Download Ecology

Ecology
Ecology
- the study of the interaction
between living things and their
environment
What is the Biosphere?
• The portion of the earth in which all
living things exist
• Only about 20Km of total diameter of
earth
• From 11km below oceans surface
(hydrosphere) to about 8Km above
earth’s surface (atmosphere)
Consists of two types of factors
• Biotic and Abiotic
• What’s the difference?
• What are some examples of each?
Biotic Factors
•
•
•
•
•
Plants
Animals
Fungi
Protists
Bacteria
Abiotic Factors
• Habitat
• Lakes,
Oceans,
Rivers
• Desert
• Mountains
• Shade, sun
• Rocks
• Climate
• Precipitation,
• Temperature
Oxygen Cycle
• three reservoirs: atmosphere (air),
biosphere (the global sum of all
ecosystems), lithosphere (Earth's crust).
• Water can have areas of hypoxia
(insufficient oxygen)
• The main driving factor of the oxygen
cycle is photosynthesis, which is
responsible for the modern Earth's
atmosphere and life.
Oxygen
• Most free oxygen is in the atmosphere
(O2)
• BUT…most of oxygen mass is found in
the rocks! (It is bound to other things)
• Most atmospheric oxygen comes from
photosynthesis
Oxygen Loss
• Most free oxygen loss is due to
– Respiration and Decay
– Oxygen is taken in and released as CO2
(note the water in usually = the water out)
Also depicted by Energy pyramids
100J
1,000J
10,000J
100,000J
Niches
• Eubacteria/Archaebacteria
– Found in all environments
– Recycle carbon, nitrogen and sulfur
– Decomposers, Pathogens, Nitrogen
fixation, Sulfur cycle, Carbon cycle
(methanogens)
• Protists
– Found in all environments
– Help to make soil, PS (make O2)
– Parasites, diseases
Niches
• Fungi
– All environments, decomposers
– Weathering rocks, soil production
• Plantae
– Photosynthesis, production of O2
– Store food and water
• Animalia
– Make nests, protect offspring, produce
detritus, storage of food and water,
nutrient cycling
Biosphere
• Where all living things are found
Organized into a hierarchy:
• Population: all individuals of a
certain species within a certain
area
• Community: all the populations
of different species within a
specific area
Many subcategories
• Ecosystem: includes a
community and its physical
environment
–Includes both biotic and
abiotic
Many subcategories
• Biome: includes all the
ecosystems in a particular
climate
–Examples:
Individuals have a habitat and a
niche
• Habitat: where an individual
organism lives; its home
– where is yours?
• Niche: the role that organism
plays in its ecosystem
–What is yours?
Relationships between organisms
• Competition: if two individuals
occupy the same niche they
will compete
–Limited resources like?
–Only one will win
Relationships between organisms
• Symbiosis: two organisms
living in close association
–Three types: mutualism,
commensalism and
parasitism
Relationships between organisms
Mutualism: both species benefit
Example?
Why?
Relationships between organisms
Commensalism: one benefits;
the other is neither hurt nor
helped
Relationships between organisms
Parasitism:
one species
benefits at
the other’s
expense
Predator-Prey Relationship
• Predator: organism that eats
another organism; Receives
energy
• Prey: organism that is eaten;
donates energy
• An organism can be both!
To examine ecosystems and
biomes we must add in some
abiotic components
All organisms require Energy
• As one organism eats another
energy moves through
ecosystem
• Forms food chain
• Many food chains make food
web
Food Chain
Food Web
Energy Pyramid
Energy Pyramid
• Producers/Autotrophs: make
food from sunlight or other
inorganic molecules
– examples: plants, algae
and bacteria
Energy Pyramid
• Primary consumers: eat
producers
–Herbivores
–Examples: rabbits, plankton
Energy Pyramid
• Secondary consumers: eat
primary consumers
– Omnivores
Energy Pyramid
• Tertiary (High order)
consumers: eat secondary
consumers
– carnivores
–Larger animals
–Top, or Apex, consumers
are not eaten by anyone
Where does the energy go then?
• Decomposers: bacteria; break
down dead organisms and
return nutrients (nitrogen) back
to the soil for producers to use
• After the decomposers are
done, all the energy absorbed
by the original producers has
been released as heat!
Additionally we need materials
to make up living things
• Biogeochemical cycles!
• Carbon, Nitrogen, Oxygen,
Phosphorous, Water
• All these recycle in unique ways
Biomes of the World
Succession
• the changes an ecosystem
goes through over time
–A kind of “evolution” (simple
 complex!)
Primary Succession
• Begins with rocks
• Pioneer species: Moss and Lichens
Primary Succession
• Primary succession begins in barren areas, such
as the bare rock exposed by a retreating glacier.
• First inhabitants are PIONEER SPECIES
– lichens or mosses
– grown on bare rock
– convert the rock into soil that can support simple plants
such as grasses.
• GRASSES : further modify the soil, which is then
colonized by other types of plants.
– Each successive stage modifies the habitat by altering the
amount of shade and soil composition.
• CLIMAX COMMUNITY: Stable final stage that can
endure for hundreds of years..
Secondary Succession
• Occurs after a disturbance
Secondary Succession
• After a major disturbance,
– fire or flood.
– Farmland that has been plowed
• Secondary succession is similar to
primary succession
– one important difference: primary
succession always begins on a barren
surface,
– secondary succession begins in an area
that already has soil.
–Climax community is the
goal, but is rarely reached
–Disturbances can set the
ecosystem back
• Fires, logging, flood,etc.
Climax community
Limits to an Ecosystem
Thomas Malthus
• Plants and animals produce far more
offspring than can survive,
• Man too is capable of overproducing if left
unchecked. Unless family size was
regulated, man's misery of famine would
become globally epidemic and eventually
consume Man.
Carrying Capacity
• An ecosystem has only enough
resources to support a certain
number of organisms
–This number is the
ecosystem’s Carrying
Capacity
– Non-renewable resources
– Renewable resources
CC controlled by
•
•
•
•
competition
immigration emigration
catastrophic events
seasonal fluctuations in food, water
(available resources)
• hiding places, and nesting sites
(shelter and “family homes
• Population Densities
Stable or Not?
STABLE!
• There will always be “fluctuations”
around the average
What happens as we approach
the carrying capacity?
Competition
• Survival of the fittest
– Numbers cannot go higher because there
are limited resources.
– If an invasive species is present, could
result in extinction or severe lowering in
the numbers of other species due to lack
of predators for the invasive species!
Don’t forget the Human Impact slides!