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BIOSPHERE AND BIOMES
14 AUGUST 2013
Lesson Description
In this lesson we:
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Discuss the concept of the biosphere
Look at the interconnectedness with components of the global ecosystem: lithosphere,
atmosphere and hydrosphere
Discuss the terrestrial and aquatic biomes of Southern Africa
Key Concepts
The Biosphere
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The part of the planet that supports life e.g. atmosphere(air), lithosphere (land) and
hydrosphere(water
The Lithosphere
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The lithosphere is the solid, rocky crust covering entire planet. This crust is inorganic and is
composed of minerals. It covers the entire surface of the earth.
This is where terrestrial organisms live
The shape of the land surface is called its topography.
A thin layer of soil supports life. Soil is formed from weathered rock
The soil provides plants with nutrients and water to support all the organisms in a food chain
The Atmosphere
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The atmosphere is the body of air which surrounds our planet. Most of our atmosphere is
located close to the earth's surface where it is most dense. The air of our planet is 79%
nitrogen and just under 21% oxygen; the small amount remaining is composed of carbon
dioxide and other gasses.
The atmosphere consists of five layers of gases that support life and protect us from harmful
radiation from the sun
The Hydrosphere
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The hydrosphere is composed of all of the water on or near the earth. This includes the
oceans, rivers, lakes, and even the moisture in the air. Ninety-seven percent of the earth's
water is in the oceans. The remaining three percent is fresh water; three-quarters of the fresh
water is solid and exists in ice sheets
Aquatic organisms depend on the hydrosphere for life
Interconnections of the Spheres
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The lithosphere, hydrosphere and atmosphere form the biosphere.
The soil, water and air support life on earth.
Life on earth is linked in each of the three spheres.
All four spheres can be and often are present in a single location. For example, a piece of soil
will of course have mineral material from the lithosphere. Additionally, there will be elements
of the hydrosphere present as moisture within the soil, the biosphere as insects and plants,
and even the atmosphere as pockets of air between soil pieces.
There are two components to the biosphere
o A biotic or living component –
animals, plants microorganisms
etc.
o An abiotic or non-living
component – water air
temperature, soil etc.
o The biotic and abiotic factors of the
biosphere form the global
ecosystem
Living organisms are not evenly distributed
throughout the biosphere.
Scientists have divided the earth into
regions according to their climate, soil,
plants and animals that live their – these
regions are called biomes
Biomes are sub-divided into ecosystems.
Ecosystems are communities of
organisms that interact in a particular
environment.
An organism lives in a certain place where
it gets its food, space and where it
reproduces – this is called its habitat
Scientists divide biomes into :
o Terrestrial biomes that occur on land – grasslands, savannah, fynbos
o Aquatic biomes - marine, wetlands, coastal
South African Biomes – Aquatic
Marine and Coastal Biomes
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Include – oceans, coral reefs and estuaries
Biomes include salty water.
Algae live in the water and produce oxygen and food
South African marine biome contains 12% of the worlds fish species. Our coastline is 3000km
long
Water on the east coast is warm because of the warm Indian current and the water on the
waest coast is cold because of the Benguela current.
The west coast water are rich in nutrients which provides food for plankton and fish
Organisms
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Plankton- phytoplankton (algae), zooplankton (microscopic crustaceans) – fish and large fish
– sharks, dolphins, whales – animals living on the bottom – crabs, oysters, sponges, lobster
etc.
Organisms have to endure various abiotic factors:
o Saltiness
o Ocean currents and waves
o Oxygen variation
o Variations in sunlight
o Depth and temperature of water
o Concentration of nutrients
Coral Reefs
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Shallow waters off the northern coast of
Kwa-Zulu Natal
Coral reefs are formed from calcium
carbonate of tiny corral animals
Large biodiversity
Animals – micro-organisms, invertebrates,
fish, sea urchins, sea-stars, octopusi
Open Sea Zone
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Open ocean
Temperature is generally cold
Plankton main food provider for fish, dolphins and whales
Wetlands
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Area of land which is covered predominately by shallow water.
Include mountain springs, marshlands, flood plains, estuaries to swamp forests that are linked
by river and streams.
Rich in biodiversity:
o Birds
o Large amount of carbon
o These wetlands share common and
important functions in river catchments
by providing a regular water supply, by
filtering the water naturally
o By reducing the effects of floods and
droughts.
Estuaries
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Are areas where freshwater of streams or rivers
meet with the salt water of the sea
Water conditions, temperature and salt content,
change constantly with the tides
Rich in nutrients
Plants – algae, seaweed, marsh grass and
mangroves
Animal – prawns, sponges, mussels, barnacles,
crabs
Important Terms
Biosphere
Lithosphere
Atmosphere
Hydrosphere
Ecosystems
Biodiversity
Biomes
Endemic
Aquatic
Terrestrial
Estuary
Questions
Question 1
Study the map below where South Africa’s terrestrial biomes are indicated with the letters A to G and
answer the questions that follow
a.) Define the term biome
b.) Identify the biomes A-F
c.) Which biome is a main tourist attraction during spring, when the whole area is covered with
flowers?
d.) Which biome includes one of the world’s richest floral kingdoms?
e.) Which biome attracts tourists to its many game farms?
f.) Which biome is the largest?
g.) Which biome will you find the following plant species?
i.
ii.
iii.
iv.
Vygies, quiver trees
Yellowwood and stinkwood
Mopani and baobab
Proteas, ericas and reeds
Links
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Maps - edlist.sanbi.org/stats.php
http://kruger2canyons.com/learningcentre/kruger_biomes.php
www.youtube.com/results?search_query=south+african+biomes&oq=south+african+biomes&
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