Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
28 Cards in this Set
- Front
- Back
|
Density-Dependent vs. density-independent demographic effects |
Density-Dependent: starvation, overcrowding, disease, predation Density- Independent: will occur regardless of population density - rarely occur in nature -example- tornado |
|
|
Management Unit (MU) |
-A group with limited gene flow with other groups (similar to a DPS) *Reciprocal monophyly for m+DNA NOT required* *some differentiation in allele frequencies at nuclear genes* |
|
|
Ne |
-Effective population size - the # of breeding adults Ne=4NefNem/Nef+Nem Nef=breeding females Nem=breeding males |
|
|
How do we get new genetic variation into a population? |
1.) migration (immigration of new individuals)- very effective at counteracting loss of heterozygosity 2.) mutation- typical mutation rates too low to counteract loss of heterozygosity *mutation rate must be 1%/gene/generation or higher to prevent substantial loss of heterozygosity due to genetic drift |
|
|
Fixation |
When only one allele is present in population -results from bottleneck |
|
|
Evolutionary potential |
the ability to adapt to new diseases, changing environment, etc. -decreases as population/genetic variation decreases |
|
|
Extinction Vortex |
-When population are small, they are more susceptible to things that will make it smaller - inbreeding, loss of genetic diversity - reduced adaptibility, survival and reproduction -Reduced N - environmental variation - demographic stochasticity - catastrophes |
|
|
Morphospecies concept |
-morphological distinctiveness is the centerpiece - "a species is a diagnosable cluster of individuals within which there is a pattern of ancestry and descent" *created to classify bivalves *works well for fossils |
|
|
Minimum viable population (MVP) |
The smallest population size that has a "very high chance of persisting for the foreseeable future" -subjective *sometimes we have field data to estimate MVP, but more often have to rely on models |
|
|
Allee Effect |
Social and mating systems may break down when a population becomes too small --> the social dysfunction and failure to mate successfully that occurs when a population density falls below a certain threshold ex:- wolves = pack hunters... need hunters ex:- Queen conch = no reproduction with <50 individuals |
|
|
What questions can we answer with molecular "tools"? |
-Dispersal/Structure -Source of invasions/ colonisation routes -Hybridization/ introgression -Parentage/ mating systems -Level of diversity -Impact of habitat change |
|
|
Inbreeding Case Study: Florida Panther |
-Reduced to <30 individuals and isolated from other populations -Signs of inbreeding depression -kinked tailes - undescended testes - low survivorship of young -8 females translocated from Florida to Texas --> Reduction in signs of inbreeding depression -hybrid kittens 3x more likely to survive |
|
|
Arguments from Moritz paper |
1. That conservation actions should focus more on maintaining and restoring processes than on preserving distinct intraspecific phenotypes 2. Don't need to preserve every unique phenotype, because microevolutionary processes can recreate or replace specific adaptive phenotypes, so long as these processses are able to operate and the necessary genetic variation is present *Maintain Evolutionary Potential* |
|
|
Molecular "tools" (conservation genetics) |
Many different markers: - nuclear DNA sequences -AFLP -RAPD -minisatellites -microsatellites --> nucleus: DNA comes from both parents --> inherited from all ancestors -mtDNA sequences--> mitochondrion : DNA comes from mother --> DNA inherited from single lineage *can use mtDNA trees to look at relationships among species* |
|
|
Genetic Drift |
Changes in genetic composition of a population due to random sampling in small populations *influence of genetic drift inversely related to effective population size* |
|
|
Translocation Options (and problems that can result) |
1. Introduction= involves the establishment of populations outside the former species range - single source --> lack of adaptability, inbreeding depression - multiple sources --> out breeding depression 2. Reintroduction= involves the establishment of new populations within the former species range -single source --> inbreeding depression -multiple sources --> outbreeding depression 3. Augmentation= involves the translocation of individuals from a large population into a small population - Outbreeding depression |
|
|
Inbreding Depression |
-Reduction in reproduction, survival, or related characters due to mating of closely related individuals -some inbreeding can lead to blind/deaf/dead pups (recessive traits) |
|
|
Outbreeding Depression |
-Potential disadvantage of mixing stocks -Can cause loss of local adaption - Genetic incompatibilities --> Can't interbreed b/c of differences developed in isolation *generally much less of a concern than inbreeding depression* |
|
|
Bottleneck |
Sudden restriction in population size -less of a chance for alleles to survive/ get passed down |
|
|
Evolutionary Significant Unit (ESU) |
A population of organisms that is considered distinct for purposes of conservation - Delineating ESUs is important when considering conservation action *Must be reciprocally monophy letic for mtDNA *Needs substantial differentiation in allele frequencies at nuclear genes (does not have to be complete differentiation) |
|
|
Evolutionarily Significant Unit |
*ESU -A population that: 1.) Is substantially reproductively isolated from conspecific populations (usually based on genetic analysis) 2.) Represents an important component of the evolutionary legacy of the species *Not listed in ESA* |
|
|
Phylogenetic species concept |
-monophyletic clades is the centerpiece - the populations of each species should share a common ancestor problem= brown bears are polyphyletic, not monophyletic |
|
|
How do we use genetics to define ESU's and MU's |
-Need to know something about the mtDNA gene tree -->are there reciprocally monophyletic mtDNA clades? -Need to know something about distribution of allele frequencies betweeen population (are they strongly or weakly differentiated) |
|
|
Northern Elephant Seal vs. Southern Elephant Seal (bottlenecks) |
NES--> severe bottleneck -reduced to 10-30 individuals -now rebounded to over 100,000 SES- No bottleneck |
|
|
What are microsatellites? |
-short tandem repeats (2-6 bp) -highly variable among individuals in the number of repeats *very useful for looking at genetic variation over short time scales and small geographic distances, or among closely relation individuals |
|
|
Biological Species Concept |
-Reproductive isolation is the centerpiece of the BSC. --> the failure of populations to interbreed or form viable or fertile hybrids Problem- hybrids found in nature |
|
|
Different approaches to translocation |
-Typological Approach: maintain each phenotypically distinct population as a separate entity -No mixing of populations 1 2 3 -Phenotypic Approach: mix populations with similar phenotypes even if they have distinct histories 12 3 -Historical Approach: mix populations with distinct phenotypes but a shared history 1 23 |
|
|
Stochastic Factors (extinction vortex) |
-Harder to model --> directionality and magnitude isn't as predictable (varies year to year) -environmental variation - demographic stochasticity -catastrophes |
