All Flashcards
Define Island Biogeography Theory.
Explains how island size and location affect species number, balancing immigration and extinction.
What are endemic species?
Species native to a specific area, often specialists, vulnerable to change.
Define invasive species.
Non-native species that spread rapidly, causing harm, often generalists.
What is adaptive radiation?
Evolution of many species from a single ancestor, each filling a different niche.
Define immigration in IBT.
The arrival of new species to an island.
Define extinction in IBT.
The dying out of species already present on an island.
Define species richness.
The number of different species represented in an ecological community, landscape or region.
What is a generalist species?
A species that can thrive in a wide variety of environmental conditions and make use of a variety of different resources.
What is a specialist species?
A species that can thrive only in a narrow range of environmental conditions or has a limited diet.
Define ecological niche.
The role and position a species has in its environment; how it meets its needs for food and shelter, how it survives, and how it reproduces.
What is the effect of introducing an invasive species?
Displacement of endemics, habitat alteration, and economic costs.
What causes adaptive radiation?
Limited immigration and varied environmental pressures on islands.
How does island size affect species survival?
Larger islands support larger populations, reducing extinction risk.
How does distance from the mainland affect immigration?
Closer islands have higher immigration rates due to easier accessibility.
What are the consequences of habitat alteration by invasive species?
Changes in ecosystem structure and function, impacting native species.
What is the effect of a lack of natural predators on invasive species?
Population explosions and rapid spread of invasive species.
What is the effect of increased competition on extinction rates?
Increased competition leads to higher extinction rates as resources become limited.
How does geographic isolation contribute to speciation?
Geographic isolation prevents gene flow, allowing populations to diverge and form new species.
What are the economic effects of invasive species?
Significant damage to agriculture, forestry, and fisheries, leading to economic losses.
How does the introduction of a generalist species affect an ecosystem?
Generalist species can outcompete specialists, leading to a decrease in biodiversity.
What is the core concept of IBT?
Dynamic equilibrium between immigration and extinction rates determines species richness.
How does island size affect extinction rates?
Larger islands support larger populations, reducing extinction risk.
How does island distance affect immigration rates?
Islands closer to the mainland have higher immigration rates.
Why are endemic species vulnerable?
They are often specialists with narrow niches, sensitive to change.
Why are invasive species successful?
Lack of predators, generalist nature, and rapid reproduction.
What is the impact of invasives on endemics?
Invasives outcompete endemics, potentially driving them to extinction.
Describe the relationship between island size and species richness.
Larger islands tend to have more species due to greater habitat diversity and resources.
Describe the relationship between island distance and species richness.
Islands closer to the mainland tend to have more species due to higher immigration rates.
What are the key factors that influence the equilibrium number of species on an island?
Island size, distance from the mainland, immigration rates, and extinction rates.
What are the main characteristics of invasive species?
Broad ecological niche, ability to thrive in various conditions, lack of natural predators, and rapid reproduction rates.