Stability Flashcards
Paul Erdos random network demonstrated that as the number of species in a community increases the proportional number of links between species required to cover all species (increases or decreases)
Decreases because as the number of species increases the number of links to connect the species decreases
Place these in early or late succession
Generalist, larger, smaller, comp inferior, comp superior, r selected, specialist, colonizer, k selected
Early: smaller, comp inferior, generalist, r , colonizer
Late: larger, comp superior, specialist, k
What succession is retreating glacier and what is fire
Primary
Secondary
Ecological systems are examples of small world networks
A network in which most nodes are not neighbours of one another, but most nodes can be reached from every other node by a small number of other links
What is meant by weak and strong links
Weak: a link that does not have strong interaction with the other nodes (interaction is more sporadic or less significant)
Strong: are those that link individuals that interact often and whose interactions is significant
Weak links often are responsible for providing resiliency to ecological systems
Because they connect the strong hubs to the other ones which connects the whole ecological system together
They provide access to parts of the network not available via strong links
Erdos random network is analogous to who’s model of random links in ecological communities
Robert mays experiments constituting artificial communities using random links between individuals individual species
Differentiate between dominant and keystone species
Keystone: important to community function is disproportionate to their biomass
Dominate: importance is proportional to its biomass (numerous or large)
Match theory to person
I) increasing species diversity increases stability
II) increasing species diversity decreases stability
III) interaction strengths are critical in the stability- diversity relationship
I) MacArthur
II) May
III) Yodzis
Assumptions of Adaptation
Adaption has a genetic basis and therefore can be changed by natural selection
Fitness is correlated to adaptation
What effects diversity on large scale and small scale
Large: physical (habitat variables)
Small: biotic factors (species to species interactions)
Why did bullfrog pop increase in places with bluegill sunfish
Because dragonfly’s control bullfrog pop as predators, but the bluegill prefer the dragonflies over the bullfrog. This causes less predation to the bullfrog and population increases
Six degrees of separation
That for any two people in the US there is an average of 6 steps of interaction to get to this other person
Small world
Taking both random and regular and making something better
Create a regular network and then make a small portion random. This makes the system both robust and efficient
Why are keystone species so important
Because through their actions weak links are maintained in a community
Links upon which stability and function depend
