Life Science-Grade 10 (Term 3-Environmental Studies)
Monday, 29 August 2022
05:32
From Biosphere to Ecosystems
Terminology & Definitions
• The word bio refers to living organisms.
• The biosphere is the part of the earth's surface where life
exists.
• It is made of the:
• Hydrosphere
• Lithosphere
• Atmosphere
Components of the Biosphere
• Surrounding the earth we have a layer of air known as the
Atmosphere. The most important gases are:
• Nitrogen (71-78%) - vital for the formation of proteins.
• Oxygen(21%)- required for all living organisms - cellular
respiration.
• Carbon dioxide(0,03%)- used by plants for photosynthesis
and formation of organic compounds.
• Water Vapour- vital phase in the water cycle as no living
organism can live without it.
• Layers in the Atmosphere:
• Troposphere- layer closest to the surface (10 km above
sea level).
• Stratosphere- 50km above sea level
• Mesosphere- 85km above sea level
• Thermosphere-500km above sea level
• Exosphere- outermost region of a planet's atmosphere.
Monday, 29 August 2022
05:32
From Biosphere to Ecosystems
Terminology & Definitions
• The word bio refers to living organisms.
• The biosphere is the part of the earth's surface where life
exists.
• It is made of the:
• Hydrosphere
• Lithosphere
• Atmosphere
Components of the Biosphere
• Surrounding the earth we have a layer of air known as the
Atmosphere. The most important gases are:
• Nitrogen (71-78%) - vital for the formation of proteins.
• Oxygen(21%)- required for all living organisms - cellular
respiration.
• Carbon dioxide(0,03%)- used by plants for photosynthesis
and formation of organic compounds.
• Water Vapour- vital phase in the water cycle as no living
organism can live without it.
• Layers in the Atmosphere:
• Troposphere- layer closest to the surface (10 km above
sea level).
• Stratosphere- 50km above sea level
• Mesosphere- 85km above sea level
• Thermosphere-500km above sea level
• Exosphere- outermost region of a planet's atmosphere.
