Bio 152 - Energy Flow & Ecosystems

What is an ecosystem?

An ecosystem is all the species that live in an area together with all the components of their physical environment.

• temperature

• nutrients

• environment

What is gross primary productivity (GPP)?

GPP is the total amount of chemical energy produced in an area over a specific time. (GPP = NPP + R)

*This is energy used for cellular respiration by primary producer

What is net primary productivity (NPP)?

NPP is the energy not used for cellular respiration and is available for reproduction and growth, calculated as NPP = GPP - R.

*This is energy used for reproduction and growth

What does biomass represent in an ecosystem?

Biomass refers to the total amount of chemical energy stored in organic material within an ecosystem.

what is an energy flow model show?

it shows how energy moves from autotrophs through other organisms in the form of biomass

• energy lost at each step

What is a food chain?

A food chain describes the species that occupy each trophic level in a particular ecosystem.

What is a food web?

A food web summarizes energy flows and trophic intersections that occur in ecosystems.

what is productivity?

units of biomass produced per unit of area each year

what is efficiency?

a fraction of biomass that is transferred from one trophic level to the next

• 10% of biomass is transferred to next trophic level

What is biomagnification?

Biomagnification refers to the increase in concentration of certain molecules at higher levels in a food chain, often involving heavy metals and persistent organic pollutants (POPs).

• these do not breakdown in the environment and are difficult to digest

How does productivity vary between terrestrial and marine systems?

Productivity is generally higher in terrestrial systems than in marine systems, influenced by factors such as light availability and environmental conditions.

what is the biogeochemical cycle?

a path that an element takes as it moves form abiotic systems through organismsH and back again

How does decomposition rate control cycles?

1. abiotic conditions

2. quality of the detritus as a nutrient source

3. abundance and diversity of detritivores present

What is the global water cycle?

The global water cycle is the movement of water through different systems, including evaporation, precipitation, and groundwater movement.

what is an aquifer?

it is layers of porous rocks, sand, or gravel saturated w/ water

what is a water table?

it is the upper limit of the underground layer of soil that is saturated w/ stored water

what are the human influences on the water cycle?

• depletion of groundwater

• mining freshwater from aquifers

• changes in global weather patterns due to climate change

Where is most of the Earth’s nitrogen?

in the atmosphere

• must be reduced to ammonium nitrate for plant use

what human impact effects nitrogen

fossil fuels - they increase nitrogen which lead to acid rain, depletion of ozone, and climate change

what is the difference between weather and climate?

weather refers to short-term conditions at a specific place and time and climate refers to a long-term average pattern of a region

what is global climate change?

it is the sum of all changes in local temp and precipitation patterns that result from global warming

What is the greenhouse effect?

The greenhouse effect is the trapping of heat between the atmosphere and Earth's surface due to greenhouse gases like CO2 and methane.

What are some possible responses of organisms to climate change?

Possible responses include range shifts, phenology shifts, adaptation, and extinction.

what does it mean for an organism to range shift in response to change?

• Suitable habitat moves toward the poles or toward higher altitudes

• Changes in species interactions and mismatches between species and resources

what does it mean for an organism to phenology shift in response to change?

• Phenology: timing of seasonal events

• Seasonal cues shift -> organisms shift their biological activities to match the season

• Disruption in species.

What does it mean for an organism to adapt in response to a change?

• Change in allele frequencies that favor phenotypes that are best suited to changing conditions

• Sexually reproducing species better able to respond

What does it mean for an organism to extinct in response to a change?

Species unable to adapt to rapidly changing or climate envelope is lost so species has no where to live

What is biodiversity?

Biodiversity is the variety of life in the world or a particular habitat or ecosystem, encompassing genetic, species, and ecosystem diversity.

What is the effect of NPP on land?

• Temperatures can increase photosynthesis

• Drought reduces/ decreases growth

What is the effect of aquatic NPP?

• Higher temperatures= lower NPP

• Stratification= less nutrient mixing = less photosynthesis