Lecture 13: Communities: Competition & coexistence Flashcards
define parasitiods
“internal predators” that must kill their
host to complete their lifecycle
define parasites
typically much smaller than their hosts and do not kill the host as part of their lifecycle (they “graze” the tissues of the host)
define ectoparasites
parasites that live on the outside of a living host
define endoparasites
parasites that live on the inside of their living host
define transmission mode
- how a parasite finds its host
- can be highly variable, and alters
the complexity of interactions
parasite transmission - horizontal transmission
- movement of the parasite between individuals that are not parent and offspring
- can occur between members of the same or
different species - close physical contact is needed
parasite transmission - Vertical transmission
movement of the parasite between host
parent and offspring.
parasite transmission - vector
an organism that facilitates horizontal transmission, typically without suffering severe symptoms
parasite transmission - Reservoir species
Species that can be infected with the parasite without any or severe symptoms, allowing the parasite to persist in a community outside of its primary host
Pathogen
A microbial parasite that causes disease in its host
how can the Lyme disease bacterial parasite be considered a pathogen
it causes some of its hosts to have a disease
what is a stable product of antagonistic pathogen-host coevolution
Selection tending to produce low pathogen virulence and high host resistance
Rabbits introduced into Australia exploded to a population size of _____
hundreds of millions
Myxoma virus had______ — an ______ between pathogen and host
- mild effects in its natural host
- evolutionary stable state in the arms race
define Kleptoparasitism
Direct theft of prey or other resources, resulting in a negative impact for the host
broad definition of parasitic interactions
involves the consumption of host resources, resulting in a negative impact on the host.
define Brood parasitism
Infiltration of host nests by the offspring of another species, exploiting parental care and resulting in a negative impact on the host and their offspring
define mutualism
Reciprocal adaptations in two or more species that benefit all species.
define symbiosis
- Any interaction where members of different species live in intimately connected interactions
- outcome of interaction can be highly variable.
Mutualisms are an ______ between species
evolutionary collaboration
what can mutualism often form between
consumer and resource species when both species offer services outside of consumer resource interaction and evolutionarily shift into a new category of species interaction
how may mutualisms be actively maintained
selection exerted by third party resource species or consumer species
define trophic mutualisms
Partners have complementary functions for obtaining energy and nutrients
The_______ between leaf-cutting ants and fungus is _______
- trophic mutualism
- attacked by parasitic fungus
Mutualism with ______ has also evolved to defend mutualistic fungus against the parasitic fungus invader - ______
- defensive bacteria
- defensive mutualism
what are Defensive mutualisms
- Plant-ant mutualisms are one of the best studied defensive mutualisms.
- Plants provide shelter and/or food to attract resident ants, and ants defend the plants against herbivore enemies
define dispersive mutualisms
- Plants get reproductive services, animals get food
- example: Pollination and seed dispersal
What type of interaction exists between coral and reef fish?
- commensalism
- reef fish gets benefits from coral
- coral does not care about it and has no interaction with the fish
- coral – ecosystem engineer
define Ecosystem engineer
An organism that causes state changes in the environment that subsequently serve as vital resources for other organisms
The persistence of the _______ created by an ecosystem engineer seem to be critical in determining the level of influence this interaction has on a community
state changes
ecosystem engineering - chemical
microbes and plants create chemical gradients
ecosystem engineering - Bioturbulance
burrowing and digging organisms cause turnover of nutrients and create disturbed habitat types
ecosystem engineer - light
organisms that alter light penetration and scatter
ecosystem engineer - structural
alter the physical environment with structures that create habitat and resources
define competition
- Use or defense of a resource that results in reduced availability of that resource for another organism
- a consumer-resource interaction with -/- consequences
Indirect/exploitation competition
Competition without direct contact between consumers
Direct/interference competition
Competition with direct contact between consumers in access to the resource
