Ecology exam 2

What are the two “schools” of population regulation?

1. Density-independent (non-equilibrium)

2. Density-dependent (equilibrium)

Who are the scientists responsible for creating the density-independent

1. H. Andreworth (or Andrewartha)

2. L. Birch

3. T.C.R. White

What does the density-independent school state?

Most mortality factors against a population has little to do with population size or density, instead it’s caused by stochastic abiotic (often with other events) like a flood, fire, freeze, etc.

What school does this graph represent?

Density-independent school

Which scientists were responsible for creating the density-dependent school?

1. J.C. Hotkeg

2. R. Pearl

3. A. Nickelson (or Nicholson)

4. V. Bailey

What does the density-dependent school state?

Populations fluctuate around an equilibrium value and if the population get too big/small biotic factors, such as competition, spread disease, etc. kick in or lax, then the population goes back to equilibrium

What school does this graph represent?

density-dependent school

What is currently believed about both schools of population regulation?

Every population, at some point or another, goes through both schools depending on where they are growth wise.

What school does this graph represent?

Both density dependent and independent schools

Who purposed the group selection theory?

V.C. Wynne-Edwards

What does group selection theory purpose?

1. The unit of evolution and selection is population instead of individual

2. Individuals consciously adjusted birth or consumption rates for the good of the group

Who did Wynne-Edwards base the idea of group selection off of?

D. Lack’s work with songbirds

What is the first problem with group selection theory?

The “cheater” allele once it enters the population via mutation or gene flow will rapidly spread and the population will become non-cooperative

What is the second problem with group selection theory?

for group selection to have major influence in evolution, groups would have to go extinct as fast or faster than individual, which is not possible

What is the third problem with group selection theory?

Requires that population or species can accurately asses available resources and adjust birth or consumption rates for good of the group

What is the fourth problem with group selection theory?

murder or infanticide

What is the first problem of Darwinian evolution?

Altruism

Define altruism

acts committed by an individual (altruist) that decrease his/her chance to reproduction or survive, while increasing those of another individual (beneficiary)

What is the second problem of Darwinian evolution?

The repeated independent evolution of sterile female based worker societies

What order of insects is an example of sterile female based worker societies?

Hymenoptera

Define Hymenoptera

Membranous winged insects that raise someone else’s offspring

• bees

• wasps

• ants

Define @n@l trophallaxis

The exchange of alimentary canal fluids from the anus of one insect to the mouth of another

Define oral trophallaxis

The mouth-to-mouth transfer of liquid food and body fluids between social insects

What is the third problem of Darwinian evolution?

Sexual reproduction

What scientist discovered the coefficient of relatedness (AKA r)?

W.D. Hamilton

Define the coefficient of relatedness ( r )?

The probability that two individuals share a common allele or their genetic relatedness

Why is altruism not a problem for Darwinian evolution?

Most altruism occurs between genetically-related individuals, so it makes sense to protect relatives who share your genes

Who is the scientist who came up with kin selection?

J.M. Smith

What does kin selection purpose?

An alternate explanation for altruism; Darwinian evolution will favor an individual to sacrifice themselves if it involves enough of your relatives

What scientist formalized kin selection mathematically?

W.D. Hamilton

What does Hamilton’s rule/law state?

If C/B < r then selection will favor the act (sacrifice)

What does “C” represent in Hamilton’s law?

Cost of the act

What does “B” represent in Hamilton’s law?

Benefit of the act

What is an alternate equation for Hamilton’s law?

C < Br

What is kin selection based off of?

Inclusive fitness

Define inclusive fitness

Your total genetic contribution of both your own offspring (direct fitness) plus that of all your relatives (indirect fitness)

Which scientist came up with inclusive fitness?

J.B.S. Haldane

Who solved why Hymenoptera evolved to create sterile female-worker based societies?

W.D. Hamilton

If an Hymenoptera egg is fertilized, what will be its gender? is it haploid or diploid?

1. female

2. 2N

If an Hymenoptera egg is unfertilized, what will be its gender? Is it haploid or diploid?

1. Male

2. 1N

Define haplodiploid (haplodiploidy)

A sex-determination system where males develop from unfertilized eggs and are haploid, while females develop from fertilized eggs and are diploid

What does being haplodiploid effect in Hymenoptera?

1. R

2. Inclusive fitness

Why do females in Hymenoptera raise their sisters instead of their own offspring and brothers?

It is less of a genetic waste

Define spermatheca

Sperm storage structure in insects

Why is analyzing the ebb and flow of populations important?

It can help tell us more about the future of a ecosystem or species

What are four sampling techniques?

1. Live traps

2. Percent cover

3. Call frequency

4. Mark-recapture

What are live traps? What species are they useful in capturing?

1. Sherman traps, mist nets, etc.

2. Cryptic and mobile species

How is percent cover useful?

Useful for species that are sessile and are a spreading growth form

Why is call frequency useful when capturing a species?

Useful for species that are cryptic/nocturnal and have a unique call

Define demography

study of members and age structures of a population or species

What was demography originally created for?

Insurance rates

What is demography summarized in?

Life tables

What is a age-specific (cohort) life table?

Follows a group of individuals from birth to death to determine a population age structure; is good for species with a short lifespan

Define cohort

A group of individuals

What is a time-specific (static) life table?

Takes a snapshot of the population age structure at some point in time; good for long-lived species

Define the life table term “x”

Age class; represents some time unit

Define the life table term “N_x”

The number of individuals alive at the start of age class “x”

Define the life table term “d_x”

The number of individuals who died during age class “x”

Define the life table term “l_x”

The proportion of starting population that survive to the start of age class “x”

Define the life table term “p_x”

The age class specific survivorship

Define the life table term “q_x”

Age class specific mortality

Define the life table term “L_x”

The average number of individuals alive during age class “x”

Define the life table term “T_x”

The population life expectancy; the number of years someone lives after age class “x’’ and the number of individuals in the population

Define the life table term “e_x”

The average life expectancy of individuals alive at the start of age class “x”

What scale do we base our life table graphs on?

Power of ten or logs

Define physiological ecology

Effect of abiotic (environmental) factors on species performance curve

What type of survivorship curve is this?

Type I Curve

What type of survivorship curve is this?

Type II Curve

What type of survivorship curve is this?

Type III Curve