INTRODUCTION TO INTRODUCTION TO ECOLOGYECOLOGY

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ScienceScience• from the Latin scientia, meaning "knowledge" or from the Latin scientia, meaning "knowledge" or

"knowing“"knowing“

• any systematic knowledge-base or prescriptive any systematic knowledge-base or prescriptive practice that is capable of resulting in a practice that is capable of resulting in a prediction or predictable type of outcomeprediction or predictable type of outcome

• is a processis a process

• is a method of learning more about the worldis a method of learning more about the world

• constantly changes the way we understand the constantly changes the way we understand the worldworld

The Scientific MethodThe Scientific Method

Define the Define the ProblemProblem1 Gather Gather

DataData2 Formulate Formulate HypothesiHypothesi

ss3

Test Test HypothesiHypothesi

ss4 Draw Draw

ConclusioConclusionn

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EcologyEcology

• Greek word “oikos” – house & “logos” – study of

• The study of the relationships / interactions / interconnectedness /

interdependence

between organisms and their environments

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Ecosystem Ecosystem

• A A community of interdependent community of interdependent organisms along with the organisms along with the inorganic components of their inorganic components of their environmentenvironment

• An interacting collection of An interacting collection of organisms (biotic) and the abiotic organisms (biotic) and the abiotic factors that affect themfactors that affect them

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Abiotic factorsAbiotic factors

• The non-living components of an The non-living components of an ecosystemecosystem

• Consists of the elements which Consists of the elements which may be found in the environmentmay be found in the environment

• Physical and Chemical factors that Physical and Chemical factors that influence living organismsinfluence living organisms

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Physical factorsPhysical factors

• Sunlight and shadeSunlight and shade

• Temperature and windTemperature and wind

• Amount of precipitationAmount of precipitation

• Altitude and latitudeAltitude and latitude

• Nature of soilNature of soil

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Chemical factorsChemical factors

• Salinity of waterSalinity of water

• Level of dissolved OLevel of dissolved O22 and other and other

gasesgases

• Level of plant nutrientsLevel of plant nutrients

• pH of soil and waterpH of soil and water

• Level of natural or artificial toxic Level of natural or artificial toxic substancessubstances

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Biotic factorsBiotic factors

• The organisms in an ecosystem are The organisms in an ecosystem are either:either:Autotrophs (producers)Autotrophs (producers)Heterotrophs (consumers)Heterotrophs (consumers)

• Autotrophic organisms may be Autotrophic organisms may be photoautotrophic or chemoautotrophicphotoautotrophic or chemoautotrophic

• The heterotrophs include humans, The heterotrophs include humans, animals and microorganismsanimals and microorganisms

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Autotrophs Autotrophs

• Photoautotrophs possess chlorophyll Photoautotrophs possess chlorophyll that captures energy and convert COthat captures energy and convert CO22, , HH22O to sugar through photosynthesisO to sugar through photosynthesis

• Chemoautotrophs are bacteria that Chemoautotrophs are bacteria that obtain energy from the oxidation of obtain energy from the oxidation of inorganic compounds such as inorganic compounds such as ammonia, nitrites and sulfidesammonia, nitrites and sulfides

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HeterotrophsHeterotrophs

• Heterotrophic organisms get their Heterotrophic organisms get their energy and source of pre-formed energy and source of pre-formed nutrients by consuming tissues of nutrients by consuming tissues of other organismsother organisms

• Consumers are classified according to Consumers are classified according to the type of food they eatthe type of food they eat

HerbivoresHerbivores (plant eaters) – feed directly on (plant eaters) – feed directly on producersproducers

CarnivoresCarnivores (meat / flesh eaters) – feed on other (meat / flesh eaters) – feed on other consumersconsumers

OmnivoresOmnivores – eat both plants and animals – eat both plants and animals

Decomposers – simple oorganisms that obtain their energy from the chemical breakdown of dead organisms as well as from animal and

plant waste products

Detrivores – complex / multi-cellular organisms that feed on waste matter, breaking down organic material into inorganic substances that then can become available

to the biosphere in the form of nutrients for plantson dead organic matter

ScavengersScavengers – feed on dead – feed on dead organisms that were killed by other organisms that were killed by other

organisms or died naturallyorganisms or died naturally

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HomeostasisHomeostasis • from Greek: ὅμος, hómos, "similar";

and ιστημι, histēmi, "standing still”

• is the property of a system, either open or closed, that regulates its internal environment and tends to maintain a stable, constant condition

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Control MechanismControl Mechanism