Chapter 3 - Physical conditions and the avaliability of resources (CHAPTER + SLIDES) Flashcards
slides notes are included!!
Conditions
Physiochemical features of the enviornment
- temperature, humidity, pH, salinity
- an organism can alter conditions in its immediate enviornment
- are not consumed or used up
Resources
Consumed by organisms in their course of their growth and reproductions
- organisms may competed with eachother for resources
Extreme conditions
only appear ‘harsh’, ‘benign’ or ‘extreme’ to us as humans, but are completely normal for the organism.
Effects of conditions
Creates response curves!!!
y axis = performance of the species
x axis = intensity of the condition
1) Temperature, pH, salinity, moisture
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2) Usually poisons such as concentration of arsenic
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3) Toxic at high levels but required for low levels
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Have three lines on the graph, upmost represents reproduction, the middle represends individual growth, and the last is for individual survival
Final size of an organism
Rates of growth + development determine its final size
Temperature for example will affect the final size as it impacts the performance of the species at varying intensities. (This can be used to predict what effect global warming may have on us)
Thermophiles
Love the heat. 60°C ≤
Chilling injury
Extended periods of inactivity due to the cold
- leads to cell membrane breakdown
- the timing and duration of the temperature exposure is important.
Rates of physical processes
Can be modulated by conditions
Photoperiod
Length of the period of daylight within the daily cycle
- example: birch treese
Diapause
Getting ready for winter / slowing down the development of the body. (Typically an insect)
Acclimitization/Acclimation
Altered response to more extreme conditions.
- example: faster metabolism, antifreeze, etc.
Acclimation is the same thing but scientific not natural
Motile animals
Move
Decidiuous
Annual shedding
Sedentary animals
dont move, they stay
Conditions effects on organism
An organism will sufer if its food is another species that cannot tolerate an enviornmental condition.
- example: rush moths need a flower.
A condition can increase/impact the development of disease
- example: fungal spread / parasitic growth / high or low temperatures.
A condition can also increase or decrease competition.
Physical conditions follow a seasonal cycle
Organisims can therefore change and anticipate whats gonna come by acclimating.
Endotherms
Body temperature regulated by an internal mechanism
- good for a bigger temperature range
- is independent to enviornmental conditions, but has a high food requirement
Ectotherms
Body temperature is determined by the enviornment
Intermediate forms
Endo/Ectothermics dont have absolute distinction. Some intermediate forms are present
- tunas and sharks
- hamsters hibernate despite being endothermic so they lower their temp.
You wont find small aquatic endotherms
You wont find large terrestrial ectotherms
(komodo dragon biggest)
Poikilotherms
Have variable body temperature
Homeotherms
Maintain constant body temperature
Endothermic adaptations
For the cold
- small limbs (low surface area to volume
- dense fur
- feathers or fat
For the hot
- long limbs (to dissipate heat better)
- thin fur
- long ears
Seasonal temperature effects
Temperatures that very seasonally can create annual changes or dedications such as hibernation
Acidophilic
Loves acidic enviornments
Eco-engineering
Engineering by use of living organisms.
Resources for photosynthetic organisms
Fixed and rooted organisms cannot search for food
- they must rely on growing towards resources or just catching passivley.
Have 4 resources
- solar radiation
- Water
- nutrients
- carbon dioxide
RESOURCE: Solar radiation (“light”)
High intensities can lead to photoinhibition or overheating
- can vary for plant
The light is always changing depending on angles and intensity
(Shade and sun leaves can grow on the same tree)
Shade leaves
Fewer, larger, neat angles
Sun leaves
Smaller, crowded, various angles
RESOURCE: Water
- It impacts rates of photosynthesis
- Is lost during photosynthesis
- If the rate of the uptake is less than the rate of release, then the plant will dry out and WILT.
WATER: Avoiders
- Desert annuals or annual weeds and crops
- short lifespan / only photosynthesize when water is avaliable
- usually dorment
- perrenials shed when there is low water.
WATER: Tolerators
- long lived leaves that transpire slowly
- tolerate drought & low water avaliability but have a small photoynthetic rate
WATER: Alternatives
- Decidiuous trees shed leaves every 2-4 months (in australisa)
- Tranpisration can cool down leaves
Dessication tolerance
Survive at low body of water content for long periods of time.
WATER: C3 pathway
Wasting lots of water, but high photosynthesis rates
WATER: C4 pathway
Is water efficient, because there is no need to open stomata much.
- It is a newer pathway
- Hot and dry plants use it
- can be in low carbon dioxide habitatis
- but is inneficiatent at low radiation
WATER: CAM (Crassulacean acid metabolism)
MOST efficient at water retention
- carbon dioxide is absorbed as night and fixed as an acid till the morning where it can be used
Interstitial Water
Water stored between soil particles
WATER: Sandy soils (wide pores)
Not much water but easy to widthdraw from
WATER: Clay soils (fine pores)
More water but hard to widthdraw from because of surface tension
Water as a resource depletion zone (RDZ)
- The more water is sucked up by the plants the more stronger the tolerance of that plant will need to get to water depletion. This kills more rapidly respiring plants.
- the root shapes of systems are therefore important
=> In waterlogged areas plants tend to use superficial root system but if a drought happens then this type of system will kill them
=> Plants can also use a deep tap root system, but it is of no use if theres not enough water.
RESOURCE: Nutrients
- Essential: N, P, S, K, Ca, Mg, Fe
- Trace nutrients: Mn, Zn, Cu
- obtained from soil or water
NUTRIENTS: Nitrogen uptake
more widely spaced roots
NUTRIENTS: Phosphorous uptake
more branched roots
NUTRIENTS: Soils
Soils are patchy and heterogenous
- some nutrients are too tightly bound to the soil. So root architecture detemines the plants foraging efficiency.
- Algal plants also need architecture
(low nutriencs will create smaller algae cells)
Heterogenous
Diverse in character or content.
RESOURCE: Carbon dioxide
Concentrations in atmosphere tend to vary but right now are exponentially high
- They cary during the year (seasonal uptake by the northern hemisphere in the summer)
CARBON DIOXIDE: Generalities noticed by exponentially high levels
- The increase in crop yield is less than predicted
- forest plots have a greater responcce thatn field crops.
- the generalities can change depending on the ecosystem
Autotrophs
- use photosynthetic radiation, water, and carbon dioxide
- assemples them into complex molecules that heterotrophs use
- are primary producers
Green algae, plants and cyanobacteria
Heterotrophs
Metabolize autotrophs
Chemoautotrophs
Use chemical energy.
Decomposers
eat already dead food
Parasites
Feed on alive pray and usually don’t kill their host
Predators
Kill and eat many organisms
Grazers
Consume parts of an organism (but usually dont kill it)
Polyphagous Generalists
Feed on a wide variety of goods
- common in herbivores
- tend to have a long life span
Monophagous Specialized diets
Feed on only a single species or species closely related to that one.
- common in parasites
- caterpillars
- short life span
- have a specialized mouth
Bark as a food source
Is usually for specialized diets
Plants tend to have a high C:N ratio
The shoots and the roots are full of protein
- THere is diveristy in specialized mouthparts and digestive tracks just to eat bark
Plant as food
Plant is difficult to digest so must chew
- herbivores enter mutualistic relationships also with their bacteria and protozoa in their guts that can digest parts they cant.
- sometimes herbivores have an organ called a rumen which is a place for the bacteria to be in where they digest
Other facts you might need to know
Herbivores burn off lots of carbon
Carnivores gather energy from proteins and fat
Algae are full of protein but make more nitrogenous waste
Carnivores as a food source
- Not difficult to digest but are difficult to catch
Defenses for their resources
Organisms tend to have chemical, physical, morphological and also behavioral defenses
- they do this to protect some resoueces
- for example plants have secondary chemicals that serve only to protect the resources.
Noxious Plant Chemicals
Constituitive & Inducible chemicles
Constituitive chemicals (quantitiative)
Stored in the most important part of the plant
- are effective at high dosages
- are always produced and there in the plant
Inducible chemicals (qualitative)
Stored in the less important parts of the plant
- are effective at low dosages
- produced only if the plant is damaged
Specialization in eating noxious plant chemicals
- Acid secretion in cowries
- monarch caterpillars with milkweed
Crypsis
Morphological traits and color of the organism will reduce the likelihood of it being used as a resourse
Noxious
very bright, so that the hunters remember not to eat
Mimics
tend to mimic noxious species
Protection with behavioral traits in animals
- live in holes
- “playing dead”
- preparing a retreat
- migrating through the oceans vertical column (up at night to feed)
- show threatening displays
Intraspecific competition
Competition within the same species for resources
- 2 types
Exploitation competition
Intraspecific competition that can deplete resources that are avaliable to other individuals
Interference competition
Fight for food / marking territory
Vital rates
- survival, growth then reproduction
Competition
leads to decreased growth
- plays a role in natural selection
- favors the ‘winner’
Density dependence
Effects of intraspecific competition are densiy dependent
- there are greater effects if more indivudals are present because it leads to a Resource Depletion Zone (RDZ
Weird concept about density dependence you should know
If there is originally no evidence that at these densities individuals are affected by other individuals it shows no intraspecific competition. But if all of a sudden there is increased density then there is less birth so now the situation is density dependent and so there is intraspecific competition.
Habitat
Where an organism lives
Niche
the limits, for all important enviornmental features, within which the individuals of a species, can survive, grow and reproduce.
n-dimpensional hypervolume
ecological niche of a species as a map
n
number of dimensions that make up the niche
- usually are conditions
2 -dimensional hypervolume example
Temperature and salinity. 3 overlapping circles
Inner circle = 0% mortality, can reproduce
Middle circle =25% mortality, can grow
Outer circle = 50% mortality, can survive
outside of circle = 100% mortality
Undercompensation
At high densities, the fecundity per individual still increases.
- final increase
Overcompensation
At high densities, the fecundity per individual decreases.
- final decrease
Exactly compensating density dependence
final density is irrespective of the inidital density.
