2.1 Flashcards
Exam 1 Study Materials (20 cards)
What is the hierarchy of organization recognized by ecologists?
Ecologists recognize a nesting organization of life from individuals to the biosphere, focusing on population, community, and ecosystem levels.
Define biosphere.
The total area on Earth where living things are found; the sum of all biomes.
What is a biome?
A distinctive type of ecosystem determined by climate and identified by the predominant vegetation and organisms adapted to live there (e.g., deserts, tropical rainforests, tundra).
Define ecosystem.
All organisms in a given area plus the physical environment with which they interact.
What is the difference between community and population in ecology?
A community includes all populations (plants, animals, and other species) interacting in an area, while a population includes individuals of a single species that interact and interbreed in a specific area.
Why do ecosystems need a constant input of energy?
Energy cannot be reused once used by one organism, so ecosystems need a continuous energy supply.
What are the two fundamental processes in ecosystems?
Matter cycles and energy flow.
What is the carbon cycle?
The movement of carbon through biotic and abiotic components of ecosystems via photosynthesis, cellular respiration, and reservoirs like oceans, soils, and the atmosphere.
How do humans disrupt the carbon cycle?
By increasing atmospheric carbon levels through activities such as burning fossil fuels and deforestation.
What is nitrogen fixation?
The conversion of atmospheric nitrogen (N2) into ammonia (NH3) by bacteria, making nitrogen biologically available to plants.
What is denitrification?
The conversion of nitrate (NO3-) back to molecular nitrogen (N2) by bacteria, releasing it into the atmosphere.
How do human activities disrupt the nitrogen cycle?
By introducing excess nitrogen into ecosystems through fertilizer use and industrial processes.
What is the phosphorus cycle?
The movement of phosphorus from rock to soil or water, to organisms, and back to soil, essential for ATP and nucleic acids.
How do human activities disrupt the phosphorus cycle?
By releasing more phosphorus through mining and fertilizer use.
What is a limiting factor?
A critical resource whose supply determines the population size of a species in a given ecosystem.
Define range of tolerance.
The range of a limiting factor within which a species can survive and reproduce.
What are producers?
Organisms that convert solar energy to chemical energy via photosynthesis.
What are consumers?
Organisms that obtain energy and nutrients by feeding on other organisms.
What is the main lesson learned from the Biosphere 2 experiment?
Earth is truly irreplaceable, and its delicate balance must be protected.
Why are biomes influenced by precipitation and temperature?
These factors determine the vegetation and organisms adapted to live in a specific biome.
