Food Chains/ Webs
What is an organism that makes its own food called?
What is a producer (autotroph)?
What process occurs when liquid water changes into water vapor?
What is evaporation?
What gas do plants take in from the atmosphere during photosynthesis?
What is carbon dioxide (CO₂)?
Why do living organisms need nitrogen?
Nitrogen is needed to build important molecules such as proteins and DNA.
Which organisms are found at the bottom of an energy pyramid?
What are producers?
In this food chain, grass → rabbit → snake, what is the rabbit?
What is a primary consumer?
What process occurs when water vapor cools and changes into tiny liquid water droplets?
What is condensation?
What process removes carbon dioxide from the atmosphere and incorporates the carbon into glucose?
What is photosynthesis?
Which tiny organisms play an important role in changing nitrogen into forms that plants can use?
What are bacteria?
As you move up an energy pyramid, what happens to the amount of available energy?
The amount of available energy decreases.
In the food chain grass → grasshopper → frog → snake, which organism is the secondary consumer?
What is the frog?
Rain, snow, sleet, and hail are all examples of what part of the water cycle?
What is precipitation?
What process releases carbon dioxide when organisms break down food to obtain energy?
What is cellular respiration?
Plants cannot usually use nitrogen gas directly from the atmosphere. Where do plants obtain usable nitrogen?
From nitrogen-containing compounds in the soil.
About what percentage of energy is typically transferred from one trophic level to the next?
About 10%.
A food web contains grass, rabbits, mice, snakes, hawks, and foxes. If the number of rabbits decreases significantly, which organisms could be directly affected because they depend on rabbits as a food source?
Predators that eat rabbits, such as snakes, hawks, or foxes.
A plant releases water vapor from tiny openings in its leaves. What process is occurring?
What is transpiration?
Humans burn large amounts of fossil fuels. What is the most likely effect on the carbon cycle?
More carbon dioxide is released into the atmosphere.
A farmer adds nitrogen fertilizer to a field. Heavy rain causes the fertilizer to run into a nearby lake. Why could this be a problem?
Excess nitrogen can disrupt the ecosystem and cause excessive plant/algae growth, which can negatively affect aquatic organisms.
A plant contains 10,000 units of energy. Approximately how much energy would be available to the primary consumers that eat the plant?
1,000 units.
10% of 10,000 = 1,000.
In a food chain, the amount of energy available to grasshoppers decreases. What will most likely happen to the organisms that eat the grasshoppers?
Their available energy and food supply will decrease, which could cause their populations to decrease.
A large area of trees is removed from a forest. How could this affect the water cycle?
Less vegetation means less transpiration, which can change how much water vapor enters the atmosphere and affect the movement of water through the ecosystem.
Oceans absorb large amounts of carbon dioxide. If atmospheric CO₂ increases, what is one possible consequence for ocean ecosystems?
Ocean acidification can increase, which can negatively affect marine organisms and disrupt ecosystem stability.
Suppose bacteria that normally convert nitrogen into usable forms become much less common in an ecosystem. What would most likely happen to plants?
Plants could have less usable nitrogen available, making it more difficult for them to grow and build important molecules.
An ecosystem has this energy pyramid:
🌱 Producers: 50,000 units
🐛 Primary consumers: 5,000 units
🐸 Secondary consumers: 500 units
🐍 Tertiary consumers: 50 units
If the producer population suddenly decreases dramatically, which trophic level would most likely be affected first, and why?
The primary consumers, because they depend directly on producers for their food and energy