ABEN 198 - Envi Sci Lesson 2

System

assemblage of interacting components forming a functional unit and separated from its surroundings by a boundary

input

any signal from the outside of the system to which it responds

output

the result of the response

surroundings

mass or region outside the system

boundary

imaginary surface that separates the system from its surroundings

open system

closed system

isolated system

types of system

open system

energy and matter freely pass through the boundary

closed system

energy freely passes through the boundary but not matter

isolated system

energy and matter cannot pass through the boundary

ecosystem

an assemblage of living and non-living components elements contained within a boundary such that these elements have functional relationships with each other and can maintain the flow of energy and complete the chemical cycle

a community of organisms and its non-living environment in which matter cycle and energy flows

autotrophic components

self nourishing

chemosynthesizers

autothtophic bacteria

obtain energy by oxidizing inorganic compounds such as ammonia, nitrties, and sulfides and use this energy to synthesize organic compounds

heterotrophic

utiliziation; rearrangement and decomposition of complex materials

need preformed source of organic nutrients

consumers

biophages

organisms which consume other organisms

sapprophages

organisms feeding on dead organic matter

detritus

term that refers to the organic remains in the water and soil that are in the final stage of decomposition

decomposers

they use their digestive secretions to chemically breakdown dead organic matter, including wastes in the external environment

energy

is the capacity to do work

first law of thermodynamics

energy is never created nor destroyed but is transformed from one form to another

second law of thermodynamics

as energy is trasnformed, it degrades or diminishes.

energy transformation is not 100% efficient

nutrient cycle

the second basic principle of ecology

food chain

in an ecosystem there is a pathway of energy that always begin with the producers

it is the sequence of eating and being eaten in ecosystem

represents the flow of energy from one organism to the next

producer

produce food

primary/first-order consumer

herbivore/omnivore

secondary and tertiary consumer

carnivore/omnivore

decomposers

feed on dead organisms

food web

feeding relationship in an ecosystem are never just simple food chains

it shows the various possibilities of the sequence of eating and being eaten in the ecosytem

step 1

annual weeds are found

step 2

perrenial weeds are found

step 3

shrubs are found

step 4

young forest

step 5

mature forest