bio finals Flashcards
1
Q
difference in requirements of energy of between ectotherms and endotherms
A
endotherms require less energy than endotherms
2
Q
Do organisms have similar enery demands?
A
Yes
3
Q
Do organisms spend different amounts of energy to meet each demand?
A
Yes
4
Q
does surface area scale with mass like it does in a geometric shape?
A
absolutely
5
Q
how do large organisms increase surface area?
A
they have highl branced circulatory, respiratory, ad digestive systems. humans need 25x the skin surface area
6
Q
how does the size or mass affect the energy expenditure of organisms?
A
it influences the way they move, how often and what they eat
7
Q
how much energy does a large animal require?
A
it requires a higher absolute energy but less energy per gram
8
Q
relationship between how long the food stays in the digestive tract and food
A
how long food remains in the digestive tract is a phenotypic trait that responds to selective pressures in the environment. the longer it takes to digest food, the longer the retention time. ex. protein is easier to digest while carbohydrate and fats stays long in the digestive tract because it is harder to digest.
9
Q
relationship between length, area and volume
A
volume is proportional to the length cube nad surface are is proportional to the length squared
10
Q
relationship between the size of an organism and food
A
large organisms need more food than small organisms which means that large organisms will have a larger Ein (energy in) value per unit time.
11
Q
the realtionship between air intake, the volume of blood pumped in each heartbeat and the size
A
large organisms take in more air with each breath and pump a greater volume of blood in each heartbeat. they have a lower breathing and heart rate than small organisms
12
Q
the relationship between how often an organism eats and their size
A
larger organisms can eat more food at a given time than small animals. they also eat less often than small organisms relative to their body size
13
Q
the surface area of an organism
A
membrane/skin
14
Q
the volume of an organism
A
mass
15
Q
What are the energy demands of an organism?
A
Maintenance, growth, activity, reproduction
16
Q
what do the energy budget depends on?
A
it depends on size, activity and environment
17
Q
what id the definition of scaling?
A
the study of the effect of size/mass on anatomy/physiology
18
Q
what is a measure of evolutionary fitness?
A
it is the total amount and rate at which they obtain energy from food
19
Q
what is allometry?
A
it is the relation between the size of an organism and aspects of its physiology, morphology, and life history. it also means that it is the scale used when the aspect of biology do not vary proportionally to size
20
Q
what is Eexcretion?
A
Eexcretion is the energy released by the body through urine, feces, shedding, heat, etc.
21
Q
what is isometry?
A
it means that both dimensions remain proportional. the b value is close to one and when converting it to mass specific, it is zero
22
Q
what is negative allometry or hypoallometry?
A
it is when one dimension increases, the other dimension decreases to a lesser proportion. the slope (b) should be less than one
23
Q
what is positive allometry or hyperallometry?
A
it is when one dimension increases, the other dimension increases at a greater proportion . the slope(b) should be greater than one.
24
Q
where do organism exchange matter and generate energy?
A
across the membranes which is their surface area
25
what is retention time?
it is the time taken by the food to pass through digestive tract
26
why do organism need to obtain resources and excrete waste?
to support their mass which is their volume
27
why do organisms need energy?
organisms need energy to survive and reproduce
28
why do we use log transformations?
log transformation is sed for data normalization(making the data more regular) and it makes the power function linear
29
why is animal line higher? (greater intercept)
appendages (projection)
30
why is it an advantage for large organisms to have a small surface area to volume ratio?
because of easy heat retention. heat is produced by the entire volume and lost through surface area
31
whyis it a disadvantage for large organisms to have a small surface area to volume ratio?
because the nutrient exchange and energy generation will not be as sufficient
32
how does energy excretion work?
1. food gets broken down (chewing, enzymes, etc.). this takes a lot of energy and represents a net loss od energy. the harder the food to digest, the more energy required
2. nutrients are absorbed which leads to a gain of energy
3. when most energy is absorbed, the digestion rate decreases
4. all possible energy is extracted leaving undigestible "dregs" for excretion
33
what is the relationship between high quality food, energy and digestion?
high quality food (ex. meat) are easy to digest, less energy loss, greater rate, plateaus sooner, and higher plateau.
34
what is the relationship between low quality food, energy and digestion?
low quality food (ex. plant) are hard to digest, more energy loss, lesser rate, plateaus later, and lower plateau.
35
where is the optimal rate and optinal retention time of low quality food?
the optimal rate is at inflection point and optimal retention time is tangent of line drawn from origin
36
describe energy flow
energy is being recycled and not lost to environment
37
what is metabolic rate?
-metabolic rate is the rate of energy consumption.
-rate at which it converts chemical energy to heat and external work
-it is measured in calories or joules.
-it is the calories per unit time
38
what is resting metabolic rate (RMR)?
it is the energy expenditure at rest but riutine activities/day
39
what is basal metabolic rate (BMR)?
it is the metabolism at complete rest. lowest possible
40
what is standard metabolic rate (SMR)?
it is the metabolic rate measured at a specified temperature (ectotherms)
41
what is field metabolic rate (FMR)?
it is the metabolic rate measured in wild animals
42
which organisms does BMR applies to?
it applies to endotherms
43
which organisms does SMR applies to?
it applies to ectotherms
44
when does the BMR and the SMR of an organism applies?
it is the animal's metabolic rate while it is in its thermoneutral zone, fasting, and resting
45
when is the SMR specific?
it is specific for the prevailing body temperature
46
what is direct calorimetry?
direct calorimetry measures the rate at which heat leaves an animal's body
47
what is direct calorimetry?
direct calorimetry measures the rate at which heat leaves an animal's body. it is expensive and cumbersome (complicated, unmanageable)
48
what is indirect calorimetry?
it is the measure of oxygen consumed or carbon dioxide produced.it is cheaper and easier.
49
what are the two methods of indirect calorimetry?
respirometry and the material-balance method
50
what is respirometry?
it is the measuring of an animal's rate of respiratory gas exchange with its environment.
51
what is the meaterial-balance method?
it is the measuring of the chemical-energy content of the organic matter that enters and leaves an animal's body
52
what exponent do most organism fall on?
most organisms fall on exponent 0.75 and not 0.67
53
what is kleiber's law?
kleiber's law states that majority of animals' metabolic rate scales to the 3/4 or 0.75 of the animal's mass
54
why do endotherms have a higher metabolic rate than ectotherms?
because they have to thermoregulate
55
what is the relation between weight-specific resting metabolic rate and body weight?
weight specific metabolic rate decreases with increasing body weight
56
what is Eactivity?
Eactivity includes most forms of moverment above the resting state
57
how does the heat generated as activity increases helps the thermoregulation costs of a dormant or resting organism?
when activity increases, the heat generated may cover the thermoregulation costs of a dormant (resting) organism
58
what is Eproduction?
Eproduction represent both growth and reproduction.
59
what is the value of Eproduction the an organism has a balanced energy budget?
the value will be zero
60
what is the happens when an organism has more than enough energy consumed?
Eproduction will be positive and mass will increase
61
what is the happens when an organism has not enough energy consumed?
Eproduction will be negative and mass will decrease
62
what is homeostasis?
homeo= similar stasis= state
it is the regulation of an internal environment in the face os changed in the external environment. it is a very dynamic process that is tightly regulated by which the organism can change its bahaviour/metabolism to maintain its internal environment within an acceptable range
63
what are the parameters that organisms must control?
organisms must control pH, water (volume and pressure of cells and blood plasma, osmoregulation), solutes, temperature, oxygen/carbon dioxide, and heart rate
64
what is negative feedback mechanisms?
a change in a variable under homeostatic control triggers a response that opposes the change
65
what is a sensor?
it detects the environmental conditions
66
what is an integrator?
it analyzes signal from sensor, compares conditions to the set point and activates appropriate effector
67
what is an effector?
it causes a physiological change that opposes the deviation from the set point
68
what is posituve feedback mechanism?
a change in a variable under homeostatic control triggers a response that amplifies the change. pushes a system away frim hemeostasis-giid for achieving an outcome, once
69
what is thermoregulation?
regulating internal body temperature
70
what is ambient temperature (Ta)?
it is the temperature of the air surrounding a component
71
what is body temperature?
it is the temperature of an organism
72
what is heat generated by?
heat is generated by metabolism
73
how can heat be exchanged with the environment?
through conduction, convection, and radiation
74
how can body heat or temperature be regulated?
by changing the rate of heat gain and loss
75
what is conductance?
it is the rate of heat exchange
76
why do large organisms have lower conductance?
because they have a smaller SA/V ratio
77
what is homeotherm?
maintains "constant" body temperature (Tb) independent of ambient temperature (Ta). this can be a human (36C) or an earthworm (5C)
78
what is heterotherm?
Tb fluctuates with Ta. Ex. freshwater fish whose Tb changes with seasonal changes in the water temperature
79
what is an endotherm?
uses metabolism to generate body heat. (internal heat generation)
80
what is an ectotherm?
acquires body heat from environment (external heat source)
81
what is regional heterothermy?
organisms that are able to maintain different temperature zones in different regions of the body
82
where does thermoregulation occurs?
it occurs above and below the thermal neutral zone to regulate body temperature
83
what happens below the thermal neutral zone (hypothermy)?
shivering, vasoconstriction, piloerection, decreasing surface area, decreasing exposure (huddling/burrowing)
84
what happens above the thermal neutral zone (hyperthermy)?
panting, vasodilation, sweating, increasing surface area, decreasing exposure (to sun)
85
what is behavioural regulation of conductance?
moving to optimize heat exchange with the environment to attain an ideal body temperature
85
what are long term solutions for thermoregulation?
growing fur/adding fat, shedding, changing colour
86
what is exposure?
moving into or out of the sun/wind
87
what is grouping?
huddling together to share radiation
88
what is dormancy-daily torpor?
-it is a short (6-8 hours) reduction in activity
-about 10 degrees celsius drop in Tb and a lower MR
-reducing spending energy to stay warm (expecially when food is scarce in winter)
-high metabolic rate is turned down nightly/seasonally to reduce energy requirements in cold, drought and famish environments
89
what is dormancy-hibernation?
-Tb regulated close to Ta
-Massive reduction in metabolic rate
-lasts for about 2 weeks before arousal
-requires massive heat generation for arousal
-awake fir 1-2 days and then repeats
90
why do bears do not hibernate?
-only 10 degrees celsius lower Tb amd short duration (2-3 days)
-they have a small SA/V, lots of insulation (fat/fur) but food is scarce so they sleep and burn fat.
91
what is migration?
complete avoidance of poor environmental conditions
92
what is physiological regulation of conductance?
making physiological adjustments to optimize heat exchange with the environment to attain an ideal body temperature
93
what is membrane acclimation?
-membrane viscosity is affected by temperature
-different conformation decreases the enzyme's optimum temperature
-increased enzyme concentrations counter lower activity
-phospholipids change level of saturation
-accumulation of changes in every cell, acclimates the entire organism
94
what happens when an organism is acclimated to 5 degrees?
there are lots of unsaturated fatty acids and at 25 degrees, membranes are too fluid
95
what happens when an organism is acclimated to 25 degrees?
there are lots of saturated fatty acids and at 5 degrees, membranes are too viscous
96
what is vasocontriction?
-decreases conductane with environment
-endotherms:when cold to retain heat
-ectotherms:when hot to retain heat
97
what is vasodilation?
-increases conductance with environment
-endotherms:when hot to release heat
-ectotherms:when cold to increase heat gained from environment
98
what is internal insulation?
fat/blubber-internal insulation layer to slow rate of heat transfer
99
what is external insulation?
fur/feathers-external insulation layer to slow rate of heat transfer
100
what is piloerection?
the fluffing of fur/feathers decreasing the rate of heat transfer by increasing thickness of insulation layer
101
what is the advantage of having a thicker fur?
-animals changes the amount or thickness of fur between summer and winter
-thicker fur has better insulatory power and arctic animals change fur thicknedd seasonally
102
what does dark fur do?
-it absorbs ligt and generates heat outside of insulation layer (heat easily lost to environment)
-black fur traps radiant heat from the sun near the outside layer of fur, allowing it more easily to be removed by convection
103
what does white fur do?
-it allows light to reach skin and generates heat inside of insulation layer (keeps arctic animals warmer)
-allows sunlight to penetrate fur to warm the skin which is then protected from convective heat loss by the outer fur layer
104
what do hollow hairs do?
allows radiation to transmit down hair shaft, so that baby seals and polar bears gain the most solar heat.
105
what is sweating and panting?
heat loss due to evaporation
106
what are cryoprotectants?
molecules produced to lower freezing point and allow ice to form in extracellular spaces, but not internally
107
what are ice-nucleating agents?
antifreeze proteins prevents ice formation
108
what is shivering thermogenesis?
simulataneous action of antagonistic muscles generates heat without causing movement
109
what is non-shivering thermogenesis?
-special fat tissue (brown fat) that is loases with special mitochondria. instead of using PMF for ATP production, it's used to generate heat.
-used by organisms to raise Tb (especially newborns and organisms recovering from torpor, hibernation, nad winter sleep
-instead of using energy released on the transit across the membrane for ATP synthesis, it is sent through UCP1, which releases more of the energy as heat.
110
why are newborns more prone to hypothermia?
because there is a substantial amount of brown fat in newborns than adults and they have a higher surface to volume ratio
111
what are the other functions of brown fat?
it is also found in hibernating animal species which uses it to reheat themselves to operating temperature during arousal from hibernation
112
what is a muscle made of (bundled with)?
muscle fibres
113
why do hundreds of myoblasts fuse?
to form multi-nucleate cell during growth
114
what are muscle fibres filled with?
myofibrils
115
what do myofibrilsconsist of?
they consist of stacjs of alternating thick (myosin) and thin (actin) filaments
116
what are sarcomeres?
-functional unit of skeletal muscle
-arranged (bundle) of thick and thin filament
117
how are the thick and thin filaments arranged?
they are arranged along the length of the myofibril in sarcomeres
118
what is the sliding filament model?
muscles contract when the myosin filaments pull the opposing actin filaments toward each other
119
how do skeletons move?
muscles generate force
120
when do force generated by muscles increases?
when the number of cross-bridges betwen actin and myosin in sarcomere increase
121
how do the force generated by muscles increase?
by increasing the number of muscle cells in the tissue (more muscle cells/fibres=more sarcomeres) and increasing the length of the muscle tissue (longer muscle cells/fibres=more sarcomeres)
122
how does the force generated by any muscle decreases?
-it decreases with the speed of contraction
-rapid contraction decreases number of cross bridges
123
how does understanding the maximum metabolic rate help us?
it allow us to make predictions about reproduction, distribution, range, migration, and other constarints on survivorship
124
why are we capable of high output (10m/s) but can't sustain this over longer time periods?
because of physiological limitations on energy production
-limit rate of ATP production
-delivery of oxygen to muscles takes time
125
what happens to the metabolic pools of ATP?
they are instant energy and used up fast
126
what is phosphocreatine (PCr)?
it is the instant backup pool of ATP
127
what is oxygen debt?
use up pools of ATP/PCr and produces lactic acid.here are more oxygen getting used compared to what is produced/consumed.
128
what is recovery metabolism?
replenishes cellular pools of ATP/PCr and removes lactic acid
129
what is metabolic scope?
it indicates the scope (capacity) for activity
130
comparison between the metabolic scope between endotherms and ectotherms
endotherms have higher metabolic scope than ectotherms but they are similar when they have the same mass
131
how do you measure the mass-specific metabolic rate of an organism?
energy (volume of energy) required to move one unit mass of an organism (kJ/kg h)
132
how to measure the cost of transport (CoT) of an organism?
energy required to move one unit mass of an organism one unit distance (kJ/kg h x h/km = kJ/kg km)
133
how does inertial forces relate with mass?
inertial forces increases with mass
134
what is inertia?
tendency of a mass to resist a change in motion
135
what is momentum?
-tendency of a moving mass to sustain velocity
--will stay in motion unless something acts on it
136
what is drag?
the force generated in the opposite direction of an animal's movement by the density/viscosity of the medium (like friction)
137
how does drag forces relate with mass and velocity?
-drag foces increase with mass and velocity
-large organisms spend less enerrgy overcoming drag than small organisms
-as velocity increases, more energy has to go towards overcoming drag
138
what is thrust?
energy needed for forward motion
139
what are the forces acting on a runner?
-gravity (largest factor in activity budget)
-thrust (lots of energy from each step is transferred to ground)
-muscle action (constantly supporting our mass)
-drag (neglogible in air; force generated in opposition to thrust)
140
why is mass specific metabolic rate max higher in smaller organisms?
large organisms have longer muscles. smaller organisms have shorter muscles. it is more expensive to contract short muscles (less force generated)
141
relationship between limbs and velocity
as velocity increases, limbs move faster. muscles contract faster and more energt required
142
why do small runners have to work harder to move fast?
limbs and muscles are shorter so they bave more contact with ground
143
relationship between velocity and energy
as velocity increases, more energy can go towards generating forward motion. momentum increases and less contact with ground which means that there is less energy loss
144
description of the graph of velocity vs MRmax/sus and CoT
as velocity increases:
-mass specific metabolic rate increases linearly (small organisms have larger mass specific metabolic rate max than larger organisms)
-CoT decreases linearly (inertia/momentum, contact with ground decreases etc)
145
how to convert from mass specific metabolic rate to CoT?
x stays the stame but y is y divided by x
146
what are the forces acting on a swimmer?
-gravity (negligible factor in activity budget)
-thrust (energy needed for forward motion) (body plan (shape) adapted to minimize drag)
-drag (biggest cost to a swimmer) (density/viscosity of water is greater than air)
-buoyancy (generate neutral buoyancy (swim bladders))
147
what are the drags of a swimmer?
-viscous forces are skin friction drag and inertial forces are pressure drag
-in fishes, pressure frag is greater than skin friction drag
-in bacteria, skin friction drag is bigger than pressure drag
148
how to minimize drag in water?
shape. fast swimmers adopt drag-minimizing shapes
149
how do inertia affect swimmers?
swimmers must work hard to overcome inertia in a viscous environment. larger swimmers experience less skin friction drag
150
how does velocity affect the limbs?
as velocity increases, limbs move faster. muscles contract faster and more energy is required
151
why do small swimmers need to work harder to move faster?
they have shorter limbs/muscles
152
relationship between velocity and pressure drag
as velocity increases, pressure drag increases. energy expense rises sharply with velocity to fight pressure drag
153
why aren't Daphnia shaped like fish?
small swimmers live in a viscous world. inertial forces are negligible (never go fast enough to generate pressure drag)
154
what are the forces acting on a flier?
-gravity (more important at low velocities)
-thrust (energy needed for forward motion)
-drag (more important at high velocities)
-lift ( force generated that counters gravity that increases with velocity)
155
relationship between the mass of a flier and gravity
-fliers must work to overcome gravity
-larger fliers fight harder (greater mass)
-very small fliers (insects) affected much less
156
relationship between mass and drag
-fliers must work to overcome drag
-very small fliers "swim" through air due to higher relative density/viscosity
-larger fliers must work harder to overcome drag
157
relationship between velocity and mass/size of fliers
small fliers have to continually beat wings to stay aloft. this is the opposite to large fliers because they can glide to reduce energy expense
158
what is induced power?
energy requires to counter gravity
159
parasite power and induced power on fliers
parasite power requirement increases at high velocity. induced power requirement decreases at high velocity
160
what is parasite power?
energy requires to counter drag
161
why do runners have a high CoT and low for swimmers?
-gravity sucks
-negligible for swimmers
-fliers generate lift
-runners have to fight it with every step
162
what is the ideal for most organisms?
unlimited resources to support maximal growth, long life, continuous production of offspring (with high survival)
163
why do organisms do not live under ideal conditions?
their energy is spent to find food, avoid predators, etc.
164
what is the ultimate goal of managing an energy budget properly?
to have energy remaining to allocate for reproduction
165
what is an organism's fitness?
it is the reproductive success
166
what is the life history theory?
it means that every species has a pattern of growth and development, reproduction and death shaped by natural selection. success in the past shapes the life history traits of a species
167
how does the environment affects life history traits?
by influencing energy budgets (amount of light, food sources, shelter, wind, precipitation, etc)
168
what happens when 2 life history traits compete for a share of limited resources?
then it is impossible to maximize both traits simultaneously. any gains by one trait will result in a loss by the other
169
what is indeterminate growth?
growth of the organism continues throughout the lifespan (ex. ectotherms-reptiles, fish, plants, etc.)
170
what is determinate growth?
growth of the organism ceases when "adult" state is reached (ex. endotherms-birds, mammals)
171
what does asexual reproduction?
produces clones (exact copy)
ex. prokaryotes replicate their genome and then divide by binary fission
some eukaryotes replicate their genomes and divide by mitosis
172
what does sexual reproduction produces?
it produces recombinants (combined genomes). only in eukaryotes
173
how does sexual reproduction work?
replicated genomes are halved into gametes (sperm or eggs) and combined with other gametes to produce a zygote
174
the growth and reproduction in white suckers
indeterminate growth and growth slows at maturity (3-5 years)
175
what is passive care?
pre birth energy investment (seed development, gestation, etc)
176
what is active care?
post birth energy investment (raising an offspring, dispersing seeds)
177
what is the parental investment and offsprings of orchid seeds?
-little passive care
-no active care
-lots of seeds, some survive
178
what is the parental investment and offsprings of a mice?
-some passive care (few weeks )
-some active care
-multiple offspring, some live
179
what is the parental investment and offsprings of a coco-de-mer seed?
-lots of passive care
-no active care
-one large seed (high energy store to increase survival)
180
what is the parental investment and offsprings of an elephant?
-high passice care (18 months)
-high active care (4 years)
-few offspring
181
what is the trade off between parental care and survival of offspring?
as the number of eggs increases, less offspring survives because parents couldn't feed them all or care for them
182
what is the trade off between reproduction and survival of parent?
-in high fecundity, there is not enough energy for high fecundity and high survivorship.
-species with low fecundity and low survivorship go extinct
-no offspring means that there is enough energy to sustain self until offspring
-reproduction is costly in the young (they are not done developing) and old (can't maintain self)
183
what is semelparity?
individuals of the same species can breed only once in its lifetime
ex. pacific salmon: long trip from ocean to spawning stream- breed and die
184
what is iteroparity?
individuals of the same species can breed more than once in its lifetime
ex. atlantic salmon: short trip from ocean to spawning stream- return to ocean after breeding
185
what is fecundity?
ability to make many offspring
186
relationship between fecundity and body size
fecundity increases with body size. advantage to delaying sexual maturity until larger
187
what is the tradeboff between mating and lifespan?
-females that laid eggs had shorter lifespans
-males housed with virgin females reproduce and have shorter lifespans
-also larger males live longer
188
what are the life history strategies of r-selected?
-small offspring/adult size
-early sexual maturity
-semelparous
-high fecundity (lots of offspring)
-low parental investment
-low juvenile survivorship
-short lifespan
-evolved to reproduce quickly
189
what are the life history strategies of k-selected?
-large offspring/ adult size
-late sexual maturity
-iteroparous
-low fecundity (few offspring)
-high parental investment
-high juvenile survivorship
-long lifespan
-evolved to compete
190
how do we know if an organism is an r or k or life history tables?
summarize information on age structure, size, life-history (reproductive stage), ans survivorship of a population. it is also used for predicting how a population will change over time
191
how to manage life history tables or population?
-crops and livestock (farming planning)
-conservation efforts (captive breeding prgrams)
-pest/weed control
-etc
192
what is a type one survivorship?
-low mortality until end of life
-large animals, few young
-high parental care, high juvenile survivorship
-k-selected
193
what is a type two survivorship?
-constant rate of mortality throughout the lifespan
-mix of r and k traits
194
what is a type three survivorship?
-low juvenile survivorship
-mortality rate decreases with age
-r-selected
195
what is population?
all of the individuals of a given species that live and reproduce in a particular place
196
what is population size?
it is the number of individuals alive at a particular time in a particular place and is influenced by births, deaths, immigration, and emigration
197
what is the exponential model of population growth?
-it is a model under ideal conditions
-the per capita growth rate (r) will be at a maximum for that population: rmax=intrisic rate of increase
-in this model, rmax is always constant and positive
-rmax varies by species. (ex. bacteria is about 10; humans are about 0.0001)
-if bacterias have everything they need, they will grow really fast
198
what does it mean when an organism has a lower rmax?
they need to convert a lot of energy into body material to reproduce
199
what limits population growth?
-tempertaure
-precipitation (in plants)
-predators
-disease
-food availability
200
what is carrying capacity?
an environment can only support a certain population size
201
relationship between per capita growth rate, population size, and carrying capacity
as population size approaches carrying capacity, per capita growth rate decreases. as population increases more than the carrying capacity, per capita growth rate becomes negative
202
what are the biotic density-dependent factors?
-food availability
-shelter
-mates
-predation
-disease
-it has an increasing affect as N becomes large
203
what are the abiotic density-dependent factors?
-temperature
-precipitation
-light
-disturbance (fire, flood, etc.)
-it has an effect at any population size
204
relationship between r selected species and population growth
-stays in environments with disturbance
-small in size
-early in maturing
-stay in bottom of curve
205
relationship between k selected species and population growth
-in the graph, they are close to carrying capacity
-strong competitors
-bigger in size
survive in extremes
-stays in environment with less disturbance
206
how does r selected species influence population growth?
-low survivorship
-higher growth rate
-low parental care
-semelparous
-short lifespan
-annual plant, weeds
-high fecundity
207
how does k selected species influence population growth?
-lower fecundity
-approach k (carrying capacity)
-large in size
-long lifespans
-iteroparous
208
how does rt compare to r in covid19?
-both values measure the rate of increase of the population size
-exponential/logistic depend on the individuals in the population
-epidemiology is much more complicated
209
what is ecosystem?
are communities of organisms interacting with their physical environment under the influence of environmental factors
210
what is ecosystem energetics?
is the study of how energy is fixed by autotrophs and made availble to heterotrophs
211
what is energy measures as?
biomass (the dry weight of organic matter in an organism or ecosystem)
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what are primary producers?
autotrophic organisms that fix inorganic nutrients (C, N, P, O, etc.) into organic molecules. they carry out primary production (pp)
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what is primary productivity?
the rate at which energy is fixed (expressed as the amount of C fixed per unit area per unit time (ex. tonnes C/(km2year)
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what is gross primary production?
total amount of energy fixed into organic molecules in an ecosystem
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what is net primary production?
-what the producer makes, minus what the producer uses for itself
-the amount of energy for growth
-measured as biomass
-gross primary production and net primary production tells us how much energy is available to other trophic levels
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factors affecting primary productivity
-light (photosynthesis needs light) (UV, radiation)
-Temperature (enzyme reaction increases with temperature)
-precipitation (water hogging, low sunlight)
-nitrogen (soluble is washe away and tends to imit pp in terrestrial)
-phosphorous (insoluble are more limiting in aquatic)
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what are primary consumers (herbivores; second trophic level)?
-organisms that consume organic molecules (biomass) of primary producers
-use the energy consumed (Ein) to support its energy budget
-excess will turned into new biomass (Egrowth)
-biomass production is called secondary production
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what are secondary/tertiary consumers (carnivores/omnivores; third/fourth trophic levels)?
organisms that consume the organic molecules (biomass) of consumers in a lower trophic level
-use the energy consumed (Ein) to support its energy budget
-excess will beturned into new biomass (Egrowth)
-biomass production is called secondary production
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what are omnivores?
eat both producers and consumers
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what are decomposers/detritivores?
-organisms that consume the dead organic matter of producers, primary consumers, etc.
-secondary production
-cycling nutrients
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what is bottom-up control (eutrophic cascade)?
-resource abundance regulates trophic structure
-the energy in each trophic level is determined by the energy in the lower trophic level
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what is top-down control?
-predation regulates trophic structure
-organisms in each trophic level are limited by predators in the next trophic level
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what is trophic cascade?
adding/removing a top predator from an ecosystem often results in an alternating (cascading) effect down the rest of the food web/chain
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what are nutrients?
elements required by an organism
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why is Earth a closed system?
because energy flows and nutrients cycle
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what are biogeochemical cycles?
pathways that describe how nutrients move between biotic and abiotic components of an ecosystem
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what are the three major geological nutrient reservoirs?
terrestrial, aquatic, and atmospheric
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what are the three potential phases of nutrients?
gases (h2o, co2), soluble (C,N,O), and insoluble (P, K Fe)
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what is the most abundant element in organisms?
carbon. about 50% of dry mass
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what is the unit energy currency in organisms and ecosystems?
carbon
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why are the carbon levels high in winter?
because of burning of fossil fuels
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why are carbon levels low in summer?
because plants are taking up co2
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what is the reason for increase in co2 levels?
-co2 levels in the past (measured from air bubble trapped inice) indicate that the increase is recent
-co2 has increased 30% iin the past 50 years
-recent increase is due to human activity
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why are most co2 from fossil fuels?
-most organisms contain 12C and also fossil fuels.
-when fossil fuels are burned, they release 12C. this dilutes the atmospheric 13C:12C ratio, which we can measure
-therefore, extra co2 is coming from fossil fuels
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what is the greenhouse effect?
the Earth eventually radiates the energy absorbed from the sun back into space
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what happens to the carbon?
-antropogenic (carbon coming from human activity) co2 generation has increased
-half of anthropogenic co2 stays in the atmosphere
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relationship of human populations and greenhouse gases
the increase in greenhouse gases is directly related to the exponential increase in human populations and industrialization
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where does carbon go after being burned?
ocean sink, land sink, atmosphere
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what happens to the anthropogenic co2 that is absorbed by the oceans?
-co2 reacts with h20 and forms carbonic acid, h2co3,which lowers pH
-carbonic acid dissociates releasing bicarbonate, hco3- + H+
-the H+ reacts with carbonate, co3 2-, forming more bicarbonate
-shell forming marine organisms (corals, molluscs, crustaceans, echinoderms) require carbonate to form their calcium carbonate shells/skeletons
-this slows the rate at which shell-forming occurs, leaving them vulnerable to predation and infection.
-it is predicted that acidification will start dissolving calcium carbonate shells by 2050
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