final Flashcards
Pros of life in water
- high heat capacity = stable temp
- metabolic waste easily removed in h2o
- sound transmits well
- H2O supports body
- aquatic reproduction by broadcasting gametes into water to avoid drying out
cons of life in water
- density and viscosity costs locomotion and visual range
- limits metabolic rates (bc takes more energy to pull O2 from water)
comparing life in air vs life in water
AIR:
- low heat capacity = temp extremes
- low viscosity = air flows easily
- O2 diffuses faster in air
- less dense due to gravity
WATER:
- high heat capacity = stable temps
- universal solvent (H2O dissolves/transports molecules)
- high viscosity due to strong intermolecular bonds
- O2 needs to be dissolved (less O2)
- high density (pressure changes with depth)
what are some challenges on land?
- desiccation
- getting rid of toxic wastes while minimizing H2O loss
- breathing air
- sensory systems and structures
- protective coating or internal structure for gamete exchange
- structures supporting gravity
adaptations to avoid desiccation: mechanisms to reduce water loss
- skin and waxy cuticle
- behaviour (hunting at night)
- production of concentrated urine (loop of Henle)
what is loop of Henle?
- vertebrate kidney (U shaped)
- reabsorbs water and NaCl to produce highly concentrated urine
adaptations to avoid desiccation: mechanisms to replace water loss
- drink and eat moist foods
- metabolic water (water generated through process of metabolism)
adaptations to avoid desiccation: develop desiccation tolerance
- going into aestivation (dormancy)
- example = lungfish. during dry seasons they dig into mud and curl up. a protective cocoon mucus forms. stays in that state until H2O returns
adaptations to avoid desiccation: Parthenogenesis
- form of aesexual reproduction (low cost)
- occurs in unstressed, moist environments)
performance curve (describe what happens below 0 degrees and approaching 45 degrees)
- cell functions between 0 and 45 degrees
Below 0 degrees
- ice crystals;s destroy organelles and cell membranes
Approaching 45 degrees
- proteins and nucleic acids unfold and lose function
temperature extremes adaptations
- endothermy (produce own heat)
- sweat to cool down
- behaviour (hunting at night)
- freeze avoidance to lower freeze point
temperature extremes adaptations: freeze tolerance
- ice nucleating proteins ( organisms can control where ice crystals form to prevent ice from spreading through entire body)
- higher proportion of phospholipids
- lower metabolism
excretions of waste
- ammonia is toxic (usually aquatic animals)
- urea = less toxic and can be stored at higher temp (prevents water loss)
- uric acid = insoluble (white paste in bird poo)
how do they protect reproductive structures from desiccation?
- gametes are fertilized internally (which means they need to find mates)
- embryos protected by
- some animals have eggshells
- amniote vertebrates have membrane that encases and protects amniotic fluid that surrounds embryo
gas exchange to transport O2 and CO2: aquatic animals
- less O2 bc of high density and viscosity (takes more energy to move O2 across water surface)
- easier to get rid of CO2
gas exchange to transport O2 and CO2: gas exchange in air
- diffusion is 10 000 times faster than in water
- higher O2 content bc of low density + viscosity
- not easy to remove CO2
- must be covered by thin film of fluid
- has evaporative loss
gas exchange to transport O2 and CO2: internalized gas exchange
- inward, protected, moist structures
- higher SA
- reduces H2O loss
- example = tracheal sys. in insects
sensing in air: light
- radiant energy
- bigger eyes in air = better visual range
- bigger eyes in water = visual range not better
sensing in air: sound
- waves of pressure
- less compressible = faster
- more compressible = slower
- vertebrate ear translates air into fluid energy
sensing in air: smell and taste
- small molecules
- olfactory system in mosquitoes has hair like chemosensory structures on antennae. also uses pores to allow molecules to enter
Does SA;A increase or decrease as animals get larger?
- decreases
- support = area dependent
- mass = volume dependent
what is isometric scaling?
proportional scaling
what is allometric scaling?
- alloios = different
- disproportionate scaling
what is Kleiber’s Law?
- metabolic rate = (mass)^3/4
- smaller animals uses energy less efficiently
- bigger animals uses energy more efficiently
in allometric scaling, what does it mean when slope is greater than 1
- gets bigger
- example: skeleton has a slope higher than 1 so that means the skeleton got bigger as body size got bigger
in allometric scaling what does it mean when slope is less than 1
- gets smaller
- example: metabolic rate has a slope smaller than 1 so that means MR gets slower as body gets bigger
how does skeleton support the body?
- having skeletons = stronger limbs
- rib cage = thick and heavy to support lungs and organs
- articulated spine (spine being able to move) to support limbs, attachment points to strong pelvic + pectoral girdles
- mobile neck
how does stance support body?
- limbs positioned to support body system
- small animals = sprawling stance (ants)
- bigger animals = upright so that bones can support mass of body
compare locomotion on land vs water
LAND
- speed is limited by body mass
- larger body mass = slower
WATER
- having bigger body mass doesn’t matter bc water supports weight
(which is why whales can get so big)
what are some challenges on land?
- desiccation
- creating air (gas exchange)
- sensory systems (detecting light, sound, smell)
- gravity
- gemete protection
what is homeostasis?
- homeo= the same; stasis= standing or stopping
- to maintain steady internal enviro
- uses biochemical rxn to control it
what does “internalized” external cells have?
- rapid turnover rate
- lethal enviro to microbes
- secretions to protect gut lining
extracellular cells are connected through what?
homeostasis
what is osmoregulation?
- regulation of internal osmotic (salt/water/waste) environment
- regulated by bulk flow, diffusion, osmosis
what is bulk flow?
movement of liquid from area of high to low pressure (hydrostatic pressure )
what is diffusion?
solutes moving from area of high to low concentration
what is osmosis?
solute moving from low to high [solute] by crossing semipermeable membrane
what is hyperosmotic?
- lots of solutes
- high pressure = low potential
what is hypoosmotic?
- low solutes
- low pressure = high potential
what does water potential include?
osmotic potential, hydrostatic gravity, humidity
explain the steps of excretory organ (as mechanism for osmoregulation)
- Filtration (non-selective) filters out water, salt, ions, waste
- Secretion (selective) the wastes and solutes are secreted in tubule
- reabsorption (selective) reabsorbs salts, water, etc back to the capillary
what is excretion as a mechanism for osmoregulation?
the elimination of waste (that aids in controlling content of extracellular fluid (salt, water, pH)
factors of internal environment that are regulated by homeostasis
- temp
- concentration of water and NaCl
- volume + pressure of blood vessels
- concentration of waste chemicals
- concentration of O2 and CO2
- pH
- nutrient concentration for energy production by cells
what happens in a hypoosmotic enviro?
- cells swell
- low solutes and high water
what happens in isosmotic environment?
- balance. equilibrium of salt and water
what happens in hyper osmotic environment?
- cells shrink
- high solutes and low water
what does fresh water cause in plants?
- hydrostatic/ turgor pressure which prevents influx of water
- causes plant to be in hypotonic state
how does aquatic animals secrete ammonia (NH3)?
- diffuses ammonia into enviro (across body/gills)
- excretion in filtrate/urine
- ammonium (NH4+) and sodium exchange
How does terrestrial animals secrete ammonia (NH3)?
- Cannot use diffusion or ion exchange w/air
- only excretion in filtrate
- produces urea or uric acid
what is the first step of homeostasis by negative feedback?
- change in internal or external enviro to produce physiological variable (ex. low body temp)
what is the second step of homeostasis by negative feedback?
- change detected by specialized cells
what is the third step of homeostasis by negative feedback?
- receptor (sensor) sends info along afferent (sensory) pathway
what is the fourth step of homeostasis by negative feedback?
integrator (specialized cell) receive sensory info and determine if action is required
what is the fifth step of homeostasis by negative feedback?
info is sent along an efferent (motor) pathway
what is the sixth step of homeostasis by negative feedback?
the effector receives info and produce compensatory change in physiological variable affected by enviro change (shivering)
what is the seventh step of homeostasis by negative feedback?
physiological actions of effector returns condition to desired levels
what is osmoconformer strategies?
- adjusts cells and extracellular fluid to match enviro [Y]=[X]=[Z]
- MARINE ANIMALS
what is osmoregulatory strategies?
- adjusts extracellular fluid to match cells and protect it from internal enviro
[X]=[Y] does not equal [Z] - FRESHWATER FISH
what are some terrestrial challenges of water/salt ion loss and gain?
- water loss by dry enviro (water moving out
what are some aquatic challenges of water/salt ion loss and gain?
- marine animals = water loss (needs to limit urine and drink water ) (hyper osmotic)
- freshwater = water gain (needs to excrete large amount of diluted urine and drink little water) (hypoosmotic)
what is the terrestrial response to osmotic enviro?
- terrestrial = dry
- loss of water due to enviro so they need to consume/produce/conserve water
- limit salt intake
what is the marine response to osmotic enviro?
- hyper osmotic
- lose water and gains salt from enviro
- needs to eliminate salt (concentrated urine) and consume/produce/conserve water
- limit salt intake
what is the freshwater response to osmotic enviro?
- hyper osmotic
- gains water and loses salt
- eliminate water (dilute urine) and consume/conserve salt
- limit water intake
what is circulation?
bulk flow of fluid within body (water, solutes, nutrients, gases)
what is gas exchange
exchange of gases w/enviro
what is pH regulation
controlling [proton H+] of body fluids
how does circulation aid with transfer of solutes?
- via hormones, heat, gases, nutrients, etc
where does circulation happen in animals?
- in heterotrophs with digestive systems
- if they have high metabolic rates = rapid circulation
- cardiovascular sys= muscular pump + vessels
what is an open circulatory system
- pump moves hemolymph through sinuses in body tissues
- no distinction between hemolymph and interstitial fluid
- only pumps out
- not enclosed
what’s a closed circulatory system
- moves in closed circuit
- blood is operated from interstitial fluid
- small diameter blood vessels exchange gases, nutrients, waste etc
- one direction
what does extracellular fluid (ECF) contain?
- plasma (water, ions, proteins, nutrients, gas)
- Key ions = Na, K, Cl, HCO3, Ca, H
- Key proteins = globulins, albumin, fibrinogens
- key gases = O2, CO2
- erythrocytes
- leukocytes
- platelets
what are erythrocytes
- contains respiratory pigments like haemoglobin and hemocyanin
- increases capacity of fluid to carry O2 and CO2
what does arteries do
- carries fluid AWAY from heart
- controls blood distribution to body by controlling vessel diameter
- takes pressure waves from heat and dampens them so they’re not too intense
what does veins do
- carries fluid BACK to heart
- stores blood (easily expands)
- important for transportation, storage, exchange
what does the heart do
- muscular pump that uses energy to contract muscles
- maintains bulk flow of fluids in face of resistance (gravity)
what does capillaries do?
- exchange substances between blood + tissue (gas, fluids, solutes, nutrients, waste)
- promotes diffusion
- far from heart = high area = low velocity
what are single circuits
- 2 chambers
- one set of vessels
- limits metabolic rate (bc low pressure in systemic capillaries)
- lower efficiency
- mostly in fishes
what are double circuits
- 4 chambers
- 2 sets of vessels
- high BP from heart
- definitive split b/w oxygenated and deoxygenated blood
- most efficient
- birds and mammals
what are variable circuits
- 3 chambers
- no definitive split between oxygenated and deoxygenated blood (can mix)
- can shut iff circuit to lung capillaries
- variable efficiency
how do giraffes prevent hypertension?
- thick ventricle of heart w/o stiffening
- dense connective tissue in legs
why is gas exchange needed?
- kerb cycle and oxidative phosphorylation consumes O2 and releases CO2
- photosynthesis consumes CO2 and releases O2
- pH regulation uses CO2
how does ECF circulation help gas exchange?
- circulation moves ECF in animal (bulk flow) using muscular heat and blood vessels
- at the interface there is diffusion of capillaries
- needs small diameter