APES Unit 1 Study Guide

Sustainability

Ability of a system to survive and function over time.

Sustainable yield

The highest rate at which a potentially renewable resource can be used indefinitely without reducing its availability.

Potentially renewable source

A resource that can be replenished fairly rapidly and must be harvested below the sustainable yield limit.

Open access resource

Resources owned by no one but available to all users free of charge.

Nonrenewable resource

A resource that cannot be replenished at a reasonable rate.

Gross domestic product (GDP)

All goods and services produced within a country during a year.

Per capita GDP

The GDP divided by the total population (per person value).

Developing nations

Countries that have low or moderate industrialization.

Developed nations

Countries that have high industrialization.

Reuse

The practice of using an item more than once before it is disposed of.

Recycling

Processing a resource into a new product.

Closed-loop recycling

Products that can only be recycled into another type of product (lesser quality).

Open-loop recycling

Can be recycled into the same product.

Point source pollution

Pollutants from a single, identifiable source, such as a power plant.

Nonpoint source pollution

Pollutants from many dispersed sources, such as pesticide runoff or automobile exhaust.

Biodegradable

Capable of being broken down by chemical, physical, or biological processes.

Nondegradable

Cannot be broken down.

Ecological footprint

A measure of how much an individual consumes, expressed in an area of land.

External costs

Costs not reflected in the price.

Independent variable (manipulated)

A variable that is not dependent on other variables.

Dependent variable (responding)

A variable that is dependent on other factors.

Controlled variable

Any variable that's held constant in a research study.

Validity (accuracy)

How close a measured value is to the actual or true value.

Reliability (precision)

How close the repeated measurements of a sample are to one another.

Positive Feedback Loop

An input causes the system to change in the same direction, escalating the outcome.

Negative Feedback Loop

An input causes the system to change in the opposite direction from which it is moving.

Abiotic

A nonliving component of an ecosystem.

Biotic

A living (or once living) component of an ecosystem.

Limiting factors

Factors responsible for regulating the population in proportion to its density, such as competition, predation, and diseases.

Limiting factor principle

Too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are optimal.

Trophic level

A step in a food chain.

Autotroph/producer

First trophic level; producers (plants).

Heterotroph/consumer

Second trophic level; primary consumers (herbivores) that must obtain energy by consuming other organisms.

Herbivore

A consumer that eats producers (primary consumers).

Carnivore

A consumer that eats other consumers.

Decomposer

Organisms that secrete enzymes to break down dead organisms and recycle nutrients.

Detritivore (detritus feeders)

Organisms that consume dead organisms.

Biomass

The total mass of all living matter in a specific area.

Ecological efficiency

The percentage of usable energy transferred from one trophic level to the next. (rule of 10%)

Rule of 10%

10% is generally considered to be the ecological efficiency of food chains.

Gross Primary Productivity (GPP)

The rate at which producers convert solar energy into chemical energy.

Net Primary Productivity (NPP)

The amount of chemical energy available after subtracting the energy requirements of the producer.

Oxygen-demanding wastes

Organic wastes that can be decomposed by aerobic bacteria, such as sewage and animal waste.

Biological oxygen demand (BOD)

The dissolved oxygen needed by aerobic decomposers to break down organic materials over a 5-day incubation period at 20°C.

Equation for photosynthesis

6CO2 + 6H2O → C6H12O6 + 6O2.

Equation for cellular respiration

C6H12O6 + 6O2 → 6CO2 + 6H2O.

Eutrophication

Excessive nutrients from fertilizers, sewage, and runoff from farms.

Thermal pollution

Warming of water from power plants and runoff from roads.

Bioaccumulation

The accumulation of substances in an organism.

Biomagnification

An increase in the concentration of a substance in organisms higher up in the