Science Unit 4: Ecology

The Earth’s Four Spheres

Biotic vs Abiotic

• Biotic factors are living things within an ecosystem (ex: animals, plants, fungi, bacteria, once living, part of living)

• Abiotic factors are the non-living components of an ecosystem (ex: air, water, soil, rock)

• An ecosystem is the relationship between biotic and abiotic factors (ex: humans need oxygen in the air to make energy)

The Atmosphere

• The layer of gases surrounding the Earth

• It’s composition is 78% nitrogen, 21% oxygen, and 1% other gases

• Without the atmosphere, we wouldn’t have oxygen for energy or temperature control to keep us from freezing

The Lithosphere

• Earth’s rocky, outer shell

• Consists of rocks, and minerals that make up the mountains, ocean floors, and the rest of Earth’s solid landscape

• 50-150 km thick

The Hydrosphere

• All of Earth’s water

• Includes things like oceans, lakes ice, ground water, rain, water in living things

• Can be on, above, or below the Earth’s surface

The Biosphere

• The “zone” around Earth where life can exist within the other three spheres

Climate Change and Greenhouse Gases

• Greenhouses are glass structures which trap heat to grow plants in colder temperatures

• Greenhouse gases are gases that exist in the atmosphere that trap heat on Earth (this is good)

• Too much greenhouse gases cause too much of the heat from the Sun to be trapped in the atmosphere (this is bad)

• Some examples of greenhouse gases are:

  • Water (H₂O)

  • Carbon dioxide (CO₂)

  • Methane (CH₄)

  • Dinitrogen monoxide (N₂O)

How Plants and Animals Get Energy

Photosynthesis: producers only

• Producers can’t eat other organisms for food

• They use the energy from the Sun to join carbon dioxide and water together to make sugars (food) and oxygen

• Word formula: CO2 + H2O + Sunlight → Sugar + O

Cellular respiration: producers and consumers both

• Producers and consumers need to create energy from the food that they make or eat

• They use oxygen to break down sugars to create carbon dioxide, water, and energy

• Word formula: O + sugar → CO2 + H2O + ATP

Cycles of Matter

The Carbon Cycle

• Carbon dioxide that is produced from plant and animal cellular respiration gets taken in during photosynthesis

• This is part of the carbon cycle. Remember that matter can’t be created or destroyed

• Some carbon gets returned to the soil through the decomposition

• Sometimes carbon gets stuck in the earth and turns into fossil fuels over the course of millions of years

• Carbon dioxide can enter the atmosphere through burning fossil fuels in factories, driving cars, or generating electricity.

• Carbon dioxide can also enter the atmosphere during animal and plant cellular respiration

Water Cycle: A Recap

• Evaporation: liquid water changes state into gas

• Condensation: gaseous water turns into liquid

• Precipitation: water from the atmosphere reaches earth (can be rain, snow, or hail)

Ocean Acidification

• The ocean absorbed 50% of all CO2 from our emissions because it is a natural carbon sink that stores carbon and carbon containing chemical compounds

• The CO2 weakens clams and crab shells and causes disruptions in the food chain

• The CO2 turning the ocean acidic could eventually dissolve shells of said animals

Food Chain and Food Web: Vocabulary

• Autotroph: an organism that produces it’s own nutrients

• Herbivore: an organism that exclusively consumes plants

• Primary carnivore: the first carnivore in a food chain when following the flow of energy

• Secondary carnivore: the second carnivore in a food chain when following the flow of energy

• Primary consumer: the first consumer in a food chain when following the flow of energy

• Secondary consumer: the second consumer in a food chain when following the flow of energy

• Tertiary consumer: the third consumer in a food chain when following the flow of energy (tertiary means third)

• Trophic levels: the level of an organism in an ecosystem depending on it’s feeding position along a food chain

• Original energy source: the source of all energy that will flow through the food chain or food web (most of the times, this energy source is the Sun)

• Producer: an organism that doesn’t need to rely on other organisms for food, because it can make its own food.

Factors Affecting Sustainability

What Does Sustainability Mean?

Sustainability means to maintain balance in an ecosystem so that it can survive

Air and water quality are affected by the following:

• Pollution

• Pesticides/fertilizers

• Run-off from farms

• Garbage disposal

Soil health is affected by the following:

• Acidity

• Temperature

• Changes in soil nutrients

• Amount of water

Biodiversity is affected by the following:

• Hunting

• Climate change

• Monoculture

• Invasive species

Succession

A series of changes in an ecological community over time. Primary successions are when plants and animals colonize a barren land (where no life has ever existed). Soil needs to be made.