chapter3 Flashcards
Endotherm
An organism that generates heat internally to regulate body temperature
Acclimation
Habituation of an organism’s physiological response to environmental conditions, usually in laboratory settings
Thermophiles
Organisms adapted to live in high-temperature environments
Wilting
The loss of rigidity in non-woody plant parts, often due to water loss
Acidophiles
Organisms that thrive in highly acidic environments
Mimicry
The resemblance of one organism to another or to an object for a selective advantage
Grazer
An organism that consumes parts of many prey organisms without killing them immediately
Ectotherm
An organism whose body temperature depends on external heat sources
Photoinhibition
The reduction of photosynthesis with increasing light intensity
Tolerance
The limits within which a species can survive, grow, and reproduce
Resource
Something consumed by an organism, such as food or water, making it unavailable to others
Deciduous
Trees that bear leaves rather than needles
Chilling injury
Damage from exposure to temperatures slightly above freezing, causing cell membrane breakdown
Acclimatization
Habituation of an organism’s physiological response to natural environmental conditions
Diapause
A state of arrested development, with decreased metabolism, common in insects, often seasonal
Parasite
n organism that feeds on a host without immediately killing it
Autotroph
An organism that produces its own organic material from inorganic sources
Habitat
The place where an organism lives
Glycerol
An anti-freeze compound in springtails.
Phenology
The study of the timing of seasonal biological events
Aposematism
Conspicuous appearance of a noxious or distasteful organism to deter predators.
conditions
are physical or chemical properties of the environment
are altered by the presence of organisms
are not consumed or used up by organisms
e.g
temperature
relative humidity
pH
salinity
stream flow rate
pollutant concentration
Resources
Are consumed by living organisms
Are a subject of competition between organisms
e.g
Radiation (plants)
Water
Food
Substrate
Nesting sites
Extreme” conditions? dos donts
Do´s
ºC
Atm/Bar/Psi
Ph
% air humidity
Dont´s
Hot/cold
High/low pressure
Acid/alcalic
Humid/arid
Conditions are altered by living organisms examples
Swimming waterfowl maintain holes in the ice cover
Tropical rainforests have an influence on air humidity
Mangrove forests absorbe wave energy
Thus they reduce the impact of tsunami´s
eco engeneering
engineering by use of living organisms
Effect of conditions
optimum curve: goes from individual survival s to individual growth g to reproduction r which is the optimum and back to individual growth to individual survival
lethal at high intensities: starts too high goes down rapidly to r then g then s then 0
resources at low intensities, lethal at high intensities: starts super low goes up almost straight but to a destroying point then falls rapidly from r to g to s
Acclimatization
Acclimatization is the process of phenotypical adjusting to changing conditions
e.g.
Training at high altitudes causes an increase in blood volume and amount of red blood cells
Poikilotherms
Have variable body temperature
Homeotherms
Maintain constant body temperature
Ectotherms
Body temperature is determined by environment
Endotherms
Posses internal heat regulating mechanism
Endo/ectotherms: intermediate forms
Tuna and some sharks can have a core temperature that is < 10ºC higher than the surrounding water
Changes in body temperature of the European hamster during a 3-day bout of hibernation
The costs and benefits of endothermy
Relatively independent of environmental temperature
Can stay at peak performance in a broad temperature range
BUT:
High food requirement
Subject to overcooling
Have to cope with seasonal temperature fluctuations
biggest terrestrial ectotherms
komodo dragon, back in the day it was dinosaurs, tianoboa(extinct) mostly crocodiles and reptiles
smallest aquatic endotherms
marine otter (Lontra felina); 3-6 kg, vaquita
Selection pressures on plant leaves
Light catchment
CO2 uptake
Water conservation
Water release
Resistance to herbivores
Physical strenght
Plant resources: radiation
c3: shade mosses,planktonic algae around0 co2 uptake at 4 radiation, shade herbs around 0 CO2 and 3,5 radiation, beech like 15 co2 mg around 5 radiation, sun herbs around 25co2 mg at 8 radiation, wheat around 30 co2 around 8 radiation
c4 corn 50co2 9 radiation, sorghum 55 co2 at 3 radiation
shade and sun leaves
Shade leaves are fewer, larger and at neat angles to the incident light
Sun leaves are smaller, crowded and at various angles
Plant resources: water
Water enters trough the roots and exits through the stomata
When uptake < release, the plant wilts and eventually dies
Coping with water deficiency
- Deep root systems can pump soil water from deeper layers.
E.g. the sagebrush (Artemisia sp.) - rapid stomatal closure during the onset of drought
- Smaller leaf size
- Water storage in plant organs
- leaf abscission
E.g. Cryptantha flava, a desert plant, sheds its leaves after a prolonged dry period - Dessiccation tolerance: the plant can survive periods of low body water content
E.g. the common seaweed Fucus spiralis can survive 95% dehydration - Plants that use CAM and C4 photosynthetic pathways have a higher affinity for CO2
They absorb more CO2 per unit of water lost
Inefficient at low radiation intensities
Plant resources: mineral nutrients
Plants extract key minerals from the soil
Soils are patchy and heterogenuous
Roots tend to branch profusely in the richer patches
Interstitial water: Water that is stored between the soil particles
“Resource Depletion Zone” (RDZ) around roots
Some minerals (e.g. NO3-) are loosely bound to the soil particles and rapidly diffuse through the interstitial water
A widely spaced root system will maximise nitrate uptake
Other minerals (e.g. PO43-) are tightly bound to the soil particles and hardly diffuse through the interstitial water
A highly branched root system will maximise phosphate uptake
Plant resources: CO2
Diffusion and mixing of CO2 are very rapid
Resource Depletion Zones of CO2 are unlikely
No competition between plants for CO2
polyphagous
Generalist feeders (polyphagous)
Often long lifespan
monophagous
Specialist feeders (monophagous)
Often short lifespan
Specialised mouth parts
Decomposers
feed on dead material
Parasites
Feed on one or very few hosts while they are alive but do not usually kill their host
Predators
eat many prey organisms, typically killing them
Grazers
Consume parts of many prey organisms but do not usually kill their prey
Intraspecific competition:Exploitation competition
Competition in which any adverse effects on an organism are brought about by reductions in resource levels caused by other, competing organisms
Intraspecific competition:Interference competition
Competition between two organisms, in which one physically excludes the other from a portion of habitat and hence from the resources that could be exploited there.
Intraspecific competition
Competition lowers the average survival and fecundity of individuals
Competition is density-dependent.
At low densities, there is no competition
undercompensation
At high densities, the fecundity per individual declines
The fecundity of the total population may still increase: undercompensation
e.g
the total number of seeds produced by Vulpia fasciculata continues to rise as densities increase
Overcompensation:
increases in initial density lead to reductions in final density , Overcompensation is a well-known mechanism to farmers. Vegetables should not be planted to close to each other, less the total crop yield will decrease
Exactly compensating density dependence
The final density is the same irrespective of initial density.
The ecological niche
Niche: The limits, for all important environmental features, within which individuals of a species can survive, grow and reproduce
e.g
A simplified model of an ecological niche, consisting of two variables: salinity and temperature
Realistic niches contain a much larger number of dimensions
