Biodiversity Flashcards
Who was Alexander von Humboldt?
(1769-1859) A geographer, meteorologist and historian. He was an explorer.
What was one of Alexander von Humboldt’s greatest discovery?
Mapping out the climatic zones of the earth using isothermal lines.
What is the latitudinal diversity gradient?
The idea that the nearer you approach the tropics, the greater the increase in variety of structure, grace of form and mixture of colours.
What is the altitudinal gradient?
There are more species at low and mid-altitude and fewer at higher altitudes.
What is the depth gradient?
As you get further down into the ocean, there are fewer and fewer species.
What are the different ways in which diversity can be measured?
Local (alpha) diversity, turnover diversity (beta), regional diversity (gamma), evenness, functional diversity and sampling.
What does the idea of diversity cover?
The total species for a limited area, the abundance of species in a habitat, the difference of the habitat from others, the sum of everything in a region.
What is alpha diversity?
The number of species found in a given habitat.
What is beta diversity?
How distinct the fauna/flora is from other floras/faunas or turnover - how quickly do species turn over from one locality to another.
What is the Jaccard similarity index?
An index used to calculate beta diversity.
What is high tropical diversity a function of?
High alpha diversity and high beta diversity.
What is gamma diversity?
Regional diversity.
What is functional diversity?
Diversity of species based on their functions - size and locomotion.
What is the intermediate disturbance hypothesis?
The idea that too much disturbance prevents species from becoming established. Too little disturbances mean a few species are able to crowd everyone else out.
What is a goldilocks level of disturbance?
Where disturbance is low enough to let many species get established, but high enough that dominants get killed off frequently, preventing them from taking over.
What is the mid domain effect?
The idea that if there is a lot of species with varying latitudinal ranges randomly arranged, the widely-distributed organisms wil include the tropics - wide-ranging things overlap in the middle.
What is the species-area effects?
The idea that there is more land in the tropics.
What is the problem with the species-area effects?
The biggest land mass is mostly temperate, and if species diversity was driven by area, Russia and Siberia would have a lot of species.
What is the problem with the intermediate disturbance hypothesis?
There is no evidence that disturbance levels are that different in the tropical rainforests compared to other habitats.
What is the problem with the mid-domain effect?
It assumes the tropics have organisms with large ranges, but this is not true - lots of organisms have small ranges.
