Transcript Document

Ecology Introduction
Ecology is a recent scientific
discipline that has changed over
the years both in the science itself
and how it is perceived by society.
In the 1800’s, German zoologist
Ernst Haeckel stated that ecology
was the study of the relationship
between organisms and
In 1954, ecology was considered to be the
study of the distribution and abundance of
organisms (Andrewartha and Birch 1954).
This definition focused on the biotic factors and
included fluctuations in climate, predators, or
any changes that influence the increase in a
The 1970’s focused ecology on the study of
ecosystems (Odum 1971) with an emphasis on
man as both a positive influence and as a
Man is a part of the biosphere and how he
approaches both short-term and long-term
problems will prove whether he is a good and
wise steward of what God has given him.
Genesis 3:19, 1:28, “be fruitful, and multiply”
and “”subdue. . . and have dominion over” the
earth. “
Ecology also focuses on the flow of
energy throughout a system.
Energy is measured in:
 joules
 calories
 temperature
Some Key Terms
• Population: A group of individuals of
ONE species living in one area. They
interact and interbreed.
• Community: ALL organisms living in one
• Ecosystem: all organisms in an area as
well as the abiotic (nonliving) factors
with which they interact.
Some Key Terms
• Carrying capacity: the maximum
abundance of a population or species
that can be maintained by a habitat or
ecosystem without degrading the
habitat or ecosystem’s ability to provide
for future populations or species
• Limiting factor: a single requirement for
growth available in the least amount
Abiotic Components of Ecosystems
• Rocks, Soil, Temp., Radiation, Wind,
• Water
• Other Factors
– Topography: lay of the land
– Ecological substrate: food sources
– Fires
Biotic Community Ecological
Ecological Relationships
• A group of organisms that can use the
energy in sunlight to convert water and
carbon dioxide into Glucose (food)
• Autotrophs are also called Producers
because they produce all of the food
that heterotrophs use
• Without autotrophs, there would be no
life on this planet
• Ex. Plants and Algae (99% of biomass)
• Chemotrophs
– Autotrophs that get their energy from inorganic
substances, such as salt
– Live deep down in the ocean where there is no
– Ex. Bacteria and Deep Sea Worms
• Organisms that do not make their own food
• Another term for Heterotroph is consumer
because they consume other organisms in
order to live
• Ex. Rabbits, Deer, Mushrooms
• Consumer Levels
– 1. Scavengers/Detritivores – feed on the tissue
of dead organisms (both plants and animals) and
recycle the nutrients for other organisms
• Ex. – Vultures, Crows, and Shrimp
• Consumers
– 2. Herbivores – eat ONLY plants
• Ex. – Cows, Elephants, Giraffes
• Consumers
– 3. Carnivores – eat ONLY meat
• Ex. – Lions, Tigers, Sharks
• Consumers
– 4. Omnivores – eat BOTH plants and animals
• Ex. – Bears and Humans
• Consumers
– 5. Decomposers – absorb any dead material
and break it down into simple nutrients or
• Ex. – Bacteria and Mushrooms
the Transfer (loss) of Energy,
Food Chains,
Food Webs
Transfer of Energy
• When a zebra eats the grass, it does not
obtain all of the energy the grass has (much
of it is not eaten, not everything is
• When a lion eats a zebra, it does not get all
of the energy from the zebra (much of it is
lost as heat)
Transfer of Energy
• The two (2) previous examples of energy
transfer show that no organism EVER
receives all of the energy from the organism
they just ate.
• Only 10% of the energy from one trophic
level is transferred to the next – this is
called the 10% law.(90% is lost as heat)
Trophic Levels
• Energy moves from one organism to another
when it is eaten.
• Each step in this transfer of energy is known
as a trophic level
– The main trophic levels are producers, consumers,
and decomposers
Food Chains
• The energy flow from one trophic level to the
other is know as a food chain
• A food chain is simple and direct
• It involves one organism at each trophic level
Primary Consumers – eat autotrophs (producers)
Secondary Consumers – eat the primary consumers
Tertiary Consumers – eat the secondary consumers
Decomposers – bacteria and fungi that break down
dead organisms and recycle the material back into the
Food Chain
Ecological Pyramids
• Biodiversity
• Food Webs
Food Web
• Most organisms eat more than JUST one
• When more organisms are involved it is
known as a FOOD WEB
• Food webs are more complex and involve lots
of organisms
Food Web
Notice that the
direction the arrow
points 
is the direction of
the energy transfer,
“what ate what”
Food Web
• The total mass of the organic matter at each
trophic level is called biomass
• Biomass is just another term for potential
energy – energy that is to be eaten and used.
• The transfer of energy from one level to
another is very inefficient (10% Law)
Ecological Pyramid
• An ecological pyramid shows the relationship
between consumers and producers at
different trophic levels in an ecosystem
• Shows the relative amounts of energy or
matter contained at each trophic level
• The Pyramid shows which level has the most
energy and the highest number of organisms
Ecological Pyramid
Ecological Pyramid
Ecological Pyramid
most energy?
most organisms?
least organisms?
least energy?
How do different species
interact ?
Species Interactions
• A close and permanent association between
organisms of different species
– Commensalism – a relationship in which one
organism benefits and the other is not affected
• Example: Barnacles on a whale
– Mutualism – a relationship in which both
organisms benefit from each other
• Example: Birds eating pests off a rhino’s back
– Parasitism – A relationship in which one
organism benefits and the other is harmed
• Example: Ticks on a dog
• A close and permanent association between
organisms of different species
– Neutralism – a relationship in which two
different species do not affect each other
– Is neutralism really possible?
Interaction Within the Biosphere
Matter and Energy
Range of Tolerance
Nitrogen Cycle
Habitats/ Niches/ Specialists,
• Niches and Populations
Nitrogen Cycle
Changes in the Biosphere
Remember that all life is in a
‘dynamic equilibrium’
Life forms are constantly changing
their expenditure of energy in response
to changes in their environment
Ecosystems and the Biosphere
are also constantly adapting to
shifts and changes
• Colder than normal winter reduces the eggs
of insects.
• Fewer insects leads to better crops and seed
• Greater seed crop increases the food supply
for small rodents.
• More food leads to more offspring.
• Increased rodents provides more food to
• Fewer insects has a different impact on the
lizards and frogs.
Everything is interconnected!
Biological Rhythms
result in changes in activity
• Diurnal: occur within a 24-hr period
– Nocturnal
– Diurnal
• Seasonal: occur over a 12 mo period
– Some places have only one, some have 2
– Temperate zones have up to 6
• Lunar: occur with changes in the moon
– Affect mostly coastline communities and tide pools
Ecological Succession
• A change in the community in which new
populations of organisms gradually replace
existing ones
• Two types of succession: primary & secondary
– 1. Primary Succession – occurs in an area where
there has been no existing communities and for
some reason (s) a new community of organisms
move into the area. Ex. Volcanic island
Ecological Succession
• A change in the community in which new
populations of organisms gradually replace
existing ones
– 2. Secondary Succession – occurs in an area
where an existing community is partially damaged.
– Ex.: fire, flooding, human agriculture, or industry.
Ecological Succession
• A change in the community in which new
populations of organisms gradually replace
existing ones
– 3. Climax Community – a community that is
stable and has a great diversity of organisms.
Ecological Succession
Man in the Biosphere
Man’s role as Consumer and
Man’s Niche
• Other organisms must find a niche in
their location, or move on.
• Man is unique
• Man can change his environment to
supply his needs.
• It is OK for man to “use” his
environment, depends on “how”