ch 7 species interactions key concepts

Differentiate between density independent and density dependent factors affecting growth rates

Density independent - disturbance, environmental conditions
Density dependent - food, space, water (intraspecific competition) with interspecific interactions

Differentiate between intraspecific and interspecific competition and give examples

Intraspecific - competing with same species as own
Interspecific - competing with different species in same area

Distinguish interference competition from exploitation competition

Interference - direct aggressive behavior between organisms that interfere with foraging, survival, reproduction, or habitat establishment (I stop you from getting it)

Exploitation - indirect aggressive behavior between organisms through a common limiting resource (I get it before you can)

Define and give examples of character displacement and competitive release

Character displacement - minimizes competition between species; organisms evolve to become more different to reduce competition (bird beaks, more different to specialize on different seeds)

Competitive release - when species expands its niche after a competitor is removed (chthamalus barnacles spreads to lower zone when balanus is removed)

Explain how we can model co existence

Lotka Volterra Competition model; predicts if both species limit themselves more than limit each other, or if one species always outcompetes the other

Explain how K will change for population 1 if population 2 is around

K1 is the maximum number of individuals of population 1 the environment can support on its own.

If pop 2 is around, the growth of pop 1 is now limited not only by size, but also by competition form pop 2.

Explain the competition coefficient

alpha (a), how much an individual of one species reduces the growth of another species, relative to its own members

Understand the importance of the Lotka-Volterra Model

Models the predator-prey version of how populaitions can cycle. the competition version predicts whether two species can coexist or not

What are the zero growth isocline?

Line on graph that shows all combinations of two species population sizes where growth rate of one species is zero

What are the three outcomes when 2 species are put together?

Species 1 excludes species 2 (look at value K1)
Species 2 excludes species 1 (look at value K2)
Coexistence (favorable depends on vectors)

Define predation, list 5 distinct types, and give examples

Occurs when members one species eat those of another/same species
Herbivory: plant eaters
ex: cows grazing on grass

Carnivory: meat eaters
ex: wolf hunting a deer

Cannibalism: eating one own species
ex: praying mantis females eat males after mating

Parasitoids: insect laying eggs as host to kill it
ex: braconid wasp larvae consuming a caterpillar from the inside

Parasitism: feeding on another organism without killing it
ex: tapeworm in human intestines

Define mutualism, list 2 types, and give examples

Relations between two organisms that benefits both
Obligatory - organisms cannot survive in the absence of the other partner (fungus and cyanobacterium)
Facultative - organism can lead an independent existence (bees and flowers)

Define mutualism, list 2 types, and give examples

Define commensalism, list 3 types, and give examples

Benefits one organism, the other isn’t benefits nor harmed
Inquilism - one organism lives inside the habitat or body of another species, without causing harm (birds nesting in tree holes)
Metabiosis - one organism benefits from the life activities or remains of another organism after death (hermit crabs using empty snail shells)
Phoresy - one organism uses another for transportation, doesnt harm (mites hitching a ride on insects like beetles)

Define ammensalism and give examples

One species is harmed, while the other is unaffected
ex: humans polluting water