BIOL1003 Lecture Notes - Lecture 2: Ecological Niche, Biogeography, Microclimate
BIOL1003: Module 4 – Ecology
Lecture 2 – Niches, Biomes, Biogeography and Climate
• Niche: fundamental niche versus realised niche
o What roles do organisms fulfil in their habitats (where?)
• Fundamental niche
o Possible distribution of the organism as determined by its evolutionary history
o Much bigger then where they are actually found - mice example
o If there weren't interactions preventing us doing so
o Barnacles - all can live above or below water, but one will live above, one will live below
• Realised niche
o The actual distribution of the organism is limited by interactions with other organisms
• Population dynamics
o Shows how organisms are utilising their niches: are they thriving or dwindling?
o food security
o disease
• Biomes: major life zones
o Terrestrial biomes are most often characterised by the main vegetation
o Aquatic biomes by their physical environment
o They are not defined lines - they sort of melt or merge into the next ones
o While put in to district categories, they can look very different in different places
• Temperate vs alpine heathland
• Biogeography
o Abundance and diversity of organisms
o Availability or resources
• Water
• Shelter
• Energy: light, temperature
• Nutrients
▪ Water - sugars and fatty acids
▪ Air CO₂ ad H₂O - sugars and fatty acids
▪ N, P - DNA, proteins
▪ K, Na - electrolytes
▪ S - proteins
▪ Mg - chlorophyll
▪ Ca - electrolytes and skeletal
▪ Micronutrients (Cl, Fe, B, Mn, I, Cu, Zn, Ni)
o Limitations in terrestrial ecosystems
• Energy: limited light
• Temperature: High = 120°C, low =-45°C
• Climate
o Temperature, sunlight, wind and precipitation
o Macroclimate - patterns on the global, regional and landscape level
o Microclimate - finer scale patterns, e.g. community of organisms on a tree trunk
o Distribution of water
• Distribution and abundance if organisms in terrestrial landscapes/environments
depends primarily on the availability of water
• The temperature can be quite similar, but rainfall significantly different = very
different biota
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