Unit 1- Ecology

Question 1

System:

Answer 1

• Network of relationships that interact with each other through the exchange of energy, matter or information
  
  • Open System
  • Closed System

Question 2

Open System

Answer 2

○ Receive inputs and produce outputs of both energy and matter
i.e. radiation (energy), carbon output from photosynthesis (matter)

Question 3

Closed System

Answer 3

○ 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

Question 4

Positive Feedback:

Answer 4

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

Question 5

Steady State:

Answer 5

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

Question 6

Emergent Properties:

Answer 6

• 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

Question 7

Subsystems:

Answer 7

• 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

Question 8

Geosphere:

Answer 8

• Rock and sediment beneath our feet, in the planet’s uppermost layers
Also known as lithosphere

Question 9

Atmosphere:

Answer 9

Composed of air surrounding out planet

Question 10

Hydrosphere:

Answer 10

• All water on the planet (except for water in the atmosphere)
• Cyrosphere
Subsystem consisting of perennially frozen parts of the hydrosphere

Question 11

Biosphere:

Answer 11

Consists of al the planet’s living organisms

Question 12

Anthroposphere:

Answer 12

• 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

Question 13

Ecosystem:

Answer 13

• 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

Question 14

Ecosystem Ecology:

Answer 14

• 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)

Question 15

Ecotones:

Answer 15

Areas where ecosystems meet, in which elements of each ecosystem mix

Question 16

Biomass:

Answer 16

• Organic material of which living organisms are formed

Formed from radiation from the Sun

Question 17

Gross Primary Production (GPP):

Answer 17

• 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

Question 18

Net Primary Production (NPP):

Answer 18

• 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

Question 19

Secondary Production:

Answer 19

Biomass generated by heterotrophs by consuming autotrophs

Question 20

Productivity:

Answer 20

• 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

Question 21

Nutrients:

Answer 21

• Elements and compounds that organisms consume and require for survival
Stimulate production by autotrophs, lack of nutrients limits production

Question 22

Limiting Factor:

Answer 22

• 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

Question 23

Sustained Yield

Answer 23

Highest rate of use of a resource without decreasing its natural replacement rate