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Define Island Biogeography Theory.
Explains how island size and distance from the mainland affect species richness, balancing immigration and extinction.
Define Immigration (in IBT).
The arrival of new species on an island.
Define Extinction (in IBT).
The dying out of species already present on an island.
Define Endemic Species.
Species native to a specific area, often specialists.
Define Invasive Species.
Non-native species that spread rapidly and cause harm, often generalists.
Define Adaptive Radiation.
The evolution of many new species from a single ancestor, each filling a different niche.
Define Species Richness.
The number of different species represented in an ecological community, landscape or region.
Define Generalist Species.
Species that can thrive in a wide variety of environmental conditions and make use of a variety of different resources.
Define Specialist Species.
Species that 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, economic costs.
What causes adaptive radiation?
Limited immigration, natural selection, geographic isolation.
How does habitat loss affect endemic species?
Increases their risk of extinction due to limited suitable habitat.
What are the effects of invasive species on ecosystem equilibrium?
Disrupts equilibrium by outcompeting native species, altering habitats, and causing economic damage.
How does geographic isolation drive evolution?
It allows populations to evolve independently, leading to unique adaptations and speciation.
How does increased competition affect extinction rates?
Increased competition leads to higher extinction rates as species struggle for resources.
How does the lack of natural predators affect invasive species?
Allows their populations to explode, leading to rapid spread and displacement of native species.
What is the effect of habitat alteration by invasive species?
Changes the structure and function of ecosystems, impacting native species and ecosystem services.
How does climate change affect endemic species?
Increases their vulnerability due to their narrow ecological niches and sensitivity to environmental changes.
How does natural selection affect species on islands?
Different environmental pressures lead to different adaptations, driving species divergence and adaptive radiation.
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.