Ecosystems
What Organisms Need
The Water Cycle
The Nitrogen Cycle
The Oxygen & Carbon Cycles
100

The living things in this system.

What are biotic factors?

100

Most organisms are made mostly of this.

Water

100

Most of Earth's water is found here.

oceans


Bonus point - What percent?

100

Nitrogen is an important element in this, which all organisms need to survive.

Proteins


Bonus - Nitrogen is also essential in this, passing on genetic info

100

This process is the main source of oxygen in Earth's atmosphere.

photosynthesis

200

Almost all energy on Earth originally came from this.

Sun

200

The layer of gases that surround the Earth is called this. 

atmosphere

200

These 2 things power the water cycle.

Sun and gravity

200

The process that changes nitrogen from a gas into a form organisms can use.

Nitrogen fixation

200

The oxygen cycle involves the change from oxygen to this and back again

carbon dioxide

300

Sunlight and temperature are examples of these.

abiotic factors

300

Earth's atmosphere is composed of oxygen and this.

Nitrogen.

Bonus point - Which gas is more abundant in the atmosphere?

300

Rain, snow, and sleet are examples of this.

Precipitation

300

These unicellular organisms in the soil and water fix nitrogen gas in compounds that other organisms can use

Bacteria

300

This cannot be separated by chemical means

Element


bonus - true or false?  All organisms contain the element carbon.

400

Wind, temperature, and moisture influence the daily _________.

weather conditions

400

Earth's atmosphere protects organisms from what?

the Sun's harmful UV rays

400

Water changes from a liquid to a gas (water vapor) during this process.

Evaporation

400

Some animals obtain the nitrogen they need from these, which have absorbed nitrogen compounds from the soil. 

plants

400

When dead organisms decompose, carbon returns to the ____and is released into the atmosphere.

soil


Bonus - how does carbon appear in the atmosphere?  (in what form?)

500

If you describe the average weather conditions of an area over time, you are describing ___________.

Climate

500

What is made up of rock, water, air, minerals, and the remains of once-living organisms?

Soil

Bonus point - What in the soil recycles nutrients by breaking down the dead organisms?

500

Water vapor changes back into liquid during this process.

Condensation

500

This is how nitrogen is returned from organisms back to the environment.

Bacteria - breaks down dead organisms and waste.

Bonus point - this means nitrogen is returned back to the environment through the ____.

500

Carbon dioxide and other gasses in the atmosphere absorb thermal energy from the sun in this process.

Greenhouse effect

Bonus - what is one "effect" on Earth?