Ecology Test Review

• Answer: An ecosystem is a group of living things (biotic factors) interacting with each bother and their non -living (abiotic factors) environment
• (see: Ecosystems: What is an ecosystem?)

• Answer: the three abiotic spheres are the lithosphere, hydrosphere, atmosphere.
• (see: Different spheres of an ecosystem)

• The biotic sphere is the biosphere, it contains all living things
• (see: Different Spheres of an Ecosystem)

• The atmosphere is composed of:
  • 78% Nitrogen
  • 21% Oxygen
  • 0.9% Argon
  • Other Gasses Carbon dioxide, water vapor, … etc
• (see: Different Spheres of an Ecosystem, The Nitrogen Cycle, The Water and Carbon Cycle)

Human activities can influence atmosphere composition primarily by increasing gasses like carbon dioxide(CO₂), methane(CH₄) through combustion, deforestation, and agriculture. The gasses trap heat, creating a "greenhouse effect"

• see: Atmospheric Pollution(Air Pollution)

• The lithosphere is the earth's solid outer layer.
• Only the earths crust is considered part of the lithosphere
• (see: The lithosphere)

• The hydrosphere contains the total amount of water in the planet in all forms.
• (see: Hydrosphere)

• The water cycle discusses this
• (see: The Water Cycle?)

• The habitat is the physical area that a species inhabits in its ecosystem
• (see: The physical area that a species inhabits in an ecosystem is called its …)

• A single organism is an individual (1). A group of individuals in the same species living in a specific area is called a population (2). Different populations living together form a community (3)
• The organization of animals.

• An ecological niche is the role an organism plays in its environment. It includes:
  • What it eats
  • Who eats it
  • How it behaves
• (see: Ecological Niche)

• Sustainability is the ability to maintain ecological balance(Sustainability)
• When an ecosystem is sutainable, it is implied that it can survive for a long time without external interaction.

• Biomes are areas that have similar temperature and precipitation patterns. This is called climate.

• A biome is classified by its climate, while an ecosystem is defined by the interactions of abiotic and biotic factors.

• Answer: thermal energy is what warms the earth
• (see: the sun and energy)

• Answer: Radiant energy (solar energy) hits planet earth and is both reflected and absorbed by the atmosphere, lithosphere, and hydrosphere and converted into thermal energy
• (see: the sun and energy; Different Spheres of an Ecosystem)

• 70% of energy is absorbed, 30% is reflected.
• (see: the sun and energy)

• Solar energy is converted into chemical energy that can be stored in plants as glucose
• (see: Photosynthesis equation)

• Thermal energy keeps the surface warm but cannot provide organisms with the energy they need to grow and function
• In order for solar energy to be used by living things it has to be converted into chemical energy. Chemical energy is used by all organisms to perform functions
• (see: Photosynthesis)

• Plants capture the suns energy and turn into chemical energy.
• They take in sunlight, carbon dioxide, and output glucose and oxygen
• THis reaction occurs in the chloroplast
• Photosynthesis

Cellular respiration is when stored energy is released by cells to perform activites.

• Cellular respiration is the opposite of Photosynthesis. It uses the products from photosynthesis and produces the reactants(except for light energy
• (see: Chemical Reaction Notation Anatomy)

A food web shows a linear path of energy flow while a food web is made of multiple interconnected food chains and can depict multiple food sources (see: Food chains and food webs)

A food web illustrates the feeding relationships in an ecosystem

The arrows face in the flow of energy

The highest trophic level(apex predators) is likeliest to have the least population because higher tropic levels have less available energy, which limits the population size they can support (see: Trophic Levels)

The pyramid of numbers displays the number of individuals in a population at each Trophic level (see: There are 3 types of ecological pyramids)

Dry mass is the mass of the organism after all the water has been removed (see: Biomass)

The pyramid of biomass shows the total biomass at each trophic level (see: Energy Pyramids)

The 10% rule dictates that only 10% of energy passes from one trophic level to the next (see: The 10% rule)

Pyramids of numbers and biomass can be inverted and have irregular shapes, while an energy pyramid will always be upright

Transpiration is the biological process of water escaping through a plant's cells, while evaporation is the abiotic process of water changing from a liquid to a gas from any free surface.

Water in gas form is known as water vapor. Another name is steam, which refers to water vapor at or above 100 degrees Celsius.

Condensation is the conversion of a vapor or gas to a liquid (see: Condensation)

Precipitation can come in rain, snow, and hail

Carbon dioxide(CO₂) in the atmosphere is converted into glucose (C₆H₁₂O₆) through photosynthesis. plants and animals release carbon dioxide back into the atmosphere through cellular respiration. (see: The Water and Carbon Cycle)

Methane is a greenhouse gas that traps heat in the atmosphere, causing global warming.

Combustion is the process of burning something.

Carbon from the lithosphere can be returned to the atmosphere through volcanic eruptions, and the combustion of fossil fuels.

Human activity can affect the carbon cycle by releasing stored carbon in fossil fuels to the atmosphere through combustion, this process releases carbon dioxide (CO₂) and other greenhouse gasses at a faster rate than nature can process. Another way that humans influence the carbon cycle is deforestation. The clearing of forests removes trees that act as carbon sinks, reducing CO₂ absorption and increasing atmospheric carbon levels.

Carbon moves through the food chain by consumption. Animals ingest glucose synthesized through photosynthesis that contains carbon.

Carbon from dead animal carcasses is released back into the lithosphere through decomposition

The atmosphere is 78% nitrogen. we can also find nitrogen inside the biosphere as DNA and proteins.

Nitrogen fixation is the conversion of nitrogen in the air (N₂) into ammonia NH₃. This occurs through lightning, and nitrogen fixing bacteria. (see: Nitrogen Fixation)

Nitrification is the conversion of ammonia(NH₃) into nitrates(NO₃). This process is performed by nitrifying bacteria.

Denitrification is when nitrates in the soil are converted back into gaseous nitrogen and released into the atmosphere. It is performed by denitrifying bacteria

Assimilation in the nitrogen cycle is the process where organisms take in abiotic nitrates and convert them into the molecules necessary for life.

Fertilizers convert nitrogen gas directly into ammonia, skipping the process of nitrogen fixation. This increases the amount of usable nitrogen without relying on the natural cycle. More ammonia = more nitrates = more DNA

When too much fertilizer is used nitrates can move from the soil into the groundwater that feeds into lakes and water. The nitrogen stimulates the growth of algae that harm local ecosystems by hogging oxygen.