General Ecology Exam 3- UWSP

Ecological community

an assembly of a population of two or more species occupying the same geographical area at a particular point in time

Competition fitness effects

-/-

Exploitation (predation, herbivory, parasitism) fitness effects

+/-

Mutualism fitness effects

+/+

Commensalism fitness effects

+/0

Amensalism fitness effects

-/0

Neutralism fitness effects

0/0

Why did the equation dN/dt = rN((K-N)/K) not work?

That was for intraspecific competition, not interspecific

α

competition coefficients

α12 is

the effect of an individual of species 2 on the population growth of species 1

α21 is

the effect of an individual of species 1 on the population growth of species 2

What did the logistic growth equation add to include interspecific?

-α12N2

why do we use isoclines of zero population growth to make predictions about the long-term outcome

coexistence is more likely when the magnitude of interspecific competition is relatively low

Which species wins?

Species 1 wins
Stable equilibrium at K1

Which species wins?

Species 2 wins
Stable equilibrium at K2

Which species wins?

Winner varies
Stable equilibrium at either K1 or K2 depending on starting conditions

Which species wins?

both, stable equilibrium

Predation

broadly refers to the consumption of one organism (prey) by another organism (predator)

Lotka-Volterra predator-prey equations mimic

the predator-prey patterns we see in nature and can be used to explore predator-prey cycles

Lotka-Volterra predator-prey equations refer to the prey as

Hosts

Lotka-Volterra predator-prey equations refer to the predators as

Parasites

Why are predators described as parasites and prey as hosts?

the equation was initially developed in the context of parasite-host interactions

prey population is limited by

predation

predator population is limited by

prey abundance

consumption rate of prey

pNhNp

Lotka-Volterra prey equation

dNh/dt = rhNh - pNhNp

in Lotka-Volterra prey equation what is rh

host per capita rate of increase

in Lotka-Volterra prey equation what is Nh

Number of hosts

in Lotka-Volterra prey equation what is pNh

predation rate

in Lotka-Volterra prey equation what is Np

number of predators

predator birth rate equation

cpNhNp

what is c in predator equation

host to predator conversion rate

what is dp in predator equation

the mortality rate of predators

Lotka-Volterra predator equation

dNp/dt = cpNhNp - dpNp

Mutualism

any interaction from which all participants gain a
fitness benefit

facultative mutualisms

species that can live without their mutualistic partners

obligate mutualisms

mutualistic relationships that are obligatory (one or both can’t live without the other)

Symbiosis

some interactions are super tight knit

Swollen thorn acacia

Native to new world

What are swollen thorn acacia traits

enlarged thorns with a soft, easily-excavated pith, enlarged foliar nectaries, and Beltian bodies

what are Beltian bodies

leaflet tips that are modified into concentrated food sources (lipid proteins and carbs)

Whistling thorn acacia

Africa

What are elaisomes

small structures attached to a seed

why are elaisomes important to whistling thron acacia

the ants will take the elaisome and drag it into their grave yard and eat the elaisome, then the seed will grow in nutrient dense area

Myrmecochory

seed dispersal by ants

Why do ants in swollen thorn acacia avoid the flowers

the flowers produce a chemical repellent, which repels the ants from the inflorescences but is apparently not noticed by pollinating bees

Why would David Moeller (2004) argue that facilitation can reduce the effects of competition among sympatric Clarkia spp

Facilitation can ameliorate the effects of things like competition (heterospecific Clarkia spp. compete for similar resources but also help each other indirectly by attracting pollinators to the region in which they occur)

pollen limitation

many angiosperm do not use the amount it should use

What does commensalism mean

interspecific interactions where one species benefit and the other species is not effected

examples of commensalism

Large ungulates (such as cattle) and birds (such as cattle egrets), where the movement of ungulates stirs up insects, upon which the birds feed

What does amensalism mean

interspecific interactions where one species is harmed and the other species is not affected

examples of amensalisms

Ungulates trampling grass

What does neutralism mean

What is species diversity and how do we quantify it?

diversity index

Most diversity indices are functions of both

species richness and species evenness

Robert Whittaker on abundance

few plant species have low coverage, most plant species have moderate coverage, few plant species have very high coverage

Frank Preston on abundance

Few bird species are rare, most bird species are moderately abundant, few bird species are abundant

what did Deborah Rabinowitz mean when she discussed what she called the seven forms of rarity

organisms only have Small geographic ranges, Narrow habitat/resource
specificity, or small populations

primary productivity

the synthesis of organic compounds from atmospheric or aqueous carbon dioxide via photosynthesis

primary productivity is quantified by

measuring changes in biomass

Robert MacArthor found that

plant communities with greater foliage height diversity supported more diverse bird communities

Equilibrium theory of island biography

theoretical construct first published in the 1960’s by Robert MacArthur and E.O. Wilson, that seeks to explain and/or predict levels of diversity on islands

large and near islands will support ___ amount of species

most

latitudinal gradient in species diversity

observation that species diversity is highest near the equator and declines with increasing latitude

Red Queen Hypothesis (Leigh Van Valen)

Proposes that species must constantly evolve in order to survive while pitted against ever-evolving and opposing organisms in a constantly changing environment

how did J.H. Brown argue that red queen hypothesis might be related to higher species diversity in the tropics

the species needed to sprint to just keep up with the changes and were never getting ahead

What are the six processes JH brown describes

Time since perturbation
Productivity
Environmental heterogeneity
Favorableness
Niche breadth and interspecific interactions
Differences in speciation and extinction rates