Chapter 10
Cycles and Patterns in the
Biosphere
Cycles and Patterns
in the Biosphere
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Biogeochemical Cycles
Food Chains
Classification Schemes
Ecosystems and Biomes
Environmental Relationships
Definition: the part of the earth and its atmosphere in which
living organisms exist, or which is capable of supporting life.
A Water Molecule - Sticky Water
Oxygen
80
Hydrogen
1H
Electrons in
outer shell =
Valence electrons
Outer shell = Valence shell
Oxygen is one of most
electronegative of the
92 elements!
O=partial neg
H=partial pos
Vertical Extent of the Biosphere
Periodic Table
Hydrogen – 1st element in
the table – notice the 1!
Oxygen – 8th element
– notice the 8!
Structure - 3 States of Water
Properties of Water
• A molecule is made up of
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1 atom of oxygen and 2
atoms of hydrogen
Pure water has no color,
no taste, no smell
Solid at 0°C or 32°F
Boils at 100°C or 212°F
Contracts to 4°C or 39°F
then expands
Moves down or up capillarity
Biogeochemical Cycles
E
H
O
N
C
• The Flow of Energy
• The Hydrologic Cycle
• The Oxygen Cycle
• The Nitrogen Cycle
• The Carbon Cycle
Definition: an interval during which a recurring sequence of
events occurs; "the never ending cycle of the seasons"
Energy Flow in the Biosphere
Photosynthesis
Insolation
Solar energy and chlorophyll, energy locked up as chemical energy in sugars.
Chem energy then flows through biosphere as animals eat plants or animals.
Hydrologic Cycle
Movement of Water
Most abundant substance; necessary for human life
Solvent and transport system; converts nutrients to
energy and enable repair processes
2 ways found in biosphere: in plant and animal
tissue, and in transit of transpiration & respiration
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Surface to Air
Air to Surface
Air to Air
On and Beneath
Surface
The Carbon Cycle
Carbo + O2 --> CO2 + H2O + energy
Basic element of life; part of all living
things
plants use to make sugars; converted
again to CO2 & returned to
atmosphere
The Oxygen Cycle
Sources:
Atmospheric ozone
Weathering of rocks
Stored in & released
from carbonate rocks
Oxygen is a building block in
most organic molecules
Most is molecular oxygen; plants
decompose
Some atmospheric oxygen;
bound in water molecules that
came from evapotranspiration
Some bound in CO2; released in
animal respiration
Most recycled by photosynthesis
Oxygen Cycle
Determined by 2 things:
• Aerobic respiration of glucose (sugar), which consumes
oxygen and produces CO2
• Photosynthesis, which consumes CO2 & H2O to produce
organic matter (sugars) & molecular oxygen
Photosynthesis takes place
in green plants, whereas
aerobic respiration takes
place in all living organisms.
The oxygen cycle is a biogeochemical cycle
• A biogeochemical cycle is a circuit where a nutrient moves back
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and forth between both biotic and abiotic components of
ecosystems
It’s undissociable from the carbon cycle since it is accomplished
with the carbon dioxyde used for photosynthesis. This cycle
produces oxygen, which, by the respiration burns the carbon
compound produced by photosynthesis to give back carbon gas.
In the end, photosynthesis and respirations are at the origin of the
production and balance of atmospheric gas.
The two mechanisms - CO2 + H2O ---> sugars + oxygen and vice
versa - condition the flow of carbon and oxygen.
This cycle allows us to explain the phenomena of ozone , which is in
the news.
78% Nitrogen
Soil bacteria & blue green algae
Most living organisms need it converted to nitrates
Nitrogen fixation or the Nitrogen Cycle
Once fixed, assimilated by green plants, eaten by
animals, excreted turned to nitrites by bacteria, then to
nitrates by other bacteria and back into the system
The Nitrogen
Cycle
Food Chains
• Food Chains
• Food Pyramids
Food Chain
Food
Pyramid
Ecosystems and Biomes
Ecosystem:
• A community of living and non-living things that work together
• Have no particular size - applied at many scales
– can be as large as a desert or a lake or as small as a tree or a
puddle
• Ex: a terrarium is an artificial ecosystem
– water, water temperature, plants, animals, air, light and soil all
work together
Biome:
• describes areas on earth with similar climate, plants, and animals
• Useful for world distribution patterns
Energy Flow in an Ecosystem