Topic 2.1 - 2.2 Flashcards
What is an ecosystem?
A complex system including all living organisms and their environment.
Why are ecosystems considered open systems?
They exchange energy and matter with their surroundings.
What is the primary source of energy in ecosystems?
Sunlight.
What process do producers use to convert sunlight into energy?
Photosynthesis.
According to the law of conservation of energy, what happens to energy in an ecosystem?
It transforms but is not destroyed.
How is energy lost in an ecosystem?
As heat during metabolic processes.
What makes matter cycling in ecosystems different from energy flow?
Matter is recycled, while energy flows and is lost as heat.
What key cycles are involved in matter recycling?
Carbon, nitrogen, and phosphorus cycles.
How does human activity disrupt energy and matter flow in ecosystems?
Through pollution, deforestation, and climate change.
What role does photosynthesis play in the carbon cycle?
It absorbs CO₂, helping regulate atmospheric carbon levels.
What is the second law of thermodynamics in the context of ecosystems?
Energy transformations lead to degradation and heat loss.
How much energy is typically transferred to the next trophic level?
About 10%.
Why do energy pyramids have a pyramid shape?
Due to energy loss at each trophic level.
What is primary productivity?
The rate at which producers create biomass from energy.
Define gross productivity in an ecosystem.
Total energy captured by photosynthesis.
What is net primary productivity (NPP)?
Biomass left after accounting for energy lost in respiration.
What is trophic efficiency?
The percentage of energy passed to the next trophic level.
How is ecological efficiency calculated?
(Energy at higher level / Energy at lower level) × 100.
What are ecological pyramids?
Diagrams showing numbers, biomass, or energy across trophic levels.
How do energy pyramids differ from biomass pyramids?
Energy pyramids always have a traditional pyramid shape due to energy loss.
What is bioaccumulation?
Gradual buildup of pollutants in an organism over time.
How does biomagnification affect predators?
Pollutants increase at each trophic level, impacting higher-level predators.
What are microplastics, and why are they harmful?
Tiny plastic particles that persist in the environment, harming wildlife.
Define maximum sustainable yield (MSY).
The largest sustainable harvest from a species’ stock.
What practices help achieve MSY in forestry?
Sustainable logging and balanced harvesting.
What is the biosphere?
Earth’s system where life exists, comprising individuals, populations, communities, and ecosystems.
What factors affect population size?
Natality, mortality, immigration, and emigration.
What is an ecological niche?
The role and habitat requirements of a species in an ecosystem.
Define intraspecific competition.
Competition between individuals of the same species.
What is interspecific competition?
Competition between different species for the same resource.
Describe parasitism.
A relationship where one organism benefits at the expense of another.
What is mutualism?
A relationship where both species benefit.
Explain the concept of carrying capacity.
Maximum population size an environment can sustain.
What is a J-curve in population growth?
A growth pattern showing rapid growth followed by a sudden drop.
Define an S-curve.
Population growth that stabilizes at carrying capacity.
How do density-dependent factors regulate population size?
They limit growth as population density increases.
Give an example of a density-independent factor.
Natural disasters like floods or fires.
What is a keystone species?
A species that has a disproportionately large impact on its ecosystem.
Describe the concept of r-strategists.
Species that reproduce quickly with many offspring, suited for unstable environments.
What are K-strategists?
Species with fewer offspring, high parental care, suited for stable environments.
What is a clade?
A group consisting of an ancestor and all its descendants.
How does human technology affect carrying capacity?
Increases it by improving resource extraction and adaptability.
What role do decomposers play in ecosystems?
Break down dead organic matter, recycling nutrients.
Define density-dependent limiting factors.
Factors like predation and disease that impact populations based on density.
What is an example of mutualism in nature?
Lichen, a partnership between fungus and algae.
What are autotrophs?
Organisms that produce their own food from inorganic sources.
What are heterotrophs?
Organisms that obtain food by consuming other organisms.
How do chemoautotrophs obtain energy?
By oxidizing inorganic molecules like hydrogen sulfide.
What is secondary productivity?
The rate consumers convert energy from food into their own biomass.
What is Gross Secondary Productivity (GSP)?
Total biomass from food minus energy lost in feces.
Define ecological efficiency in a food chain.
The ratio of energy passed from one trophic level to the next.
What is a food web?
A network showing how energy and matter flow between organisms in an ecosystem.
How does a pyramid of biomass differ in aquatic vs. terrestrial ecosystems?
Aquatic pyramids can be inverted due to fast turnover in primary producers.
What is entropy in an ecological context?
A measure of disorder, increasing with energy transformations in ecosystems.
What is a realized niche?
The actual conditions in which a species lives due to competition and other factors.
What is the role of trophic levels in energy flow?
They represent stages in energy transfer within an ecosystem.
Why is the law of conservation of energy essential in ecosystems?
It explains why energy is transformed but never created or destroyed.
How does energy degradation impact higher trophic levels?
It results in less usable energy as energy moves up the food chain.
What is net secondary productivity (NSP)?
Biomass remaining after accounting for respiration losses in consumers.
Why are density-independent factors important for population dynamics?
They control population sizes regardless of density, such as climate events.
