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ESC 556 week 3. Conditions and Resources: Major Determinants of Ecology. Definition: An abiotic environmental variable, which fluctuates in space and time, and to which organisms vary in their response Temperature, moisture, pH, salinity Not the source of competition - PowerPoint PPT Presentation
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ESC 556 week 3
Definition: An abiotic environmental variable, which fluctuates in space and time, and to which organisms vary in their response
Temperature, moisture, pH, salinity Not the source of competition Niche concept (Hutchinson 1957)
Multidimensional (conditions and resources) space that can support a viable population
Spatial, functional, behavioural An organism’s adaptations, resources,
lifestyle Examples
Primary production Bioturbation
Fundamental vs. realized niches Overlap of niches
Temperature Moisture pH Salinity Soil structure Pollutants
Variation Latitudinal Seasonal Altitudinal
Continentality Microclimatic variation Depth variation
Terrestrial organisms Sea - Land Movement problem Relative humidity Temperature Plants
Roots Condition + resource
Adaptations Either live in humid environments
Soil and water 3 – 9 Indirect effects
Nutrient availability Toxin concentrations
Aquatic animals Osmoregulation Toxic ion concentration Food resources
Isotonic Hypotonic
Pumps Halophytes
Tolarate high salinity Vacuoles
Euryhalines Tolorate salinity fluctuations Osmoconformers Osmoregulators
Stenohaline Not tolerant of fluctuations
Volcanic activity Industrial activity OH + SO2 + O2 H2SO4 OH + NO2 + O2 HNO3 pH = 3 In many freshwater systems pH = 6 – 8
Direct mortality Reproduction Leaching – 1200 lakes in Canada devoid of life
Trees Canopy damage & Forest decline
Air Ventilation of an organism Aeration of a microhabitat Desiccating agent
Water Not desiccating Wave action Currents Movement of materials
Physical and chemical nature Rocky vs. particulate substrate Attachment strategies
Particulate – Anoxic Terrestrial soil
Affect plants + affected by plants
Strong attachment Holdfasts, byssus threads (mussels),
suction cups (limpets, chitons, fish) Physically resistant body structure Behavioral adaptations
Cracks + gregariousness
Lotic environments Micro-organisms
Wet rocks & epilithic film Flattened body profile Behavioural
Rheotactic Phototactic
Contaminants vs. Pollutants Pollution ecology Essential vs. Non-essential substances
Materials Space Competition Solar radiation Nutrients Organisms as food Essential vs. Substitutable Complementary vs. Antagonistic
The total yield or biomass of any organism will be determined by the nutrient present in the lowest (minimum) concentration in relation to the requirements of that organism
If not used, lost Change w/ latitude Resource continuum – different
wavelengths 400-700 nm - PAR
Euphotic zone
Seasonal vs. random variations Sun species vs. shade species Water
Restrict photosynthesis vs. suffer desiccation
C3 – phosphoglycerate – 3 carbon molecule
C4 – 4 carbon molecule CAM – crassulacean acid metabolism) –
4 C
Photosynthesis Water CO2
O2
Consumed Metabolism Plants – root systems Animals – drink
Kangaroo rats – metabolic water Influence distribution and abundance
Animals & Plants Limiting factor in aquatic systems Solubility
Terrestrial organisms
Vital for photosynthesis 0.033 % of air Terrestrial autotrophs & Aquatic
photsynthetic organisms Not a limiting factor
Animals – food Plants – soil/water
Lack of water lack of minerals Macronutrients
N, P, S (primary nutrients) K, Ca, Mg, Fe (secondary nutrients)
Trace elements Specialists
All heterotrophs Decomposers Parasites Predators
Grazers Generalists vs. specialists Seasonal Digestibility
Gizzard Ruminant mammals
Bird beaks Finches & European Shore birds
Physical defenses Chemical defense
Cyanides, acids, toxic substances Morphological defenses
Crypsis Aposematism Batesian mimicry
Behavioural defenses Nocturnality Living in holes or burrows Distraction Threatening methods
Plants Animals – territories Other resources Physical packing Breeding / hibernation Nesting