Levels of Organization/Energy Flow
This level includes living and nonliving things
Ecosystem
After a wildfire, what type of succession occurs?
Secondary succession occurs after a wildfire because the fire destroys existing vegetation but leaves the soil, nutrients, and seed bank intact, allowing for rapid re-colonization
What two main processes help the carbon cycle?
Cellular Respiration and Photosynthesis
A relationship where one benefits and the other is unaffected:
Commensalism
A limiting factor is:
Any biotic (living) or abiotic (non-living) environmental resource or condition that restricts the size, growth, abundance, or distribution of a population within an ecosystem.
A scientist studies only a herd of deer in a forest. What level is this?
Population
Why are pioneer species important?
Pioneer species are essential because they are the first organisms to colonize barren or disturbed environments, initiating ecosystem development. They build soil, enhance nutrient cycling, prevent erosion, and create habitable conditions for more complex plant and animal life.
Other than cellular respiration what is the biggest contributor to atmospheric CO2?
Burning Fossil Fuels (combustion)
Aphids are little sap-sucking insects that secrete honeydew, a sugary liquid that is the waste product of their diet. Ants feed on the honeydew by squeazing the aphids with their antennae. The ants serve as protectors.
Mutualism
Density-independent factors include:
Density-independent factors in biology are environmental, usually abiotic (non-living), factors that affect population size regardless of how dense the population is. (hurricanes, earthquakes)
Producers in an ecosystem store 20,000 kJ of energy. How much energy is available to secondary consumers?
200 kJ
Explain why biodiversity increases during succession.
Biodiversity increases during ecological succession because the environment becomes more complex and habitable over time
Fertilizer runoff enters a lake. How is the lake affected?
Extra nitogen in the water leading to algal blooms (less oxygen and blocks sunlight from the water below) causing the fish and other organisms to die.
Two species rely on the same food source. Predict what will happen to both populations.
They will engage in competition, which generally results in reduced fitness, lowered reproduction, and reduced population growth for both species.
A population grows quickly and then levels off. Why does growth stop?
The environment lacks sufficient resources, such as food, water, and space, to support a larger population
Predict what would happen to an ecosystem if producers suddenly decreased.
Less primary consumers, less secondary consumers, less tertiary and apex predators
Why do invasive species outcompete native species?
No natrual predators
Nitrogen Fixing bacteria do what?
Change unusable atmospheric nitrogen to be changed into useable nitrogen for the plant
A parasite infects a host population. What happens to the host population over time?
reduced density, lower reproduction rates, and higher mortality, often leading to population regulation or, in severe cases, localized extinction
A disease kills half of a population. What type of limiting factor is this?
Density-dependent factor
Why are defining levels of organization important to scientist?
An ecosystem is a dynamic whole where lower-level changes (e.g., individual behavior) ripple upwards, and higher-level conditions (e.g., climate) dictate lower-level possibilities. WHAT IS INTEACTING TOGETHER AT DIFFERENT LEVELS.
A dam reduces water flow in a river. Predict the effect on organisms
Reduced water flow from dams will cause blocked migration for fish (e.g., salmon), lower oxygen levels, warmer water temperatures, reduced food sources, and increased mortality from high sediment or pollutant exposure
Explain how decomposition connects BOTH the carbon cycle and nitrogen cycle.
Decomposition breaks down dead organic matter, which releases stored carbon into the atmosphere as carbon dioxide and converts organic nitrogen into ammonia and or ammonium which go back into the soil.
Explain how predator-prey relationships can help maintain ecosystem stability.
Predator-prey relationships stabilize ecosystems by maintaining balance, where predator numbers control prey populations, preventing overgrazing and habitat degradation
A population exceeds carrying capacity. Predict TWO possible outcomes.
Reduction in birth rates and increase in mortality rates.