Transcript Man & Nature - Coastalzone

Ecology
Attributes of Functioning
Ecosystems
Why are Ecosystems are
Sustainable
Charles Darwin: “The Origin of Species”
• Present forms of life have descended from
previous forms of life…they have evolved
Evolution
• Certain traits allowed some individuals to
adapt better, allowing them to live and
reproduce more successfully
Survival of the Fittest
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Why are Ecosystems are
Sustainable
Charles Darwin: “The Origin of Species”
• These traits were passed on to their
offspring permitting their children to be
more successful
Natural Selection
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Natural Selection works on ...
Species
• Group of organisms
• Similar structural
• Similar functional
characteristics
• Breed with one another
• Have a close common
ancestry
– (common gene pool)
A Population
• A group of organisms
• Of the same species
• Living in the same
geographical area
• At the same time
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Adaptation
• Living organisms have processes by which they
convert food to energy, grow, get rid of waste, and
reproduce. These processes are responsible for
growth, maintenance, reproduction and are called
your metabolism
• An organisms cells function together. One system
must know when to turn on and off, how much of a
substance to produce when to start and when to stop.
The ability or tendency of a body to maintain these
systems in balance over time is called homeostasis
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How Adaptation Works
• Feedback Loops allow an organism to adapt
to their environment or local habitat
• The habitat is the organisms actual living and
non-living surroundings (it’s home)
• A Niche is the function that the organism
serves in the ecosystem or food web
– A rabbit’s niche is a field based consumer
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How Adaptation Works
• Some species specialize in only one type of
habitat (specialists), while others can live in
several habitats (generalists)
• Speciation occurs because one population
may adapt to the particular habitat better than
the other
• The adaptation may give the species a
competitive advantage over other users of the
natural resources
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Speciation
When two population’s of the same species
become separated over a long time, they can
evolve into two different species
– Geographic Isolation: the two populations
become separated geographically
– Reproductive Isolation: the two populations
change so much that they can not successfully
breed together
– Chinquoteaque Horses .vs. Mainland Horses
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Biodiversity
• The processes of Speciation, Adaptation, and
Natural Selection combine to allow different
organisms to take maximum advantage of
different habitats and form their own
individual niches or roles in the environment
• This diversity of organisms and their
roles in the environment is called
Biodiversity
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Ecosystems
• Populations of different species form
communities
• The Biotic (living) and Abiotic (non-living)
components of a community interact together to
form an ecosystem
• An ecosystem can be very small or very large
– a rock and it’s inhabitants in a stream
– a biome
• 33 Biomes, or major types of ecosystems
combine to form the ecosphere - Earth
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Relationships within an Ecosystem
• Predator/Prey: One feeds the other, one
needs the other for food
• Parasitic: One species benefits the expense
of the other
• Symbiosis: cooperative interaction
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Symbiotic relationships
• Commensular: One species benefits with no
effect on the other
• Amensular: One species benefits with a
positive effect on the other
• Mutualism: When both species benefit
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How Ecosystems Work
• Ecosystems are made up of food webs
– A food web consists of a number of interconnected food
chains
• Energy is transferred between trophic levels
through these food webs or chains
• Energy transfers between trophic levels (~10%)
in the form of Biomass (cells & tissue) is minimal
– most of the energy is used by an individual to exist
GPP or Gross Primary Production
– the balance goes toward growth & storage
NPP or Net Primary Production
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Energy Transfer in Ecosystems
Food Chains or Webs consist of different species from
different trophic levels transferring energy (biomass)
• Producers or Autotrophs: things that make their own
food (plants - Primary)
• Consumers or Heterotrophs: things that eat others
for food (Cow, Fox: Secondary, Tertiary)
– Omnivores: eat both plants and animals (human)
– Carnivores: eat heterotrophs or animals (fox)
– Herbivores: eat autotrophs or plants (cow)
– Detrivores: eat wastes and dead things (detritus)
• decomposing and recycling detritus back into useable
organic matter
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Energy Transfer in Ecosystems
Pollutants can bio-accumulate or increase exponentially
in concentration as one moves up the Food chain
This process is because of the law of conservation of
matter: Matter can not be made or destroyed, only
transformed
Environmental Scientists work to control or prevent
negative feedback loops and bio-accumulation
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Ecosystems are Closed Sustainable
Systems
• Ecosystems are efficient in the transfer of energy
between trophic levels
• Competition for food and resources in a trophic level
causes species to adapt
• These adaptations or changes allow the species to
increase their change of survival (speciation)
• Species find habitat offering the best food and shelter
(natural resources) with the least competition
• The fittest individuals within a species survive to
reproduce (natural selection)
• Their offspring have an advantage in exploiting the
natural resources in their trophic level
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