Island Ecosystems Flashcards
What are the two criteria that defines an island?
- Sub-continental land
* Surrounded by water
A peninsula is an island. T or F?
False
It is a strip of land that still links to a land mass in some way
Are continents islands?
No.
What is a group of islands called?
An archipelago
What is the biggest island in the world?
Greenland
What are the 3 main types of island?
- Continental island
- Continental fragment
- Oceanic Island - hot spots and island arcs
What are the two types of oceanic island?
- island arcs
* hot spots
What is a continental island?
Part of a continental lane mass but has water that surrounds it because the land mass is lower in some areas.
E.g. GB and Ireland are actually attached to Europe!
What’s a continental fragment?
Fragments of the continent which have broken off due to geological processes
E.g NZ
What are oceanic islands, what are the two types and what are these?
Oceanic islands are islands that have never been connected to a continent.
A hot spot is a hot spot of volcanic activity which causes weaknesses in the cracks which forms volcanic islands.
An island arc are long chains of volcanoes found along tectonic plate boundaries.
Is species richness good or bad on islands and why?
Bad because not many species would have been there when it was formed and not many would have made it there
Why are island generally cooler, wetter and less seasonal than mainland?
More influenced by the sea around them
The ocean around islands provides ______ stability. E.g?
Climatic stability
E.g rain formations hitting mountains
What is sweep stakes dispersal?
When individuals arrive on an island
Sweepstake dispersal is _____ toward taxa because..
Biased towards taxa because birds can travel more easily than most mammals for example.
What is it called when individuals arrive on an island via floating land mass or by flying?
Sweepstake dispersal
What is reproductive isolation and what is the consequence of having a reproductively isolated species on an island?
Reproductive isolation is when individuals are no longer related to their original population on mainland. Occurs via geological processes or sweepstake dispersal to an island.
The consequence is that they become a subset of the population and are unable to reproduce with mainland population
What is in-situ speciation?
Rapidly advancing evolutionary soeciation
What is adaptive radiation?
When species that arrive on an island go through the taxon cycle.
What is the taxon cycle?
When species become generalists because they take on a lot of resources and then because of competition they specialise in individual niches
E.g finches on Galápagos Islands
What does the species area relationship assume?
The bigger the Island the more species
equation: S=cAz
What is the equilibrium model?
No. Of species on an island is at equilibrium point depending on size of island, how isolated it is, how easy to become extinct and how easy it is for individuals to colonise
Island communities tend to be a ______ of main land communities
Subset
What is disharmony?
When there are key missing aspects of an ecosystem
What is ecological release?
When disharmony causes species to change their ecological restraints and requirements due to a change in ecosystem
Competition is greater or lesser when species have become successful generalists?
Greater
What is a generalist species?
A species able to eat a variety of foods and adapt their behaviour and physiology to survive in different ecosystems and habitats
Generalists become successful through adaptive ____ and the ____ cycle. This results in more or less competition?
Adaptive radiation
Taxon cycle
More competition
What is a keystone species?
An organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether. (National geographic website)
What is edemism?
A species that only exist in a defined geographic area
What are exotic species?
Ones that have been introduced
What is nanism?
Smaller species
What is giantism?
Larger species
Explain a couple of consequences of flightlessness
- increases isolation
* fitness benefit removed
What are super generalists?
Species able to adapt to new and broad ecological environments because there are less constraints over which resources they can take advantage of
What is K-selection?
A slow growing species that has a reduction in the abundance of offspring production and an increased parental investment
What is a R-Species?
Fast colonisers that are fast reproducers with little parental investment
What two things makes islands especially vulnerable?
- Endemic species
* evolutionary distinct species
How can we conserve islands? Name a couple
- reduction or eradication of exotic species
- in-situ and ex-situ breeding programmes
- reductions in habitat loss and exploitation
