Wildlife Exam 2

Populations are able to adapt to changing environmental conditions because individuals have _______ _________.

genetic variation

What do alleles do for genetic variability?

different combinations of alleles may allow individuals to maintain fitness under changing environmental conditions

What is fitness?

quantitative measurement of a genotypes reproductive success

What is reproductive success?

if an organism’s viable offspring produce viable offspring

Most alleles arise slowly through _________ in individuals, probably too slowly to affect most conservation issues

mutations

Maintenance of genetic diversity is considered important because it is linked to what?

positive outcomes for individuals and populations

In ______ populations, allele frequencies may change substantially from one generation to the next simply due to chance, based on random differences in the fitness of individuals

small

What happened to the northern elephant seals?

got bottlenecked

hunted until pop reached ~20 individuals

now population is around 220,000

surviving individuals do not represent the genetic diversity of the original population

What phenomenon happened to the northern elephant seals?

bottleneck effect

The chance of surviving a bottleneck is _______.

random

What happens to a rare allele in a large population vs a small population?

it will be maintained in the large population and will likely disappear in the small population

What is Ne?

effective population size based on the number of breeding individuals

What are factors in a population that affect Ne?

1) individuals that do not breed

2) variation in reproductive output among individuals

3) social structure

4) unequal sex ratios

What limits genetic drift?

migration

Immigration of even a few successful individuals from a genetically diverse population will limit what?

genetic drift

________ _________ declines relatively rapidly in small populations through genetic drift

Genetic diversity

What is genetic drift?

the change of frequency in an allele in a population due to random chance rather than natural selection

Population fluctuations greatly affect what?

Ne

For most species, population size __________ over time, some species more dramatically than others

fluctuates

Ne is somewhere between the highest and lowest numbers of breeding individuals, and is often closer to the ________

lowest

In general, the greater the variation in population size, the ______ the Ne.

lower

What is the equation for Ne?

Ne will be pulled strongly toward the _________ population.

smallest

On average Ne is only __% of total population size.

11

What does demographic variation affect?

persistence of small populations

What occurs in an ideal stable environment?

a population would increase to carrying capacity

Do individuals produce the average number of offspring?

no

What becomes more important when populations are small?

randomness in birth/death rates (demographic variation)

What affects demographic variation?

variation in produced offspring per individual and variation in death age

What affects ALL individuals in a population?

environmental variation and stochastic events

What is considered as environmental environmental variation?

nutrients, predation, parasitism, and disease

Stochastic events are often what?

unpredictable on the short term and inevitable over the long term

If the chance of a large event is 11% per year, how many events should be seen every 100 years?

one

Habitat is often ______ in distribution.

patchy

Patchy population distributions, if broad, may have benefits in terms of species _________ in the face of stochastic events

persistence

What is a classic metapopulation?

group of populations in patches with each population demonstrating independent dynamics, with some dispersal between patches

What is the main prediction of a metapopulation?

they should be more robust than independent populations

Who was Richard Levins?

A mathmatitian that made a model to track species immigration and emigration

When did Richard Levins make his model?

1969

What was Richard Levin’s model supposed to originally describe?

the population dynamics of insect pests across agricultural fields

What matters most (or at least one of the most important things) regarding population patches?

dispersal distance

What is the example animal for a classical metapopulation model?

Bighorn sheep

What is Bighorn Sheep dispersal affected by?

distance, topography, and barriers

What are barriers equivalent to? (ex highways)

adding distance

What are the physical effects of the fragmentation distribution of Desert Bighorn Sheep in the Mojave desert?

increase in number of patches

patch size decreases

patch isolation increases

What are the “organismal” effects of the fragmentation distribution of Desert Bighorn Sheep in the Mojave desert?

smaller populations

greater edge effect

greater isolation of individuals and populations (metapopulations)

What assessment was conducted on Desert Bighorn Sheep?

population genetic assessment

What are the 3 factors that explain the best fit model of genetic diversity?

distance

barrier effect

overall effect of anthropogenic barriers on genetic diversity

What is Nm?

estimates of migrants per generation

How many km is the barrier effect equivalent to between two populations?

40km

What is an anthropogenic barrier?

barriers resulting from human activity rather than natural processes

What do anthropogenic barriers seem to have caused?

rapid reductions in genetic diversity (up to 15%) in as few as 40 years

What was the combination that explained the best fit model for genetic diversity in Desert Bighorn Sheep?

distance and barriers

What were the ideas to mitigate sheep population fragmentation?

to build sheep overpass/underpasses

Were the sheep bridges successful? Which did they prefer

yes, overpasses

What is the caveat of the sheep bridges?

expensive

What is the potential positive of habitat fragmentation?

limiting the spread of disease

What does mycoplasma ovipneumoniae lead to sheep populations?

severe population declines

Sheep have ________ behaviors, meaning they learn from other sheep (such as how to cross the highway).

plastic

What occurs in patchy populations?

high levels of dispersal between patches and dynamics in patches are not independent

What is the idea of a mainland island/source-sink metapopulation?

stable population in large patch that supplies immigrants that maintain surrounds populations in smaller or poor quality patches

What is a non equilibrium metapopulation?

historical dispersal between population patches, but individuals no longer disperse among the populations

What types of mammals suffer from habitat fragmentation?

large wide ranging mammals

What is climate exposure?

how vulnerable to climate change a species is

What are climate projections used for?

to infer climate exposure based on predicted changes in habitat suitabilty

What are the 2 issues with climate vulnerability assessments?

1) overlook other components that could affect vulnerability ( ex adaptive capacity, phenotypic plasticity)

2) conducted at the species level (varies considerably among populations)

In broadly distributed species, various populations will likely be affected before the species as a whole goes ________.

extinct

Management decision that most directly influence species are often made at what level?

population level

Conservation efforts to mitigate the effects of climate change would benefit from information on what?

vulnerability at the population level

What does the sheep paper do?

combines genetic and landscape data to assess population level vulnerability of a broadly distributed species

What is the purpose of the sheep paper?

to inform management priorities for sheep on federal lands in and around 10 NP in the SW

What are the 5 population variables?

1) genetic diversity

2) genetic isolation

3) geographic isolation

4) maximum elevation

5) forward climate velocity

What is bighorn sheep dispersal and distribution affected by?

topography

barriers

distance

Where were the predominantly native populations in the sheep paper?

CA, AZ, and NV

Where were the predominantly reintroduced populations in the sheep paper?

UT

How many populations were studied in the sheep paper?

62

How many individual sheep were studied in the sheep paper?

1652

What are population level factors?

genetic diversity, isolation, and maximum elevation

What is genetic diversity as a population level factor?

increases fitness and persistence in many species

What is isolation as a population level factor?

negatively affects genetic diversity and negative effect on the ability to track climate

What is maximum elevation as a population level factor?

precipitation is positively correlated, increases persistence of sheep in Mojave (index of current climate stress)

Higher elevation typically means what?

better habitat

Where habitat was not discrete, populations were clustered based on what?

genetic data and expert opinion

Genetic data came from what?

microsatellite loci

What is landscape geographic isolation based on?

resistance

What is forward climate velocity?

measure of local speed and direction of climate change

What are the 2 emissions scenarios?

1) moderate which assumes cc policies will stabilize cc by 2100

2) high which assumes that greenhouse gases continue to rise

Where were the most unique sheep populations (genetic diversity)?

southern utah

What is the history of the sheep in southern utah?

almost all populations extirpated in late 1800s - 1940s, caused isolation and bottleneck

Where are the least genetically isolated areas (for sheep)?

Mojave, Death Valley, Lake Mead

Where is the most isolated sheep populations?

mountains surrounded by desert flats in southern mojave

When was the Earth created?

4.6 bya

Fossils have ages up to what?

3.45-3.77 bya

How old are photosynthetic cyanobacteria?

2.7 by

When did the pliocene cooling occur?

5.33-2.58 mya

What happened to the temperature during the Pliocene?

it lowered (at start temps were much warmer than today)

Why were the climates drier during the pliocene?

cold air does not carry as much water

When did the pleistocene begin?

2.58 mya

The pleistocene was a period of what?

great flux (temp, precipitation, currents, ice distribution, sea level)