Ecosystems & Cycles
What type of ecological relationship benefits both organisms involved?
Mutualism
What is the term for the maximum population size an environment can support?
Carrying capacity.
What is the “tragedy of the commons”?
When people overuse a shared resource because everyone acts in their own self-interest.
What layer of Earth’s atmosphere contains all weather?
The troposphere.
What gas is released in the largest amounts by human activities and contributes most to climate change?
Carbon dioxide (CO₂).
What does NPP stand for in ecology?
Net Primary Productivity
Which type of species usually has many offspring and little parental care: r-selected or K-selected?
r-selected species
Why can clearcutting increase the temperature of nearby streams and rivers?
Because removing trees eliminates shade, causing the water to warm up.
What is the difference between a primary and secondary air pollutant?
Primary pollutants are released directly into the air, while secondary pollutants form in the atmosphere through chemical reactions.
Why does sea level rise as global temperatures increase?
Melting ice and the expansion of warmer ocean water both cause sea levels to rise.
Name one important benefit wetlands provide to ecosystems.
They help filter water or reduce flooding.
A population grows rapidly at first but then begins leveling off as resources become limited. What type of growth is this?
Logistic growth, because the population slows as it approaches carrying capacity
A farmer grows the same crop on the same land every year. What environmental problem can this cause?
Monocropping can reduce soil fertility and increase soil erosion because the same nutrients are removed repeatedly.
Why are cities more likely to experience photochemical smog?
Cities have large amounts of vehicle emissions, sunlight, and pollutants like NOx and VOCs that help smog form.
What is coral bleaching and what causes it?
Coral bleaching happens when corals lose the algae living inside them due to stress from warmer ocean temperatures.
According to the 10% rule, if producers have 1,000 kcal of energy, how much energy reaches the primary consumers?
100kcal
A wildfire destroys part of a forest regardless of how many organisms live there. Is this density-dependent or density-independent?
Density-independent, because the wildfire affects populations no matter their size.
Why is drip irrigation considered more efficient than flood irrigation?
Drip irrigation delivers small amounts of water directly to plants, reducing evaporation and runoff.
How do catalytic converters help reduce air pollution from vehicles?
They convert harmful pollutants into less harmful gases before they leave the exhaust system.
How does ocean acidification harm shell-building marine organisms?
More acidic water makes it harder for organisms like shellfish and coral to build and maintain shells or skeletons.
Why is eating plants usually more energy efficient than eating meat?
A large amount of energy is lost between trophic levels, so eating producers uses fewer resources.
A country has a very wide base on its age structure diagram. What does this tell you about the country’s future population growth?
The country will likely experience rapid population growth because there are many young people entering reproductive age.
Why does eating lower on the food chain usually have a smaller environmental impact than eating large amounts of meat?
A lot of energy is lost between trophic levels, so producing meat requires more land, water, and energy than growing plants.
Explain how acid rain forms.
Sulfur dioxide and nitrogen oxides react with water in the atmosphere to form acids that fall back to Earth as precipitation.
Explain how melting tundra permafrost creates a positive feedback loop that increases global warming.
As permafrost melts, methane and carbon dioxide are released into the atmosphere, which causes more warming and leads to even more melting.