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Why do only about 10% of energy transfer occurs between trophic levels?
C. Due to energy lost as heat and metabolic processes
What is the primary human activity disrupting the natural carbon cycle?
C. Burning fossil fuels and deforestation
Why is the greenhouse effect potentially dangerous for Earth?
C. It increases global temperatures
Which of the following best describes the role of decomposers in an ecosystem?
Breaking down dead organic matter and recycling nutrients
Which organisms form the base of all food webs?
Producers
How do photosynthesis and respiration work together to maintain atmospheric balance?
They create a cyclical exchange of gases and energy
In the nitrogen cycle, which organisms play a crucial role in nitrogen fixation?
Legume plant roots with specific bacteria
What percentage of atmospheric air is composed of nitrogen?
78%
How do invasive species typically impact native ecosystems?
They disrupt native species by outcompeting for resources
Which of the following best describes how organisms interact with their environment to obtain resources?
Organisms obtain resources from their surrounding environment
What is the primary difference between a food chain and a food web?
Food chains are simple and linear, food webs are complex and interconnected
What would most likely limit a population's growth in an ecosystem?
Lack of space and limited resources
Explain how removing one organism from a food web could affect at least two other organisms in that food web. Give a specific example in your answer.
Removing one organism disrupts the balance of energy flow, causing population explosions in its prey and starvation in its predators
Analyze how invasive species might fundamentally transform an ecosystem's existing ecological balance.
Invasive species can outcompete native species, disrupt food webs, and reduce biodiversity, changing the ecosystem’s balance.
How might population density change in an ecosystem?
Through births, deaths, immigration, and emigration
Describe how climate change might alter predator-prey relationships in a specific ecosystem like a temperate forest.
In a temperate forest, climate change can shift food availability and seasons, causing predators and prey to become out of sync, which can disrupt population balance.
Compare and contrast the potential environmental consequences of natural population cycles versus human-induced population changes in a specific ecosystem.
Natural population cycles usually rise and fall in predictable ways that ecosystems can recover from and stay balanced. Human-induced changes, like overhunting or habitat loss, can cause sudden population drops or overpopulation that disrupt food webs, reduce biodiversity, and create long-term ecosystem damage.
Which combination of factors represents both biotic and abiotic elements in an ecosystem?
Animals and sunlight
What is the primary difference between immigration and emigration?
Immigration means entering a population, emigration means leaving
Explain why decomposers are essential for maintaining ecosystem energy cycles and nutrient availability.
Decomposers break down dead plants and animals, returning nutrients to the soil and water so producers can reuse them. Without decomposers, nutrients would stay locked in dead organisms, disrupting nutrient cycles and limiting energy flow in ecosystems.
Explain how the relationship between nitrogen-fixing bacteria and legumes represents a mutualistic ecosystem interaction
Nitrogen-fixing bacteria live in the roots of legumes and convert nitrogen from the air into a form the plant can use for growth. In return, the plant provides the bacteria with food and a place to live. Both organisms benefit, so this relationship is mutualism.
Compare and contrast the roles of photosynthesis and respiration in maintaining atmospheric gas composition
Photosynthesis removes carbon dioxide from the air and releases oxygen, while respiration uses oxygen and releases carbon dioxide. These opposite processes work together to keep the levels of oxygen and carbon dioxide in the atmosphere balanced.
Describe how apex predators play a crucial role in maintaining ecosystem balance, even with limited energy availability.
Apex predators control the populations of animals below them in the food chain, preventing overpopulation and overgrazing. Even with limited energy available at the top, they help keep ecosystems balanced by maintaining healthy population levels and biodiversity.
Analyze how human activities disrupt energy flow in ecosystems through habitat destruction.
Habitat destruction removes producers and consumers from food webs, reducing the amount of energy entering and moving through an ecosystem. This can break food chains, lower biodiversity, and cause population declines because organisms lose food sources and shelter.
Explain how a keystone species might impact the overall biodiversity of an ecosystem even if it represents a small population.
A keystone species has a large effect on its ecosystem despite a small population because it controls other species or shapes habitats. If it is removed, populations can become unbalanced and biodiversity may decrease, but when it is present, it helps maintain a stable and diverse ecosystem.