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
first step of ventilation
- bulk flow
- breathe in air and CO2 out
second step of ventilation
- O2 diffuses across respiratory surface and into blood
- CO2 diffuses out
third step of ventilation
- circulation by bulk flow
- O2 and CO2 transported by circulatory system to and away from cells
fourth step of ventilation
- diffusion between blood and cella
- O2 diffuses from blood into cells and CO2 diffuses out of cells into blood
humans breath uses what pressure
negative pressure
what does breathing involve?
- bulk flow between respiratory medium (air, water) and gas exchange surface (body surface/lungs/gills/etc)
- diffusion is too slow therefore we need ventilation
what is gas exchange
- diffusion between environment and ECF
- SA of gas exchange surface is proportional to mass and metabolic rate
- large animals needs specialized gas exchange structures
fick’s diffusion law
Rate = (D) (A) dc/dx
d= diffusion coefficient
A= area of diffusion
C= change in [solutes]
X= thickness
what is countercurrent exchange
- less O2 available so takes more energy
- fish opens mouth to take in water
- water moves through gills (while it moves through, O2 gets absorbed)
- O2 and blood goes in opposite directions
- mose efficent
- diffusion
what is crosscurrent exchange
- air moves in one direction
- takes 2 cycle to move 1 unit of air (like pipette)
- more air moves to sack when inhaling
what is uniform pool?
- bidirectional, multidirectional flow
- takes 1 cycle to move 1 unit of air
- less efficient
what is pH
measure of [H+]
How does pH affect proteins?
- alters charge, protein shape
- affects solubility, function and enzymatic activity
CO2 + H2O <-> H2CO3 (carbonic acid) <-> HCO3- + H+
- high CO2 shifts equation to right to generate more H+ AND HCO3-
What are some buffering systems
- maintains pH
- Pulmonary
- Renal
- chemical buffering
what is pulmonary buffering system
- ventilation and respiration (TAKES MINUTES)
- second buffering system
- regulates CO2
what is renal buffering system
- excretion/diffusion of HCO3- or H+ (HOURS TO DAYS)
- last buffering sustem
what is chemical buffering system
- controls blood plasma (fast)
- first buffering system
what does respiration do
- regulates blood lvls of carbonic acid
- CO2 generated in cells increases concentration in blood
- CO2 gets diffused into erythrocytes where it combines w/hemoglobin to form HCO3- and H+
what does excretion (circulatory system) do>
- body getting rid of waste through urine to restore homeostasis
what happens when pH decreases?
- brain stimulated
- Respiratory rate increases
- Blood CO2 levels decreases
- Blood H2CO3 decreases
- pH increases
what happens when pH increases
- stimulates brain
- Respiration rate decreases
- blood CO2 lvl increases
- Blood H2CO3 increases
- pH decreases
compare animal and plant nutrients
- plants make their own food via photosynthesis
- animals need proteins
( need methionine -> cannot make our own so we need to eat plants)
explain plant nutrients: hydroponics experiment
- grew plants in solution then removed one nutrient at a time and observed growth
- result: deduces essential elements are
~ necessary for growth/reproduction
~ cannot be substituted
~ play roles in metabolism
~ plant dies if it was taken away
what does soil contain
- mineral particles, compounds, ions, decomposing organics, water, air, organisms
describe clay
- large SA to V ratio
- (-) charged so holds water easily
- water hardens clay making it difficult for plants to grow
describe sand
- large particles so water and nutrients drain faster
what is humus
- decomposing organics (usually on very top layer of soil)
- holds water and nutrients well)
what is passive transport
- no metabolic energy
- substance moves down concentration or electrochemical gradient
- simple diffusion of water, O2, CO2
what is active transport
- meeds metabolic energy (ATP)
- moves AGAINST gradient
- transports proteins using energy
what are essential elements for plants
- 17 essential elements
- macro and micro nutrients
what consists of macronutrients
- C, H, O from air and water (not minerals)
- N, P, K, S, Ca, Mg = minerals (in soil)
what consists of micronutrients
- CU2+, Cl-, Ni2+
what is chlorosis
yellowing of plant tisseues due to lack of chlorophyll
what is soil solution
- combo of water and dissolved substances that coat soil particles + fills pores
- available for plant after gravity drainage
- water molecules attracted by (-)ve clay + humus particles
what are some mechanisms to increase uptake of water and nutrients
- root hairs
- mycorrhizae
what does root hairs do
- if increased SA, more water and minerals absorbed
- no cuticle or stomata so they can be sponge-like
- charged particles that require own channel or transporter
what does mycorrhizae do
- mostly phosphate
- symbiotic relationship between fungus and plant roots
- plant give C to fungus
- fungus increases soil nutrients to plant
what are some Nitrogen limitation
- can’t use bc lots are unread
- triple bond in N requires specific enzyme to break
what is the first step of nitrogen cycle
Nitrogen fixation
- converts atmospheric N2 into NH3 (AMMONIA) which dissolves to (AMMONIUM) NH4+
what is the second step of nitrogen cycle
ammonification
- breaks decaying organic N compounds into NH4+
what is the third step of nitrogen cycle
Nitrification oxidizes NH4+ to NO3-
what is the fourth step of nitrogen cycle
plant converts NO3- to NH4+ to assimilate N into organic compounds
how does minerals in soil enter plant?
- passively enter through roots along with water
- anions needs to be absorbed fast or else it will get washed away
what are some problems with N as fertilizer?
- causes eutrophication (grows algal blooms. once it dies it creates O2 taking bacteria)
- contributes to green house gases (N2O - nitrous oxide is worse than CO2)
describe the cation exchange
Mg2+, CA2+, K+ absorbed into (-)ve charged soil particles
- exchange replaces minerals w/H+ or carbonic acid
what happens in alkaline soil
anions leeched out easily
what happens in acidic soil>
cations leached out easily
what does short distance transport involve
- into and between cells
- to and from vascular tissues
what does long distance transport involve
- moves substances between roots and shoot parts
- 90% of water lost through transportation
what are 2 water transport ways
- apoplastic and symplastic pathways
what is a apoplastic pathway?
- water moves across outside membrane until it reaches endodermis (airport security)
What does the endodermis do
screens for impurities (only in apoplastic)
what is the symplastic pathway
- water goes through all cell layers Bia the plasmodesmata (connecting membrane between cells)
what is the nutrient movement?
- taken up from soil along with water
- both move in apoplast (passive uptake) and symplast (active uptake)
- endodermal cells = selective barrier
what is aquaporin
proteins allowing rapid movement of water through hydrophobic membrane core
what is water potential
potential energy of water (driving force)
what is the casparian strip
- root in endodermis forcing apoplectic water and nutrients into symplast
- ensures all water and solutes pass plasma membrane to enter vasculature
- restricts solutes from flowing back
- made of waxy substance
water potential equation
Ψ = Ψs (potential) + Ψp (pressure potential)
- Ψ of pure water = 0
- presence of solutes lowers water potential Ψs
what does the central vacuole do
- adjusts solute and water
- only in plants
- has tonoplast membrane that maintains turgor pressure
- high solutes = high pressure of system
- water always follows solutes
how does long distance travel work in xylem?
- cohesion-tension force
- root pressure
- stomata movement regulates loss of water by transpiration
cohesion-tension: root pressure
- (+) pressure in roots that forces xylem sap upwards
- occurs in high humidity or low light
- moves water short distance
- contributes to guttation
cohesion-tension: guttation
- when root pressure is strong enough to force water out of leaf openings
- water pushed up and out of veins
- only good in small plants
- in hot days, guard cells closed to prevent water loss
describe the pressure flow mechanism
- moving substances by bulk flow under pressure from source to sink
- based on water potential gradients
- load from source -> transport in sieve tube -> unload in sink
pressure flow mechanism steps
- more [surose] in sieve tube brings water potential down
- water from xylem enters sieve tube causing pressure to go up
- sap flows in bulk to sink (lower pressure)
- sucrose is unloaded into sink
- water goes back to xylem via osmosis
what’s transpiration
- evaporation of water through stomata pores
- cohesion-tension driven by transpiration
what is cohesion-tension
- h bonds of water help each other go up (cohesion)
- h bonds weakly attaches themselves to cell walls (adhesion)
-evaporation of one water molecule brings negative tension which creates negative pressure forcing another water molecule to go up
what is translocation
- long distance transport of substances via phloem (alive at maturity)
- multidirectional (xylem is unidirectional
what is phloem sap
- water and organic compounds moving through sieve tubes
- difference in pressure between source and sink regions drives flow)
what is a source
- region of plant where organic substances are LOADED into phloem
what is sink
- region of plant where organic substances are UNLOADED from phloem (mostly symplastic)
what is the phloem consist of?
- sieve tube and companion cell
- sieve tube can undergo partial cell death
- companion cell acts as side support that keeps sieve tube alive
- companion cell also converts simple sugars to complex sugars
how does CO2 and O2 get exchanged in plants?
through stomata
what is the stomata made of
- guard cells surround small pore (stomata)
stomata movement: transpiration-photosynthesis compromise
- balance of transpiration + gas exchange by opening/closing stomata as enviro changes
how is the stomata controlled?
- transported by K+ going in and out of cell
- stomata opens to photosynthesize (high blue light and low [CO2])
- Absicis acid (ABA)
How is transpiration regulated to prevent desiccation?
- cuticles limit water loss but prevents CO2 uptake
- Water always lost
what is abscisic acid (ABA)
- suppresses growth
- hormone signal for closure of stomata
open guard cell has what?
high K+
closed guard cell has what?
k+ needs to be pumped out (leading water to follow it and closing the guard cell)
what is Auxin
- promotes growth and elongation of cells
- governs response to light and gravity
- synthesized in shoot apical meristem and young stems + leaves
what is gibberellins
- stimulates growth + elongation of cells
- bolting: development of flowering stems
- fruit enlargement
what is cytokinins
- enhances growth and retard aging
what is ethylene
- gaseous hormone that regulates responses including senescence (cell stop growing)
what is Brassionosteriod
- regulates plant growth responses
what is Jasmonates
- regulates growth (also important for defence)
what is phototropism
- growth response to direction of light source
- blue light triggers auxin transport (elongation of cells
what is the acid-growth hypothesis
- where auxin pumps H+ out which activates the expansion to break cellulose
what is a hypersensitive response
- infected and uninfected cells around infection kills themselves to contain pathogen
- strengthens cell walls
- closes stomata
- selective plugging of xylem
what is systemic acquired response
- plant releasing signal to other plants telling that they were under attack so defend themselves
- this way other leaves don’t have a hypersensitive response
how does tannins defend plants
- when plants are attacked, tannins are increase which makes plant bitter making insect top eating them
what are perfect flowers
both stamen and carpel on same flower
(both sexes on same flower)
eg. corn
what are imperfect flowers
- stamen or carpel ( not both)
- one sex
what is fission
parent splitting into two bodies
what is budding
parent grows cells that branch off
what is fragmentation
parent breaks part of themselves off
what is parthenogenesis
baby develops from unfertilized egg
pros of asexual reproduction
- reproduce in isolation
- reproduce rapidly
cons of asexual reproduction
- less/no genetic diversity
what is dioecious
- 2 houses (individuals produce one type of gamete)
- dad houses sperm; mom houses egg
what is monoecious
both egg and sperm in same body
eg clownfish
pros of sexual repro
- genetic variability
- more complex
cons of sexual repro
- slow ( courtship)
- energetically costly (to produce gametes, find mates, parental care, vulnerability to predation)
what is direct development
baby looks like tiny version of parent
what is indirect development
baby does not look like parent
eg tadpoles
what happens during fertilization
sperm and egg fuse to form zygote
what happens during cleavage
- zygote divides to morula then blastula
what is the morula
beginnings of body plan (symmetry)
what is the animal pole
cell divides to become animal
what is vegetal pole
becomes nutrients (yolk)
what happens during gastrulation
formation of echo/meso/endoderm, gut, mouth/anus
what are the 6 mechanism of gastrulation
- mitosis
- cell movement (cell moves to new position)
- selective cell adhesion
- induction (one group not cells influences other cells
- determination (fate of tissues determinbed)
- differentiation
what is spermatogenesis
- production of sperm
- specialized to move and penetrate egg
what is oogenesis
- production of ovum
- stores nutrients for early stages of development
- has protective coating
what happens during early stage of development
- produce zygote
- cleavage, blastula, gastrula (formation of tissue layers)
- chordate neurulation
what happens during external fertilization
- broadcast spawning
- many small gametes (low parental care)
-usually in sessile or marine animals
what happens during internal fertilization
- male deposits sperm into female
what is the acrosomal reaction
- fast reaction
- once sperm gets through egg, releases this response to prevent other sperm form entering
what is the cortical reaction
- slow
- egg creates thick layer around itself completely blocking other sperm
endoderm turns into what
digestive system
mesoderm turns into what
muslcles nd blood
ectoderm turns into what
skin, nervous system
what are the steps of chordate neurulation
- notochord causes cells to thicken
- cells sink and forms closed tube
- edges fuse together closing the tube (spine)
- migrating beiral cress cells becomes face