3 Flashcards
(15 cards)
What does the 2nd law of thermodynamics imply for energy flow in ecosystems?
Energy decreases at each trophic level as it is lost as heat during transfers between organisms.
What is ecological efficiency?
The percentage of usable energy transferred as biomass from one trophic level to the next.
What is a trophic cascade?
A chain reaction of ecological effects triggered by the removal or decline of a top predator or keystone species.
What role do keystone species play in ecosystems?
They help determine the types and numbers of species in a community and maintain ecosystem structure.
What happens if keystone species are lost?
It can lead to an extinction cascade and ecosystem instability.
Define intrinsic rate of increase (r).
The rate at which a population would grow if it had unlimited resources.
What is carrying capacity (K)?
The maximum number of individuals an environment can support indefinitely.
Distinguish between exponential and logistic growth.
Exponential growth creates a J-curve with unchecked growth; logistic growth levels off into an S-curve at carrying capacity.
What is ecological succession?
The gradual change in species composition in an area over time.
Difference between primary and secondary succession?
Primary occurs in lifeless areas without soil; secondary occurs where soil remains after disturbance.
What is ecosystem resilience?
The ability of an ecosystem to recover from a disturbance.
How does biodiversity support ecosystem stability?
High species diversity increases ecosystem resilience, sustainability, and resource use efficiency.
Where is species diversity highest globally?
In tropical regions, particularly tropical forests and coral reefs.
What factors contribute to high tropical biodiversity?
High solar energy, stable climate, abundant resources, and long uninterrupted evolutionary history.
What defines a biodiversity hotspot?
A region with high numbers of endemic species that is significantly threatened by human activity.
