Species Interaction Flashcards
tropic interactions
involve feeding
benefit one species at the expense of another (+/-)
predation (predator, prey)
herbivory (plant, animal)
parasitism (parasite, host)
avoidance mechanisms
employed by prey
crypsis (camouflage, mimicry)
non-cryptic defenses (chemical defenses, armor/weaponry, warning signals, mimicry)
behavioral defenses (alarm calls, threat displays, group behavior)
cryptic defenses
involve deception
camouflage: blending into or looking like your background habitat
mimicry: looking like something else
employed by predator and prey
ex: pattern of Eudryas moth looks like bird droppings
non-cryptic defenses
noxious or harmful to the predator in some way
chemical: smelly, distasteful, confusing, toxic
mechanical: spikes, spines, teeth, claws, armor
aposematic signals
- aka presence of aposematism
- bright colors or patterns that warn predators of toxicity
- avoided cost: getting eaten in the first place since there is a signal that prevents it from happening
Batesian mimicry
- some organisms skip the defense and rely on the warning
- rely on the fact that there are others in the community with the same aposematic signal and an actual defense
relies on sensitization - predators begin to associate a visual stimulus with a noxious defense
Mullerian mimicry
- species that look the same (share the same aposematism) and have a defense mechanism to back the signal up
- beneficial to both species since they predators will associate the visual stimulus with both prey
behavioral defenses
warning call: alerts others of your own species to the presence of danger
threat display: makes you look more intimidating to predators
schooling and herding: an individual is less likely to be captured
herbivory defense mechanisms
plants also have avoidance mechanisms
chemical defenses, spines/thick bark
herbivore adaptations
have adaptations to get around plants’ defenses
tolerance of chemicals, tough teeth/mouth, behavioral adaptations
coevolution
many predator and prey relationships evolve together in order to adapt to each other
giraffes grew tougher mouths due to the thorns that evolved due to giraffes
parasites
eat their hosts without killing the hosts
mortality depends on the extent of the infection
endoparasites
live inside the host
macro: different types of worms and flukes
micro: bacteria, viruses, and fungi that we refer to as pathogens
ectoparasites
feed from outside the host
macro: ticks, fleas, mosquiotes
micro: fungi, viruses, bacteria
predator-prey interactions
shape ecosystems
ex: otter predation keeps sea urchin populations under control, which helps to keep the kelp population stable and present
otter-kelp interaction
indirect interaction
the presence of otters increases the presence of the kelp because the otters keep the population of sea urchins in check
diversity/evolution of traits
is a result of trophic interactions
shape phenotypes and ecosystems
competition
-/0 or -/- interaction
competitive exclusion (0/-)
competitive coexistence (-/-)
competition occurs when
species both want to use a limiting resource
takes place over a limiting resource: food, space, light - every resource has a carrying capacity and affects the carrying capacity of other animals
interference competition
actively preventing the other species from accessing a resource by displaying agonistic or territorial behavior
exploitation competition
more efficient user of the resource
tree competition
when competing populations live in the same habitat, both populations are negatively affected
early in succession, tree species that grow fast and need a lot of sun are the most common. As the forest gets thicker, these species lose out to the other tree species that are more tolerant of shade
competitive exclusion
species is prevented from occupying a habitat by its competitor, but the competitor is not affected
0/-
competitive coexistence
each of the coexisting species stays in the habitat but both populations have a lower carrying capacity
resource partitioning
evolutionary pattern that helps potentially competing species avoif competition
takes place when competing species use different parts of a limiting resource
character displacement occurs as phenotypes evolve to fit those niches
ex: Galapagos finches
competitive coexistence
fugitive species
species selectively leaves habitat when a major competitor is present
ex: cheetahs abandon their grounds when lions are near since they know they cannot compete
realized niche
spaces and resources in a habitat that a species actually uses when coexisting with a competitor
often smaller than fundamental niche
fundamental niche
spaces and resources in a habitat that a species would use under ideal circumstances
tested via removal experiments
positive interactions
benefit one or both species
commensalism (0/+)
mutualism (+/+)
commensal interactions
positive for one species and neutral for the other
ex: Pilotfish and sharks
ex: frogs and tree bark
true commensalism
may be rare
barnacles on a whale can benefit by having a good place to live and access to food and water
dense clusters can cause skin irritation and eczema
increase drag on whale
mutualistic interactions
benefit both species
aphids excrete sugary liquid called honeydew that ants find delicious and nutritious - in return, ants protect aphids by biting and spraying formic acid
ants in bullhorn acacia trees
clear the ground around their tree, getting rid of competing plant species
attack other insects that approach or other mammals that eat the leaves
myrmecophytes
specialized structures to provide housing and food for ants
hollow structures with doors provide a shelter for ants to build their nest
Mullerian bodies are protein and sugar-rich and produced by plants to serve as animal foodin
interaction outcomes
vary depending on how stressful the habitat is
Iva and Juncus coexist in coastal habitats, but in some areas the interactio is competitive - they decrease each other’s carrying capacity due to the limited nutrients available in the soil
competition more common in less stressful environments since populations are limited by each other vs. abiotic factors
outcomes in stressful environments
in other areas, the interaction is commensal - the presence of Juncus increases the success of Iva
tends to occur where the soil is extra salty - Juncus thrives well in soil and its presence changes the habitat into a habitat where Iva can thrive
plants do not grow enough to compete with each other
ecological facilitation
stressful environments
high altitude, frequent storms, unstable or poor soil, variable access to food
