Ecology

Attributes of Functioning Ecosystems

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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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SpeciationWhen 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 EcosystemsFood 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