The benthic zone refers to the deeper zone of water that sunlight can’t easily reach
Plants near the shoreline are more suited for that section of the lake because the easy access to sunlight allows them to photosynthesize and acquire energy
The process by which plants use sunlight, water, and carbon dioxide in order to produce sugar and oxygen
Deforestation and fossil fuel extraction
These processes can “add” carbon into the atmosphere
Matter cannot be created or destroyed; however, when fossil fuels are dug up and burnt, the carbon that was previously stored in the fossil fuels (away from the atmosphere) becomes a part of the atmosphere, increasing the concentration of carbon that is cycling throughout the rest of the carbon cycle
These serve as the largest reservoir of phosphorus
The atmosphere is NOT included in the phosphorus cycle
The phosphorus cycle moves relatively slowly
Limiting factor
The limiting factor of a biological system is the component that is the most scarce
Since phosphorus is relatively scarce in many ecosystems, it is the “factor” that often “limits” a biological system from occurring as frequently as it would if phosphorus were in abundance
When runoff water travels along a permeable surface, it can flow into the ground and charge a groundwater source
The construction of cities, where impermeable concrete/pavement is used in urban development, has the potential to threaten aquifers and groundwater because it prevents water from refilling these water sources
The water continues to travel as runoff instead of seeping into the ground
Reservoir
The largest reservoir of water is the ocean
Ice caps and groundwater/aquifers also act as water reservoirs/storers
Solar energy
The hydrologic cycle is powered by the sun
1.8 Primary Productivity
Gross Primary Productivity
The RATE at which an ecosystem’s producers convert energy from the sun into stored chemical energy
APES rubrics sometimes specify that the term ‘rate’ has to be included in descriptions/discussions related to primary productivity, so including the word ‘rate’ increases your chances of receiving credit on FRQ’s
Net Primary Productivity
The rate at which an ecosystem’s producers convert energy from the sun into stored chemical energy MINUS the rate at which an ecosystem’s producers use that energy for respiration
Energy cannot be created or destroyed, but it can be converted into different forms of energy
Autotrophs
Producers are also known as autotrophs; the term refers to organisms that get their energy from converting solar power into (stored) chemical energy
1.10 Energy Flow and the 10% Rule
10% Rule
When energy is transferred from one organism to another, only 10% of an organism’s energy is able to make it to the organism one trophic level above it
Most of the energy that an organism has is used for life processes (such as respiration) and/or lost as heat energy
Primary producers, such as plants, only convert 1% of solar energy into stored chemical energy for their respective trophic level
Tertiary consumers
In most ecosystems, there’s a lesser amount of species/organisms at higher trophic levels (such as tertiary consumers) because that organism would have to consume a large amount of prey in order to get enough energy for it to survive (since so little energy makes its way that high up the energy pyramid)
1.11 Food Chains and Food Webs
Energy arrows
In food chains and food webs, energy arrows depict the direction that the ENERGY is traveling in
For instance, if a mouse eats grass, then the arrow would be drawn FROM the grass TO the mouse because the energy in the grass is being converted into energy for the mouse
While food chains depict a single “chain” of energy flow (such as grass -> mouse -> snake -> eagle), food webs depict a variety of interactions and multiple chains of energy flow
Some organisms can be classified as both secondary and tertiary consumers
For example, the hawk in the food web above can be classified as both a secondary consumer (grass -> rabbit -> hawk) and a tertiary consumer (grass -> grasshopper -> mouse -> hawk)
