Lecture 2: Biogeography ⢠Biogeography: abundance and diversity of ...
Lecture 2: Biogeography • Biogeography: abundance and diversity of organisms depends on available resources • Resources such as: o Energy o Light o Temperature o Nutrients: § Water (H2O) sugars and fatty acids § Air (CO2, O2) sugars and fatty acids § N, P (sugar phosphate backbone, proteins in DNA) K, Na (electrolytes) § S (proteins) § Mg (chlorophyll) § Ca (electrolyte and skeletal) o Micronutrients (Cl, Fe, B, Mn, I, Cu, Zn, Ni)-‐ roles in enzymatic, catalytic roles • Limitations in terrestrial ecosystems: o Energy-‐ light limited areas include: § Deep in ocean, caves (formed by water-‐ macro and micro nutrients brought), volcanic vents (H2S) o Temperature extremes include: § Limitations to where life can be sustained: § Highest approximate temperature: 120˚C (archaea and bacteria can sill live) § Lowest approximate temperature: -‐45˚C o Driest places on earth: § Antarctica § Arctic § Atacama desert, Chile: so dry, so little water, weather stations never recorded waterfall • No bacteria living • Soil, sand so sterile because so dry, therefore no organism can live § Lake Eyre, South Australia: does fill with water • Pelicans, fish lizards. Geckos come into lake o Wettest places on earth: § Cherrapunji, India: high number/ abundance of species • Monsoon rains therefore very wet § Babinda creeks QLD: biodiversity • Famous for birds-‐ paradise bird Distribution of water: • Consistency, availability of water-‐ abiotic factor • Distribution and abundance of organisms in terrestrial environments depends on the availability of WATER • Movement of air determines the distribution of water (rain, snow, fog) on land • Movement of air follows simple physics: 1. Hot air carries more water than cold air
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v Water breathed out from 37˚C to much lower temperature precipitates 2. Hot air moves up and cold air moves down: v Cold air is more dense (molecules close together) than hot air v Energy radiating from surface heats air 3. Hopkins’ bioclimatic law: air cools down as it goes higher v 180m higher= 100km closer to pole 4. Coriolis effect: longitudinal movement on a rotating object results in apparent latitudinal drift: v Depends on earth’s spin (deflection of air due to earth’s spin) Warmer closer to the equator, because sunshine (heat energy) acts directly rather than obliquely
Convection current: Blue: water carrying current, white: dry air
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Convection of air is determined by the incidence of sunlight o At the equator and at 60˚ latitude ascending air releases water, resulting in an abundance of vegetation o At the poles and at 30˚ latitude, descending air sucks water away, resulting in deserts o Equator hotter (air rising-‐ hot) than poles (air descending-‐ cold)
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v Water breathed out from 37˚C to much lower temperature precipitates 2. Hot air moves up and cold air moves down: v Cold air is more dense (molecules close together) than hot air v Energy radiating from surface heats air 3. Hopkins’ bioclimatic law: air cools down as it goes higher v 180m higher= 100km closer to pole 4. Coriolis effect: longitudinal movement on a rotating object results in apparent latitudinal drift: v Depends on earth’s spin (deflection of air due to earth’s spin) Warmer closer to the equator, because sunshine (heat energy) acts directly rather than obliquely
Convection current: Blue: water carrying current, white: dry air
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Convection of air is determined by the incidence of sunlight o At the equator and at 60˚ latitude ascending air releases water, resulting in an abundance of vegetation o At the poles and at 30˚ latitude, descending air sucks water away, resulting in deserts o Equator hotter (air rising-‐ hot) than poles (air descending-‐ cold)
