Ecosystems (College Board AP® Biology): Flashcards
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Why do organisms respond to changes in their environment?
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Cards in this collection (42)
Why do organisms respond to changes in their environment?
To maintain homeostasis and improve their chances of survival.
Define behavioral mechanism.
Behavioral mechanism is a response to environmental change characterized by the actions of an organism.
Define physiological mechanism.
Physiological mechanism is a biological process within an organism that helps maintain homeostasis in response to environmental change.
What is the difference between an internal stimulus and an external stimulus?
An internal stimulus arises within the organism (e.g., hormone fluctuations).
An external stimulus comes from the surroundings (e.g., temperature, light, or predators).
Organisms respond to changes in their environment through behavioral and mechanisms.
Organisms respond to changes in their environment through behavioral and physiological mechanisms.
True or False?
Organisms exchange information with one another in response to internal changes and external cues, which can change behavior.
True.
Exchanging information in response to internal changes and external cues can alter behavior, affecting an organism's survival and reproduction and therefore its evolutionary fitness.
Give some examples of organisms exchanging information in response to internal changes and external cues.
The fight-or-flight response in animals
Predator warnings
Plant responses to herbivory
Through which types of signal do organisms communicate?
Visual
Audible
Tactile
Electrical
Chemical
Define intraspecific communication.
Intraspecific communication is communication between members of the same species.
Define interspecific communication.
Interspecific communication is communication between different species.
What do animals use signaling behaviors for?
Establishing dominance
Locating food
Defending territory
Warning of predators
Ensuring reproductive success
Signaling behaviors that change the behavior of other organisms can result in differential success.
Signaling behaviors that change the behavior of other organisms can result in differential reproductive success.
How does fitness relate to innate and learned behaviors?
Fitness favors innate and learned behaviors that increase an organism's survival and reproductive success.
True or False?
Cooperative behavior tends to increase the fitness of the individual and the survival of the population.
True.
Cooperative behaviors such as pack hunting, shared parental care, and swarming raise an individual's fitness and enhance the survival of the population.
Define autotroph.
An autotroph produces organic molecules from simple inorganic substances, acting as a producer in food chains.
Define heterotroph.
A heterotroph relies on organic molecules produced by other organisms, consuming and metabolizing carbohydrates, lipids, and proteins for energy.
Define endotherm.
An endotherm uses thermal energy generated by metabolism to maintain its body temperature within restricted limits.
Define ectotherm.
An ectotherm relies on behavioral adaptations, such as basking in the sun or seeking shade, to regulate its body temperature.
Name four mechanisms endotherms use for thermoregulation.
Shivering
Sweating
Vasodilation
Vasoconstriction
True or False?
Ectotherms generate thermal energy through metabolism to maintain a constant body temperature.
False.
Ectotherms lack efficient internal mechanisms and regulate temperature behaviorally; it is endotherms that use metabolic heat.
A net gain in energy results in energy storage, growth, and increased .
A net gain in energy results in energy storage, growth, and increased reproductive output.
What are the consequences of a net loss of energy for an organism?
Loss of mass
Decreased reproductive output
Eventually, death
Why do some organisms alternate between asexual and sexual reproduction?
In response to energy availability.
Asexual reproduction is less energy-intensive and allows rapid population growth, while sexual reproduction costs more energy but increases genetic variation.
How do photosynthetic and chemosynthetic autotrophs capture energy?
Photosynthetic organisms use sunlight to convert carbon dioxide into carbohydrates.
Chemosynthetic organisms oxidize small inorganic molecules, which can occur in the absence of sunlight or oxygen.
Define saprotroph.
A saprotroph externally digests dead organic matter using enzymes and absorbs the resulting nutrients (e.g. fungi, bacteria).
Approximately how much energy is transferred to the next trophic level, and why is the rest lost?
Only about 10% is transferred.
The rest is lost through respiration, incomplete digestion, and excretion.
True or False?
A pyramid of energy is always pyramid-shaped.
True.
Energy decreases at each higher trophic level, so a pyramid of energy always narrows toward the top.
How does a reduction in the energy available at the producer level affect higher trophic levels?
It reduces the size and number of consumers at all higher trophic levels.
Define biogeochemical cycle.
A biogeochemical cycle is a pathway by which an essential element, such as carbon or nitrogen, moves between the biotic and abiotic reservoirs of an ecosystem.
In an ecosystem, how do energy and matter move differently?
Energy flows through the ecosystem (and is ultimately lost), while matter and nutrients cycle between organisms and the environment.
True or False?
Each biogeochemical cycle demonstrates the conservation of matter.
True.
Matter is not created or destroyed; it is continuously recycled between the abiotic and biotic reservoirs.
Define transpiration.
Transpiration is the process in which plants release water vapor from their leaves, transferring water into the atmosphere.
Name the four main processes that move water through the hydrologic (water) cycle.
Evaporation
Condensation
Precipitation
Transpiration
During , liquid water changes into water vapor and moves from Earth's surface into the atmosphere.
During evaporation, liquid water changes into water vapor and moves from Earth's surface into the atmosphere.
At the highest level of organization, which four processes make up the carbon cycle?
Photosynthesis
Cellular respiration
Decomposition
Combustion
In the carbon cycle, producers remove CO₂ from the atmosphere and convert it into during photosynthesis.
In the carbon cycle, producers remove CO₂ from the atmosphere and convert it into carbohydrates during photosynthesis.
True or False?
In the carbon cycle, the action of decomposers returns carbon to the soil.
False.
In the carbon cycle, decomposers return carbon to the atmosphere as CO₂ when they respire. (Returning elements to the soil is their role in the nitrogen and phosphorus cycles.)
Define nitrogen fixation.
Nitrogen fixation is the conversion of atmospheric N₂ gas into ammonia (NH₃) by nitrogen-fixing bacteria, which may be free-living in the soil or live within the root nodules of legumes.
What happens during nitrification in the nitrogen cycle?
Nitrifying bacteria convert ammonium ions in the soil into nitrates.
What happens during denitrification in the nitrogen cycle?
Denitrifying bacteria use nitrates in the soil during respiration, releasing nitrogen gas back into the atmosphere.
The largest reservoir of nitrogen is the .
The largest reservoir of nitrogen is the atmosphere.
How is phosphate released from rocks in the phosphorus cycle?
Weathering of rocks releases phosphate ions (PO₄³⁻) into the soil and groundwater, where producers can take them up.
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