Chapter 5 Flashcards
Process of ecosystems
Cycling chemical elements
Flow of energy
Structure of ecosystems
Made up of two major parts
Living (ecological community)
Non living (physical & chemical environment)
Ecosystem chemical cycling
For complete recycling of chemical elements, several species must interact
Photosynthetic organisms produce sugar from carbon dioxide and water
From sugar inorganic compound they make other organic compounds (protein, woody tissue)
Need decomposers to get back to inorganic compounds
First trophic level
Use energy from the sun and Carbon dioxide from the air tonphotosynthesizes
Green plants, algae and certain bacteria
Called autotrophs
Second trophic level
Organisms that feed on autotrophs
Called herbivores
Third trophic level
Feed directly on herbivores Called carnivores (meat eaters)
Forth trophic level
Carnivores that feed on third-level carnivores
Decomposers
Feed on waste and dead organisms of all trophic levels
Ecosystem energy flow
Movement of energy through an ecosystem from the external environment through a series of organisms and back to the external environment
First law of thermodynamics
Law of conservation of energy
In any physical or chemical change, energy is neither created nor destroyed
Energy merely changed from one form to another
Energy efficiency
As energy flows through a food web, ItI is degraded and less and less is useable
Entropy
Energy must be continually added to an ecosystem in useable form
Biomass
Total amount of organic matter on Earth or in any ecosystem or area
Measured as the amount per unit surface area
Biological production
Capture of useable energy from the environment to produce organic compounds
Gross production
Increase in stored energy before any is used
Net production
Change in biomass over a given time
Three measures used for biological production
Biomass
Energy stored
Carbon stored
Primary production
Autotrophs (&chrmoautotrophs)
Photosynthesize or chemosynthesize
Make their own organic matter room energy source and inorganic compounds
Secondary production
Heterotrophs
Cannot make their own organic compounds and must feed on other living things
Respiration
Use of energy from organic matter by most heterotrophic and autotrophic organisms
Organic matter combines with oxygen
Releases energy, carbon dioxide and water
Use of biomass to release energy that can be. Used to do work
Trophic-level efficiency
Ratio of production of one trophic level to the production of the next trophic level Never very high 1-3% in natural ecosystems 10% may be maximum 90% of all energy lost as heat
Primary succession
Establishment and development of an ecosystem where one did not exist previously
Secondary succession
Reestablishment of an ecosystem following disturbance
Remnants of previous biological community
Patterns of succession
Dunes
Bog
Abandoned farm field
Early succession plant characteristics
Small size
Grow well in bright light
Withstand harshness of environment
Bog
Open body of water with surface inlets but no surface outlets
Succession
Sedge puts out floating runners
Wind blows particles into the mat of runners
Seeds land on runners and germinate
Mat becomes thicker and shrubs wind tress develop
General patterns of succession
An initial kind of autotroph specially adapted to the unstable condition
Typically small
Help stabilize physical environment
Second stage of autotrophs
Still of small statue
Rapidly growing
Seeds that spread rapidly
Third stage
Larger autotrophs, including trees, enter and beigin to dominate the site
Forth stage
Mature ecosystem develops
Increased storage
Organic matter stores chemical elements
Increased rate of uptake
Nitrogen fixation
Decreased rate of loss
Presence of live and dead organic matter slows erosion
Earlier succession species affect what happen later in succession through
Facilitation
Interference
Life history differences
