What is a biome? And how are they characterized by?
Is a biome only found in one geopraphical location?
A group of ecosystems sharing similar climatic characteristic
By their producers.
No, it can be found in multiple places on earth. (not continuous)
What are the 3 main abiotic factors that determine a biome structure? What do they determine?
Insolation: amount of solar energy per year
Temperature
Rainfall: net precipitation
Determine which kind of plants can grow -> NPP, kinds of consumers…
What controls insolation?
Latitude: distance (N or S) from the equator -> determine the angle of incidence of sunlight.
-> Direct incidence at equator (90° angle of incidence) = most insolation
Tilt of the earth can cause seasonal variations.
What controls the temperature?
Latitude: polar regions receive less solar energy.
Ocean currents: moving currents of warm water bring warm air masses with them.
ex: England vs top of Quebec
What controls the rainfall?
At the equator warm aire rises and moves away from the equator -> as it moves away from the equator, it cools and cold air holds more moisture, therefore precipitation happens to lose this extra moisture.
At abour 30° (N or S), the air (cooler and + denser), therefore less precipitation happen -> deserts
At 60° the air flowing toward the poles collides with cold air moving away from the poles: lots of rainfsll
At the equator, the warmer and more dense air goes up and cools as it goes towards the poles. Its goes back down as rainfall and makes a loop to the equator.
Makes semi-permanent zones of low and of high pression. When the water rises, a low pression zone is created. There are more precipitation, at the equator, then zones where its more dry, and near the UK, its more humid.
Equator (90°): high precipitation
60°: high precipitation
30°: very low precipitations
What are the characteristics of the tropical rain forest? What about its biodiversity?
Insolation: high, sun is directly overhead -> highest solar intensity and not much seasonal change (not much tilt of the planet)
Temperature: high, location -> highest solar intensity with litte seasonal variation.
Water availability: high, over 2500 mm/yr
High NPP -> big producers diversity
Multi-layered forests
Creates many ecological niches -> high animal biodiversity
What are the characteristics of the temperate deciduous forest? What about its biodiversity?
Insolation: medium, Between 40° and 60° of the equator = seasonal variation.
high insolation in summer, low in winter
Temperature: medium, cooler in winter, hot in summer
Water availability: medium/high, between 500 and 1500 mm/yr
Second highest NPP, some forest layering, trees loose leaves in winter (mostly trees of the same size)
-> creates many niches
What are the characteristics of the arctic tundra? What about its biodiversity?
Insolation: low, high latitudes (limits light’s intensity)
Temperature: low all year, (- rate of enzymatic reactions), limits photosynthesis & decomposition.
permafrost: soil that is frozen all-year.
Water availability: low, low annual rainfall and water availability (water is locked as ice)
Low NPP
Growing season = 6 weeks/yr.
No trees, mostly short grasses & bushes. Animals are larger in average.
Low decomposition-> low nutrient cycling -> lots of carbon stored in the permafrost and peat bugs (wet area so cold that no decomposition is happening) of the tundra.
What are the characteristics of the desert? What about its biodiversity?
Insolation: high, at latitude of ~30° from the equator.
Temperature: low and very high. Day: up tp 50°, night: 0°
Water availability: very low. Annual rainfall = less than 250 mm/yr
dry air having lost all moisture because of the precipitations in the tropics.
Lowest NPP,
Lack of water prevents photosinthesis and decomposition.
Difficult to adapt to 2 temperatre extremes,
