metapopulations, competition, parasitism and disease Flashcards
metapopulation
a population of populations
rescue effect
high rates of immigration may save subpopulations from extinction
how do you increase metapopulation persistence?
increase patch size
increase patch connectivity
competition
the conflict between two species for some resource
mutualism
++
parasitism
+-
competition
–
commensalism
0,+
amensualism
0,-
intraspecific competition
comp between individuals of the same species
interspecific competition
comp between individuals of different species
exploitation
two species consume a shared, limiting resource; species that requires less of the resources “wins”
interference
two species interact antagonistically for access to a resource
allelopathy
occurs when a plant releases chemicals toxic to competitors in the soil
co-existence
two species use the same resources in different ways
exclusion
two species use the same resource in the same way; one becomes extinct
competition exclusion principle
if two species use a resource in exactly the same way, one will eventually drive the other to extinction
ex) paramecium; putting the two paramecium together that both eating floating bacteria will cause one of the species to go extinct. Putting two paramecium together with one that eats floating bacteria and the other that eats yeast allows coexistence
resource partitioning
co-existing species use the same resources in different ways
ex) anoles live in the same place and eat similar food, but can coexist because each species lives in a different part of the tree
predation
one organism kills and eats another individual
herbivory
one organism eats living tissue of plants/algae
parasitism
one organism lives on or in another individual, feeding on parts of the host
ways to avoid predation
running away
blending in (camouflage, octopuses)
standing out (bright colors, poison dart frogs)
mimicry (moth mimics stinging wasp, other frogs mimic poison dart frogs)
playing dead (hognose snake)
fighting back
signaling to predator (deer with white butt)
aposematism
appearance of prey that indicates to a predator that it is dangerous or unpleasant
Müllerian mimicry
two unpalatable species have similar appearance, all are toxic
Batesian
a palatable species mimics an unpalatable species
ways plants reduce herbivory
avoidance
tolerance
defenses
compensation
tolerance of herbivory
removal of plant tissue stimulates growth
plant secondary compounds
diverse chemicals used by plants to reduce herbivory
constitutive secondary compound release
compound is always produced
induced secondary compound release
compound only produced in response to herbivory
keystone species
species that if removed, will cause the next “dominant” species to drive all other species in environment to extinction
ex) sea stars
VOC
volatile organic compounds
pathogen
parasites that cause disease
Ectoparasites
outside;
plants: mistletoe, orange rust
animals: fleas, ticks
endoparasites
inside
bacteria or worms
vertical parasite transmission
between offspring and parent
ex) HIV, herpes
horizontal parasite transmission
between other individuals
ex) malaria
dI/dt=βSI-mI
model of disease dynamics
I
density of infected individuals
S
density of susceptible (uninfected) individuals
β (disease dynamics)
transmission coefficient
m (disease dynamics)
combined death and recovery rate
(births and deaths)
SI
rate of encounter between susceptible and infected individuals
BSI
disease transmission
mI
rate at which infected individuals recover
disease can increase and spread when
βSI-mI>0 or ST>mβ
coevolution
evolution of two interacting species, which respond to selection imposed by other species
