Ecology: Ecosystems and Communities

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Questions and Answers

Considering scenarios where a keystone species is removed from an ecosystem, which of the following is the MOST likely long-term consequence, assuming no other interventions occur?

A significant increase in overall species diversity due to reduced competition.
A trophic cascade leading to a simplified food web and potential loss of biodiversity. (correct)
Enhanced stability of the ecosystem as other species adapt and fill the vacant niche.
A shift towards a new equilibrium state with a different dominant species but similar ecosystem functions.

In the context of nutrient cycling within an ecosystem, how does deforestation MOST directly impact the phosphorus cycle, considering the long-term implications for soil fertility and plant growth?

It accelerates the rate of phosphorus absorption by the remaining plant life due to increased sunlight exposure.
It increases phosphorus runoff and erosion, depleting soil phosphorus reserves. (correct)
It disrupts the weathering process of rocks, leading to a rapid increase in available phosphorus in the soil.
It increases phosphorus retention in the soil by reducing erosion and runoff.

How might an increase in ocean acidity due to rising atmospheric carbon dioxide levels MOST profoundly affect coral reef ecosystems, considering the intricate symbiotic relationships and structural integrity of the reefs?

Weakened coral skeletons and reduced reef building, impairing habitat provision for diverse marine species. (correct)
Increased coral growth rates due to enhanced carbon availability for photosynthesis by symbiotic algae.
Enhanced resilience of coral reefs due to increased tolerance of corals to thermal stress.
A shift in coral species composition towards more acid-tolerant species, maintaining overall reef biodiversity.

Considering the principles of restoration ecology, which approach would be MOST effective in restoring a severely degraded wetland ecosystem that has experienced significant topsoil loss and invasive species infestation?

A phased approach that includes soil stabilization, removal of invasive species, and reintroduction of a diverse array of native plant and animal species, along with continuous monitoring. (A) Signup and view all the answers

How does habitat fragmentation MOST significantly impact the genetic diversity of a population of a specialized, non-mobile species, such as a rare orchid, within a fragmented forest ecosystem?

Reduced gene flow between subpopulations, potentially leading to inbreeding depression and loss of genetic diversity. (C) Signup and view all the answers

In the context of population ecology, how does the Allee effect MOST likely influence the population dynamics of a species with cooperative breeding behavior when the population size falls below a critical threshold?

It results in decreased per capita birth rates due to reduced cooperative interactions and increased predation risk. (D) Signup and view all the answers

Considering the different types of species interactions, in which scenario would a commensalistic relationship MOST likely evolve into a mutualistic one over time?

When the host species begins to receive a benefit from the presence of the commensal species due to environmental changes. (D) Signup and view all the answers

Suppose a scientist discovers a new species of plant in a temperate deciduous forest. This plant exhibits rapid growth, high seed production, and the ability to thrive in disturbed areas. What is the MOST likely long-term ecological consequence of introducing this plant into a stable, undisturbed area of the same forest?

A decrease in the abundance of native plant species due to competitive exclusion. (C) Signup and view all the answers

Given the complexities of the carbon cycle, what is the MOST significant long-term impact of large-scale deforestation on the global climate, considering both biotic and abiotic factors?

An increase in atmospheric carbon dioxide levels due to reduced carbon sequestration and increased decomposition of organic matter. (C) Signup and view all the answers

Considering the principles of thermodynamics and energy flow in ecosystems, why is the transfer of energy between trophic levels typically inefficient, with only a small percentage of energy being converted into biomass at the next level?

Energy is primarily lost as heat due to metabolic processes, and some energy is not consumed or assimilated. (B) Signup and view all the answers

Flashcards

What is ecology?

The study of relationships between living organisms and their environment.

What are abiotic factors?

Non-living components of the environment influencing organisms.