The Distribution of Organisms in the Biosphere

BC Science Probe 10Section 3.1Pages 51-60

The Distribution of Organisms in the Biosphere

• Two important factors in the biosphere that determine if life can exist are:– Average temperature– Average precipitation (rain, snow, etc.)

• The long-term pattern of these two things is called climate.

The Distribution of Organisms in the Biosphere

• Climate on Earth is mostly affected by:– Latitude: the distance from the equator (north or

south in degrees). – Higher latitude = less solar energy.

The Distribution of Organisms in the Biosphere

• Climate on Earth is mostly affected by:– Elevation: the height above sea level.– The atmosphere becomes thinner at greater

elevations and the thinner atmosphere cannot retain as much heat.

The Distribution of Organisms in the Biosphere

• Climate on Earth is mostly affected by:– The distance from a large body of water.– Oceans, seas, lakes, etc.

Factors Affecting Abiotic Conditions

• Solar energy is responsible for the average temperature on Earth.

• This average temperature is much higher near the equator.

Factors Affecting Abiotic Conditions

• Near the equator, the sun’s rays strike the region near the equator more directly.

• This makes the rays more intense, not spread out over a large area.

Factors Affecting Abiotic Conditions

Factors Affecting Abiotic Conditions

• The average temperature is lower when you get closer to the poles because the sun’s rays are spread out over a larger area.

• These rays are not focused, so they are not as intense.

Factors Affecting Abiotic Conditions

• As far as elevation goes:– The higher the elevation, the lower the average

temperature.

Factors Affecting Abiotic Conditions

• The fact that the Earth is tilted at 23½ degrees as it turns on its axis accounts for the seasons.

The Northern Hemisphere

• In the summer, the northern hemisphere is tilted toward the sun which gives it more direct solar rays.

The Northern Hemisphere

• In the winter, the northern hemisphere is tilted away from the sun which makes the solar rays more indirect.

The Northern Hemisphere

• The changes in tilt cause variation in both temperature and precipitation.

• Areas near the equator have very little change in climate over the year.

• Areas farther away from the equator have more variation.

Equator

• The reason that tropical regions near the equator do not get the variations in precipitation and temperature is because this are experiences direct solar rays all year long.

• This means less variation in temperature and precipitation.

Wind and Current

• Water has a higher heat capacity than land.– It needs to absorb a lot of heat energy before the

temperature rises.– It needs to release a lot before cooling.

Wind and Current

• Land will heat up and cool down faster because it does not need to absorb much heat energy to warm up and does not need to release much to cool.

Wind and Current

• So where are the most extreme temperatures to be found?– They will be farther away from the large bodies of

water.– Think about Vancouver winter vs. Edmonton

winter.

Wind and Current

• Where would you notice the most precipitation? On the near (to the water) side of the mountain, or on the far side?– This will happen on the near side.– As the air mass travels over the mountains, it

cools, condenses, and forms precipitation.– On the other side it warms and dries.

Wind and Current

Climatographs

• A climatograph is a graph the shows the changes in temperature and precipitation throughout the year.

World Biomes

• A biome is an area of the biosphere that has a specific climate, temperature, and set of organisms.

• Between biomes is a transitional zone.– The plant life slowly changes to different forms.

World Biomes

• The 8 biomes that we will study in science 10 are:– Tundra– Boreal Forest– Temperate Rainforest– Grassland– Desert– Temperate Deciduous Forest– Tropical Rainforest– Polar Ice

Tundra• Location: – Northern Canada, Asia, Alaska and Europe

• Climate:– Very little precipitation (less than 25 cm/year)– Often below freezing– Permafrost is present

(a layer of permanently frozen soil within a meter of the surface)

Tundra

• Vegetation:– Lichens, mosses and small grasses

• Animals:– Caribou, musk oxen, arctic foxes, ground squirrels,

collared lemmings and ptarmigan.

Boreal Forest

• Location:– To the south of the tundra– Also known as Taiga

• Climate:– 35-75 cm of

rainfall per year

– Dry winter air

Boreal Forest

• Vegetation:– Coniferous forests (pines, spruces, firs)

• Animals:– Wolves, elk, moose, lynx, bears, wolverines, small

rodents and birds.

Temperate Deciduous Forest

• Location:– South of the boreal forest.– Covering regions in southeastern Canada, the

eastern U.S. and large areas of Europe and Asia• Climate:– Higher temperatures than the tundra or taiga– 75-220 cm rain per year

Temperate Deciduous Forest

• Vegetation:– Broadleaf deciduous trees (birches, poplars, oaks,

maples)– Flowers, small trees, shrubs, ferns

• Animals:– Insects, amphibians, reptiles, birds, small

mammals, deer, wolves

Temperate Rainforest

• Location:– British Columbia, New Zealand, Chile– Coastal mountains

• Climate:– 200-350 cm rain per

year– Mild temperatures

Temperate Rainforest

• Vegetation:– Large conifers like cedars with many ferns, berries

and other small plants• Animals:– Raccoons, cougars, bears, amphibians, birds

Grassland• Location:– This biome used to be plentiful in Canada, the U.S.

and Africa, but most has been changed to agricultural land

• Climate:– 25-75 cm of rain per year– Not enough rain to support trees

Grassland

• Vegetation:– Mostly grasses

• Animals:– Rabbits, mice, ground squirrels, hawks, snakes,

coyotes, badgers, foxes, elephants, giraffes, rhinoceros

Tropical Rainforest

• Location:– Found between 30 degrees north and 30 degrees

south latitude• Climate:– 200-450 cm of rain per

year– Temperatures remain

between 20°C-35°C all year

Tropical Rainforest

• Vegetation:– Tall, broad leaf trees

• Animals:– Insects, small mammals, reptiles, birds

Desert

• Location:– North Africa, Central Australia, Southwest U.S.,

Eastern Asia • Climate:– Less than 25 cm rain per year

Desert

• Vegetation:– Sparse vegetation with some cacti and small,

waxy-leaved plants• Animals:– Mostly nocturnal animals with large ears

Polar Ice

• Location:– Arctic and Antarctic regions

• Climate:– Lowest annual average temperature of the biomes

Polar Ice

• Vegetation:– Virtually no natural vegetation

• Animals:– Polar bears, fish-eating seabirds like penguins and

cormorants