Lec 6 Flashcards
Involves direct interaction between individuals
Interference Competition
Is a condition where there is a limited supply of resources
Resource Limitation
Takes place when members of the same species compete
Intraspecific Competition
Happens between individuals of two species that reduces the fitness of both
Interspecific Competition
Competition involving the use of limited resources is called
Exploitative Competition or Resource Competition
Tilman and Cowan (1989)
Intraspecific Competition Among Plants
As the stand of trees develops, more and more biomass is composed of fewer and fewer individuals, a process called
Self-thinning
Denno and Roderick (1992)
Intraspecific Competition In Animals
Grosholz (1992)
Interference Competition Among Terrestrial Isopods
G.F. Gause (1934)
Competitive Exclusion and Niches
States that two species with identical niches cannot coexist indefinitely
Competitive Exclusion Principle
Linked differences in beak size and form among Darwin’s finches to differences in their feeding niches
David Lack (1947)
Represented the feeding niches of Darwin’s finches by their beak morphology
Peter Grant (1986)
Large ground finch, eats larger seeds
Geospiza magnirostris
Medium ground finch, eats medium-sized seeds
Geospiza fortis
Small ground finch, eats small seeds
Geospiza fuliginosa
Niche overlap and competition between barnacles
The barnacle Balanus balanoides, located in the middle and lower Intertidal zones. While the Chthamalus stellatus, located in the upper Intertidal zone.
Indicate that the Balanus is limited to the middle and lower intertidal zones because it cannot withstand the longer exposure to air in the upper intertidal zone.
Joseph Connell (1961)
Is the circumstances in which two species differ more from each other in geographic areas where they occur together than where their distributions do not overlap
Character Displacement
Mark Taper and Ted Case (1992) six criteria for character displacement
- Morphological differences
- Genetic basis
- Different founder populations
- Known effect
- Demonstrated competition
- Differences in the resources available
Enhances the fitness of one individual while reducing the fitness of the exploited individual
Exploitative Interaction
Consume live plant material but do not usually kill plants
Herbivores
Kill and consume other organisms
Predators
Live on the tissues of their host, often reducing the fitness of the host, but do not generally killing it
Parasites
An insect whose larva consumes it’s host and kills it in the process
Parasitoid
Induce disease, a debilitating condition, in their host
Pathogens
Is when one organism makes its living at the expense of another
Exploitation
Also known as the spiny-headed worms, that change the behavior of amphipods, small aquatic crustaceans
Acanthocephalans
Uninfected amphipods avoid the light
Negative phototaxis
Infected amphipods swim toward light
Positive phototaxis
Bethel and Holmes (1977)
Positive phototaxis
A life stage of Acanthocephalan where it starts to infect it’s host
Cystacanth
A process where plants grow tall quickly
Bolting
Flower-like leaves
Pseudoflower
Thomas park (1948)
Predation, parasitism, and competition in populations of Tribolium
Flour bettle
Tribolium confusum
Body cavity of bettle
Haemocoel
Studied the influence of a herbivorous stream insect on the algal and bacterial populations upon which it feeds
Gary Lamberti and Vincent Resh (1983)
They make up about 25% of the total biomass of benthic animals
Helicopsyche
Mites that infesting red foxes in the North-central Sweden
Sarcoptes scabiei
Proposed that cycles of abundance on snowshoe hare and lynx populations are driven by variation in amount of solar radiation as a consequence of sunspot cycles
Charles Elton (1924)
Are situations in which members of an exploited population have some protection from predators and parasites
Refuges
Variety of Refuges
Flight for birds. Large size for some animals like elephant
Many forms of spatial refuge
- Burrows
- Trees
- Air
- Water
- Land
Living in a large group provides a type of refuge
Protection in Numbers
Results in increasing rate of food intake as prey density increases
Predator functional response
Results in increased predator density as prey density increases
Numerical response
Functional response and numerical response are put together
Combined response
Takes place when prey can endure their individual probability of being eaten by occurring at very high densities
Predator satiation
The result of prey avoiding high-risk situations
The ecology of fear
Proposed an alternative approach which focused on the functional response of predators
Roger Arditi
States that functional response is determined only by the abundance of the prey
Prey-dependent functional response
Are interactions between individuals of different species that benefit both partners
Mutualism
An interaction between two species benefits one of them, while the other is neither benefited nor harmed
Commensalism
Relationships of some species can live without their mutualistic partners
Facultative mutualism
Relationships where other species are so dependent upon the mutualistic relationship that they cannot live in it absence
Obligate mutualism
Examples of plant mutualism
- Nitrogen fixation
- Nutrient absorption
- Pollination
- Seed dispersal
Was the first to correctly recognize that mycchorhizae involve a mutualistic relation between plants and fungi
Albert B. Frank
Two common types of mychorrhizae
- Arbuscular mychorrhizal fungi (AMF)
- Ectomycorrhizae (ECM)
Mychorrhizae and the water balance of plants
Kay Hardie (1985)
Leaflet tips modified into concentrated food sources called
Beltian bodies
Reef-building corals and unicellular algae
Zooxanthellae
Is growth in which all cell constituents, such as nitrogen, carbon, and DNA, increased at the same rate
Balanced growth
Producing fixed carbon at a much higher rate than other cell constituents
Unbalanced growth
Three kinds of individuals
- Successful mutualists
- Unsuccessful mutualists
- Nonmutualists
Give and receive measurable benefits to another organism
Successful mutualists
Give benefits to another organism but, for some reason, do not receive any benefit in return
Unsuccessful mutualists
Neither giving nor receiving benefit from a mutualistic partner
Nonmutualists
The fitness of plant that produces extrafloral nectaries and that successfully attracts ants effective at guarding it
Successful
The fitness of a plant that produces extrafloral nectaries but that has not attracted enough ants to mount a successful defense
Unsuccessful
The fitness of individuals of a plant such as Helianthella that does not produce extrafloral nectaries
Nonmutualistic
Three variables decrease as distance to the nest decreases
Sign of honeyguide when near to the nest
- The time the bird stays out of sight during it’s first disappearance following the initial encounter
- The distance between stops makes by the bird on the way to the bees’ nest
- The height of the perch on the way to the nest
