple/red is ECF). In the cells there is CO2 being produced from metabolism thats broken into H+ and bicarbonate. This reaction is facilitated by carbonic anhydrase. 2. The hydrogen ions produced have to be excreted through a transport molecule out of body into urine 3. cells (at least in gills) responsible for excreting ammonia or ammonium thats a waste product. 4. bicarb reabsorbed into the blood through another transport molecule -H+ gets out by two proteins -one is a V-type Hydrogen ATPase (hydrolyzes ATP to get energy to push H+ outside cell if working against a concentration gradient) -another is Na-H counter-transporter (driving source of H out is the movement of sodium inward because moving along its gradient where Na is less abundant in cells due to the Na/K pump 5. bicarb transporters -chloride bicarb counter transporter that brings 1 bicarb out for 1 chloride in (not a concentration gradient but electroneutral movement) -sodium-bicarb cotransporter (moves Na and bicarb into the blood

3. diet

ingestion of: -meat generally results in net intake of acid -plants generally results in net intake of base diet generally results in a net accumulation of H+

carbohydrates

keep in body in very low abundance we dont really store many carbs in most animals important for: 1. energy storage -in plants the energy storage form is starch -in animals it is glycogen -these are both just glucose polymers 2. important in some organisms for structural support -mainly in arthropods which use chiton (insects, spiders, crustaceans) -also cellulose (structural in plants) major forms of carbs: monosaccharids (glucose, fructose, alactose) disaccarides ( sucrose, maltose, lactose) major dietary forms sugars starches cellulose

oxygen challenges and external respiration in shoreline/intertidal environments air breathing land crabs

land crabs have wide spectrum of how they obtain oxygen in the air some still use gills that they must keep wet (water diffusion gills) - stuck near water others use a specialized branchiostegal lung (or abdominal lung) which breathes air directly (air perfusion lungs) - no gills at all there are species that fall along the spectrum between these kinds of crabs (one has gills and lungs)

4. ectotherms may undergo 'hypoxia-induced behavioral hypothermia (HIBH)' (a form of behavioral thermoregulation) to reduce metabolic rates during hypoxia

largely used in ectotherms When air is less saturated with oxygen they will choose a lower overall body temp to reduce metabolic rate lower body temp with lower concentrations of oxygen in the air intentional decrease in body temp to lower body rate reduces the metabolism

oxygen challenges and external respiration in shoreline/intertidal environments

like gooseneck baranacles (above) acorn barnacles are also good at oxygen consumption in air because of pneumostome formation -this is where in water they close their shells almost completely except for a tiny hole (theres also a bubble) -there they allow gases to diffuse in and out of a mantle inside the cavity and can oxygenate the gills without much desiccation risk gaping opening a closing shell -aimed at bringing oxygen into the body cutaneous respiration these are not the only ways that intertidal animals breath in air (go to next slide)

2. hypometabolism (metabolic depression)

looking at the percent air saturations effect on metabolic rate as air saturation decreases (hypoxia), metabolic rate decreases (metabolic depression) because decreases oxygen demands animals especially aquatic invertebrates

the effects of ocean acidification on calcification vary between phyla

low pH on shell formation not consistant between phyla -coral reefs degrade at low pH -however lobster and crab show higher grow/calcification -reasons not completely understood

5. some ectothermic vertebrates produce ethanol instead of lactate during anaerobic metabolism

metabolite concentrations in a fish under different oxygen conditions glycogen source for anaerobic respiration -supports anaerobic metabolism from initial anoxia to 6 hours later it shows a decrease in glycogen because they used it to do anaerobic metabolism the other ones are byproducts of anaerobic metabolism showing that anaerobic respiration is occurring -significantly the end-products are lactate and ethanol -few vertebrates make ethanol in anaerobic respiration -some will produce both ethanol and lactate prevents pH issues that come from prolonged lactate accumulation because lactate acidifies the body fluids but ethanol does not

jargon and their relationships

nutritional needs: these depend in the animals evolved synthetic abilities. When synthetic abilities are great, fewer compounds need to be ingested -just substances that serve as sources as metabolic energy -used as a source of growth, repair, and production of gametes feeding: on materials that potentially can meet nutrient needs. (the animals evolved feeding apparatus and feeding behavior determine the specific foods ingested) -process of selection, acquiring, eating digestive breakdown: of ingested substances by enzymes the animal synthesizes. (different animals have evolved different suites of digestive enzymes) fermentative breakdown: of ingested substances by microbial symbionts. (different animals have evolved different relationships with fermenting microbes) absorption: of products of digestion and fermentation, often by specific transporter proteins the animal synthesizes. (different animals have evolved different suites of transporters -transport of breakdown poductions into blood across gut nutrients delivered: to animal's cells negative feedback: ideally the process of feeding, digestion, microbial fermentation, and absorption meet (or at least reduce) nutrient needs

the effects of ocean acidification broadly vary by phyla

ocean acidification on physical properties across phyla -survival -calcification -growth -photosynthesis what is the overall effect size of ocean acidification on those processes across lots of organisms (calcification organisms and none calcifying organisms) -results vary based phylogeny -growth decline in calcareous algae and corals, but no sig growth in rest of groups -some no calcifying animals show increase growth rate in calcifying conditions significant reduction in growth rates overall effects on calcification -decline in most groups, but only significant in corals but sig increase in crustaceans -effect varies overall survival -significant decline, but not in groups independently -decline in photosynthesis in calcareous algae

adaptation to hypoxia in diving mammals

one best example of mammal for dealing with hypoxia bottom left: change in heart rate over time during a dive in a seal. Shows decline in heart rate the longer that they are diving (called bradycardia) -longer the dive the lower the heart rate because overall metabolic rate declines Top right: -oxygen concentration and lactic acid concentration in muscle and blood -over the length of a dive, oxygen concentration in the muscle depletes rapidly, whereas relative concentrations of oxygen in the arterial blood remains higher -same is true for lactate -great accumulation of lactate in muscles as anaerobic metabolism is occurring but arterial blood has low concentrations of lactate -indicates that aerobic metabolism is still happening in areas being served by the arterial blood, so brain, heart, lungs -do this through peripheral vasoconstriction (block blood flow to the brain, not much to viscera, skeletal muscles, limbs -restrict blood flow to brain heart lungs and block blood flow to muscle groups and extremities lower heart rate is suffiecient to supply blood to less of the body this means that less blood from the heart is required to service a now smaller circulatory system, and so see a reduced heart rate and decrease oxygen demand

Oxygen transport in the blood

only molecular O2 contributes to the partial pressure, bound O2 (to Hb) does not graph shows relationship between partial pressure in a solution and the concentration of oxygen -if no RBP and look at dissolved oxygen concentration in solution, will see very small increase in concentration of oxygen with increase in partial pressure because blood is crummy medium for oxygen (warm salty low solubility) -introduce RBP (dissolve/bound oxygen) shows concentration of oxygen is way higher at any partial pressure -shows RBP make oxygen concentration 20 fold higher in alveoli (100 kPa) oxygen equilibrium curve (total O2) = dissolved + Hb-O2

coping with environmental hypoxia and anoxia (and hypercapnia)

osmoconformers vs oxyregulators similar but different to these terms. You dont look that the oxygen level in the body compared to the oxygen level in the environment you look at the relationship between the partial pressure of the oxygen in the environment and the oxygen consumption rate -oxycomformer will match oxygen consumption rate to the oxygen availability -most animals oxyregulate over some wide range and then at a critical pp they start to conform (ie metabolic rate drops) generally range of pp where they regulate oxygen consump, then at some critical pp they switch to regulate (called Pcrit)

Oxygen challenges and external respiration in aquatic environments: how do air breathing fishes breathe?

over 400 species of fishes breathe air (mostly FW fish) -lungfish -some catfish -electric eels -gourami/betta fish -mudskipper most retain functional gills and are dual breathers (breathe air only when O2 is scarce in water) rarely fish are obligate air-breathers (eg electric eels, most lungfish) -typically have specialized lung structure in most cases, the specialize 'lung' (or air breathing organ) may be derived from the buccal cavity, opercular cavity, swim bladder, stomach, intestines or foregut. Fish inflate air breathing organ by buccal pumping

oxygen challenges and external respiration in shoreline/intertidal environments oxygen consumption rates in water versus air for intertidal organisms

oxygen consumption rates for a bunch of different intertidal organisms, which shows that there is a lot of variability in the relative amount of oxygen consumption in these invertebrates when they are in air (some can maintain oxygen consumption rates in air/water, some have better oxygen consumption rates in air versus water and some are opposite) -gooseneck barnacle good at oxygen consumption in air because of cutaneous respiration (permeability of integument) most animals become anaerobic when emersed; a few can still aerobically respire...how?

coping with environmental hypoxia and anoxia (and hypercapnia)

oxygen consumption rates for a shrimp Litopenaeus vannamei when in a sealed chamber of various oxygen levels demonstrates that over a wide range of oxygen levels they oxyregulate (150-20) at 20 they oxyconform hypoxia tolerant or sensitive species? They seem hypoxia tolerant Pcrit tells you about their hypoxia sensativity -the lower the Pcrit the more tolerant they are to hypoxia range of Pcrit for organisms in pic

oxygen challenges and external respiration in shoreline/intertidal environments some intertidal arthropods in anoxic bottom sludge concentrate respiratory pigments

oxygen low in these sludges so they have very high concentrations of hemoglobin or other RBP "bloodworm" = chironomid midge (fly) larva

what is pH

pH = -Log10 [H+] pure water = 7.0 what pH is considered 'normal' for an organism (ie blood)? 7 - 8.3 seawater = 8.1 (present day) ... 8.2 preindustrial revolution

acid dissociation constant (pKa)

pKa = pH where the acid exists half in its undissociated form and half dissociated (pKa varies a lot between acids and indicates the strength of the acid) pH higher = more dissociated pH lower = more undissociated where weak acid lives half way between conjugated and unconjugated form (HA = H+) -acidic pH = more H+ (could come from CO2 breakdown, or H from anaerobic metabolism) -excess H+ pushed more towards undissociated form (conjugated) because of La chatellier -effect of pH on charge of weak acids matter low pH -los H and have relative negative Charge (change in charge aka change in ionization state)

modes of feeding: toxins

paralyze prey to capture

Partial Pressure of a gas (in aqueous solution)

partial pressure of a gas in aqueous solution is equal to the partial pressure of that gas in the air with which the solution is at equilibrium (diffuse to create equal compositions = dynamic equilibrium) increase partial pressure leads to a gradient that forces molecules into solution, and over time this will reach an equilibrium state (PIC) The concentration of a gas in solution is not the same as the partial pressure -concentration is proportional to partial pressure Henrys law just states that the concentration of a gas in a liquid is proportional to its partial pressure (not the same because not all gases have same solubility in the solution) Henry's Law: Cx = A* Px -Cx: Concentration of gas x -A: Absorption coefficient (measure of solubility) -Px: partial pressure of gas x Different gases have different solubilities in an aqueous solution -oxygen: 34.1 mL O2 per L H2O -Nitrogen: 16.9 mL per L H2O -CO2: 1019 mL CO2 per L H2O (solubility of CO2 way higher than oxygen at a standard temp and pressure) solubility at 15C and 1 atm partial pressure concentration of oxygen at the same partial pressure as CO2, the concentration of oxygen will be lower because it is more soluble in solution

how does environment influence feeding mode? Marine

pelagic: (water-column) -filter-feeding on phytoplankton (no real herbivores) -some macroalgal herbivory (eg sargassum seaweed) -prey directly on other nektonic or planktonic animals Benthic (sea-floor): -filter-feeding in shallow environments -deposit-feeders and scavengers at depth (food scarce) -symbioses -lots of micro/macroalgal herbivory in intertidal/shoreline community

oxygen challenges and external respiration in shoreline/intertidal environments (gills out of water lose SA for gas exchange because clump together) diel variability in oxygen at shorelines

physical problems of breathing in dual environments gills out of water lose SA for gas exchange because clump together lots of variation in oxygen graph: variation in temp, oxygen, co2 for temp -in a tidepool during air emersion (low tide) (temp high because smaller body of water and lots of sun) but during night temp stays around same because no solar radiation -submerged -shows lots of variation in temp for O2 -oxygen levels high during the day and very low at night because of photosynthesis during day and cellular respiration of aquatic animals at night make it low CO2: just proves same thing as above Other graph: PO2 levels from seawater and then interstitial water on boulder beach just below that seawater over different months -shows how oxygen varies in the sea versus how it varies in the interstitial fluid -interstitial has much lower oxygen and vary over course over the year

the effects of ocean acidification are worst for

physiological processes which are most greatly impacted by ocean acidifcation survival and calcification show greatest decrease to ocean acidification (small decrease in growth and reproduction)

Oxygen transport into the body: gas exchange surfaces/ respiratory membranes

places where oxygen and CO2 diffuse back and forth -skin (small animals with low metabolic rates) (blood vessels associate very tightly with the skin to facilitate movement of oxygen in and around body) -gills (gills act as evagination of membrane that are highly convoluted that increase SA where gas exchange can occur. Also blood vascular tightly associates with this area for gas exchage) -tracheal system (dont have capillaries, system serves as the capillaries but is gas filled, gas diffuses in and out and each tracheals makes way to most of the cells in the body and you have interstitial fluid around the tracheals where gas exchange is occurring) -lungs (internal invaginations, highly convoluted to increase surface area, internalized to decrease water loss, In all of thee examples, there is close association of blood with the gas exchange surface and that surface has to be less than 1 mm thick -diffusion of oxygen through tissues can meet O2 requirements over distances of only 1 mm or less -circulatory system helps transport gases more quickly through a (larger) animal -vertebrates have close circulatory system (all blood enclosed in vasculature) -open circulatory system (varying complexity) -blood = hemolympth -hemolymph can profuse around all the cells in the body but it doesn't actually have any oxygen -there are more complex structures with hearts and vessels but they open into open regions that are called blood sinuses animals with open blood circulatory system have a larger blood volume (around 30% of overall mass) -animals with closed system have blood volume about 8% overall body mass

proteins

proteins are the most important macromolecule (most abundant) about half of the organic material in humans are made of proteins important: (proteins make up) enzymes, muscles, structural proteins (collagen, keratin), receptors, venoms, hormone, neurotransmitters proteins are made up of a combo of the 20 amino acids -plants/algae can make all the aa -animals cant synthesize all of them -9 are called essential aa that we cannot synthesize that have to come from the diet

nutritional composition of a body

proteins: 12 Kg lipids: 10 Kg minerals: 4Kg nucleic acids: 2 Kg carbs: 1Kg water: 42kg

modes of feeding: large masses

seizing prey: jaws, beaks, teeth teeth in mammals can be different/differentiated for different foods -invertes dont have true teeth (radula)/undifferentiated (exception is some snakes) tentacle feeding specialized tongues

oxygen challenges and external respiration in shoreline/intertidal environments aerial respiration by gills in some intertidal molluscs (eg chitons)

some intertidal animals use their gills in air to breath possible to use gills as long as they are most data: -showing a chiton species and the changes in the partial pressure of O2 in the blood, and also the oxygen consumption rate for the period where emersed in seawater and when emersed in air and then reemeresed in seawater -How does the oxygen level vary between water and air for this species? It doesn't change much (means maintain stable amount of oxygen in their body when they are exposed to air) -how do they do this? means that they have to have some way of getting air into the body as they maintain metabolic activity. The do this for species like this by flattening their mantle girdle down onto the ground where they keep a pocket of moist air around the gills -some species raise girdle to expose gills even more to the air around them -MO2 (oxygen consumption drops slightly but not that much) ie still maintain a significant amount of oxygen consumption when they are in air

Case study: Antarctic Nototheniods (icefishes) lack hemoglobin (and myoglobin)

some species that lack hemoglobin (and some cases lack myoglobin) live in cold temps which cold temps increase solubility of oxygen (makes it so that they dont need hemoglobin to increase oxygen concentrations in the blood) have to compensate for not having hemoglobin though -one way in which they compensate for a slightly lower oxygen carrying capacity is they have heavily vascularized retinas (enables for oxygen to diffuse from the capillary to the eye to serve the energetic needs to the retina) -they also have smaller cells (this is to decrease the distance over which diffusion of oxygen needs to occur to get from the blood into the cells themselves -have larger hearts

5. Temperature changes the pH of neutral water

temperature changes the neutral point of pH neutral water pH drops as temp increases because it pushes the reaction from H2O to H+ and OH- -just shifts pH scale, not the amount of H+ or OH- -increased temp increases kinetic energy of water and it can break down more easily doesn't matter for humans or endotherms because they maintain a stable body temp ectotherms regulate blood pH to compensate for temp effects on proteins -pH in the organisms mirrors the pH of neutral water as temp increases -happens intentionally, adjust pH up or down because temp influences the charge of proteins (pH compensates for the effects of temp on proteins)

Partial Pressure of a gas (in air)

the partial pressure of a gas is individual pressure exerted by any individual gas in a gas mixture (proportional to concentration but not the same as concentration) In atmosphere: Oxygen: 159 mmHg Nitrogen: 593 mmHg Oxygen + Nitrogen: 752 mmHg Daltons Law: Ptot = P1+P2+P3+... Units: 1 atm = 101 kPa = 760 mmHg = 760 torr = 1013.25 mbar sea-level is 1 atm Px = Ptotal * Fx (or pv=nrt ... ideal gas law if you dont know the total composition) if you know the total atmospheric pressure and the pressure of the individual gas then you can figure out the portion that an individual gas exerts in a mixture (Ptot = 170 (atmosphere) = .21 x PO2 = 159mmHg) aqueous solution: partial pressure of a gas in aqueous solution is equal to the partial pressure of that gas in the air with which the solution is at equilibrium

3. tolerance to prolonged hypoxia/anoxia via production of antioxidant enzymes increasing antioxidant production

the top graph is looking at glutathione peroxidase expression and the bottom graph is looking at superoxide dismutase which are both antioxidants top shows oysters exposed to hypoxia environments had higher expression of Glutathione peroxidase gardner snakes in anoxic conditions (black bar) had higher superoxide dismutase up-regulating antioxidants antioxidants get ride of free radicals (ROS) -happen because of burst in metabolic activity that happens after hypoxia leads to a big increase in ROS production -reoxygenation phase -could be harmful to proteins/DNA so prepare self for the phase for when they are out of hypoxia

Oxygen levels have varied dramatically over evolutionary time

today O2 is stable at 21% at the beginning of time, there was no oxygen as time went on Oxygen levels increased then at the Carboniferous period oxygen rapidly increased (result of evolution of land plants which also lead to a large increase in eukaryotic land animals) then it stabilized out at about 21% Cambrian time period 540 mya where most body plans form (mainly aquatic) and another speciation event in carboniferous period

oxygen challenges and external respiration in terrestrial environments insect tracheal system terrestrial insects

tracheal system -system of tubes that enter the body through holes called spiracles (opening into tracheal system) -can open or close spiracles to prevent water entering/ get air in -tubes make way through entire body (and sometimes have air sacs to help move air around) -ending is tracheoles that dont have cuticles that allows gas exchange -until very end the entire system is gas filled until the end where there is a little fluid but otherwise completely air filled system for delivery of oxygen blood tends to not have role in the respiratory system -helps deliver nutrients/ does waste sorting instead

lipids

two main roles: 1. energy storage -TAG -triacyl glycerol 2. important component of cell membranes (intracellular and extracellular) major classes: fatty acids TAG (major E storage form) waxes phospholipids sterols

ocean acidification will lead to problems with shell formation in marine organisms

unicellular phytoplankton called coccolithophores calcium carbonate shells top have been held in levels in CO2 that are similar to historical times (beautiful intricate shells) bottom is high levels of CO2 (similar to year 2100), start to show signs of damage (pitch and etching)

2. changes in ventilation rate to void (or conserve) CO2

ventilation rates for acid-base regulation pH increase increase ventilation rate when acidotic because increases the amount of CO2 that you are exhaling which removes excess H+ from the blood (brings pH up) PCO2 increase increase ventilation rate to lower pH to void excess pCO2 Hypoxic increase ventilation is common effect of low oxygen which is an attempt to get more O2 to feed the tissues

vitamins and minerals

vitamins are organic compounds that must be obtained in small amounts in the diet -tend to be diverse in structure and function -either water soluble (thiamin, riboflavin) or water insoluble (vitamin A, D, E, K) -most function like cofactors for enzymes (non protein molecule required by enzyme for enzyme to function) minerals Zn, Cu, Mn, Fe, K, Ca also required in small amounts -difference s that they are chemical elements -often function as cofactors for enzymes picture: cofactor binds to enzyme and binding allows enzyme to apporipriately bind to substrate and convert it to product -without cofactor it doesn't bind at all or not as fast -one of the most common os magnesium (enzyme cofactor for ATPase molecules) -also important for redox reaction cofactors (NADHA/FADH) -also metaloproteins (iron or copper can function in hemoglobin or hemocynan organisms) -calcium is involved in bones and shell formation

current oxygen levels vary among areas on earth

ways in which oxygen varies n our planet sea level - 160 torr (21%) terrestrial - 21% O2 -decease O2 with altitude -variation in O2 in specialized microhabitats like burrows/ soil layers have lower oxygen layers (down to 10% oxygen) in aquatic environments -FW varies a little more because temp varies more -swaps/tidepools/ sludge can have v low oxygen -ocean is reasonable concentration of oxygen arounf 4.8 mL/L SW -variation where theres a particular depth (oxygen minimum layers) or deep sea or trenches

4. changes in environmental pH

when does an organism experience a change in environmental pH? -acid rain (where rainfall has high acidity) -ocean acidification -natural CO2 seeps (creates bubbles of CO2 which creates decrease of pH in that area) -environmental hypoxia also leads to reduced pH -red = hypoxic/anoxic dead zones -regions in the ocean in gulf of Mexico and on the pacific coast major responses in animals that are experience hypoxia -increase ventilation rate (water itself increases in pH while there is an alkalization in the blood) -switch to anaerobic metabolism (makes lactate which decrease pH of blood)