Unit 1- Ecology Flashcards
System:
- Network of relationships that interact with each other through the exchange of energy, matter or information
- Open System
- Closed System
Open System
○ Receive inputs and produce outputs of both energy and matter
i.e. radiation (energy), carbon output from photosynthesis (matter)
Closed System
○ Receive and produce outputs of energy, but not matter
○ Matter cycles among various parts of the system but does not leave or enter the system
In nature, no system is truly closed
Positive Feedback:
i.e. removal of vegetation to expose soil causes erosion to occur more severely, ice melting to reveal dark surfaces underneath, which absorb even more sunlight and cause additional melting
Steady State:
teady State:
• Stable state that homeostatic systems often demonstrate
• State itself may change over time, even while system maintains ability to stabilize conditions internally
i.e. Earth experiences change in composition over geological time, but is still a homeostatic system
Emergent Properties:
• Characteristics not evident in individual components of a system
• Makes it hard to understand systems by focusing on individual components
• “Whole is more than the sum of its parts”
i.e. Can break down a tree into its parts (branches, roots…etc), but won’t be able to see that a tree is also a habitat
Subsystems:
• Systems rarely have well defined boundaries, can be hard to determine where one ends and another one begins
• Systems form many connections to other systems, and may contain or be contained within other systems
• i.e. rivers flow into great lakes , Great Lake- St. Lawrence River watershed can be one big system, with great lakes and rivers being small systems within it
i.e. System can be whale + fish and plankton eaten by whale ..etc
Geosphere:
• Rock and sediment beneath our feet, in the planet’s uppermost layers
Also known as lithosphere
Atmosphere:
Composed of air surrounding out planet
Hydrosphere:
• All water on the planet (except for water in the atmosphere)
• Cyrosphere
Subsystem consisting of perennially frozen parts of the hydrosphere
Biosphere:
Consists of al the planet’s living organisms
Anthroposphere:
• Subsystem that encompasses parts of environment that are built or modified by humans for human use
i.e. areas where we live, work, study…etc
Ecosystem:
• Consists of all organisms and non living entities that occur and interact in a particular area at he same time
Energy flows and matter cycles among biotic and abiotic components
Ecosystem Ecology:
• Study of energy and nutrient flows among living and nonliving components of systems
• Ecosystems are systems that receive inputs of energy, process and transform that energy while cycling matter internally, and produce a variety of outputs (heat, water flow, animal waste products…etc) that can move into other ecosystems
• Energy and matter are passed among organisms through feeding relationships
• Energy flows through ecosystems in one direction- most come in as radiation from the Sun and exists as heat (energy lost through respiration and heat, not contained in system)
Matter is generally recycled within ecosystems (nutrients remain in system when organisms die)
Ecotones:
Areas where ecosystems meet, in which elements of each ecosystem mix
Biomass:
• Organic material of which living organisms are formed
Formed from radiation from the Sun
Gross Primary Production (GPP):
• Conversion of solar energy to energy of chemical bonds in sugars by autotrophs
Autotrophs use a portion of this production to power their own metabolism by respiration
Net Primary Production (NPP):
• Energy that remains after respiration used to generate biomass by autotrophs
• NPP= GPP- respiration by autotrophs
• Can be measured by organic matter stored by plants after they have metabolized enough for their own maintenance
Energy or biomass available for consumption by heterotrophs
Secondary Production:
Biomass generated by heterotrophs by consuming autotrophs
Productivity:
• Rate at which plants convert energy to biomass in an ecosystem
• Varies based on ecosystem
• Ecosystems with high productivity rates have high net primary productivity
• Freshwater wetlands, tropical forests, coral reefs and algal beds to have the highest NPP
• Deserts, tundra, and open ocean to have the lowest NPP
• In terrestrial ecosystems, NPP increases with temperature and precipitation
In aquatic ecosystems, NPP increases with light and availability of nutrients
Nutrients:
• Elements and compounds that organisms consume and require for survival
Stimulate production by autotrophs, lack of nutrients limits production
Limiting Factor:
• Availability of nitrogen or phosphorus limits plant or algal growth
• When added to a system, producers show the greatest response to whichever nutrient has been in shortest supply
Phosphorus tends to be limiting in freshwater systems, and nitrogen in marine systems
Sustained Yield
Highest rate of use of a resource without decreasing its natural replacement rate
