APES Semester Exam

Positive feedback

A change happens, and the system amplifies it, making it worse or stronger

ex: Ice melts → less sunlight is reflected → Earth warms more → more ice melts.

Negative Feedback Loop

A change happens, and the system works to reverse it and bring things back to normal

ex: When the temp gets too high, the thermostat signals the AC to cool things down. Once the desired temp is reached, the AC shuts off

Nitrogen Fixation

Turning nitrogen gas (N₂) from the air into a form plants can use.

Carbon Sink

Anything that absorbs more carbon than it releases.

Transpiration

When plants release water vapor from their leaves into the air.

NPP (Net Primary Productivity)

The amount of energy plants store after using some for themselves

Keystone species

A species that has a big effect on its ecosystem — without it, the ecosystem would change a lot or collapse.

El Niño

A climate event where Pacific Ocean water warms, causing changes in weather worldwide (like more rain in some places, droughts in others).

La Niña

Pacific Ocean water cools, causing different weather patterns (opposite of El Niño).

Albedo

How much sunlight a surface reflects
(High albedo = reflects a lot, like snow; low albedo = absorbs more, like dark soil.)

Coriolis effect

The way Earth’s rotation makes winds and ocean currents curve instead of going straight.

O horizon

The top layer of soil, made mostly of organic material like leaves and dead plants.

A horizon

The topsoil layer below O horizon, rich in minerals and organic matter where plants grow

Contour plowing

Plowing along the land’s curves to reduce soil erosion

Monocropping

Growing the same crop on the same land every year.

IPM (Integrated Pest Management)

Using different methods together to control pests with less harm to environment.

Fracking

A way to get oil or gas by injecting water, sand, and chemicals underground to break rocks and release energy.

Troposphere

The lowest layer of Earth’s atmosphere where weather happens.

Stratosphere

The layer above the troposphere; contains the ozone layer.

Particulate matter

Tiny solid or liquid particles in the air that can harm health.

VOCs (Volatile Organic Compounds)

Gases from chemicals that can cause air pollution and health problems.

Source reduction

Cutting down on waste before it’s made

ex: recycling

Leachate

Polluted liquid that leaks out of a landfill.

Neurotoxin

A poison that harms the nervous system (brain and nerves).

Carcinogen

A substance that can cause cancer.

Biomagnification

Toxins increase in amount as they move up the food chain.

Bioaccumulation

Toxins build up in an organism’s body over time.

Mercury

A toxic heavy metal that poisons water and animals.

Gray water

Used water from sinks, showers, and washing machines (not from toilets).

BOD (Biochemical Oxygen Demand)

The amount of oxygen needed by bacteria to break down organic matter in water.

DO (Dissolved Oxygen)

The amount of oxygen available in water for aquatic life.