Flashcards in Week 3 Deck (18):
What is the difference between primary, secondary and tertiary scientific literature? What do they all have in common?
Primary literature = peer-reviewed information, highly technical communication reporting on original research findings, scientists communicate with other experts in the field. Secondary Literature = peer-reviewed information, technical communication synthesizing original research findings (i.e. review articles), scientists communicating with other educated by not necessarily experts in the field, can trace research back to its original source; Tertiary Literature = peer-reviewed information, less technical communication (i.e. textbook), authors communicate with general population, may not be able to trace source of information back to original source.
Consider two traits that have different heritability values. How can selection act on these traits? Will it differ?
R = Response to Selection = (H^2)*S. The strength of selection and response to selection will dictate how rapidly phenotypic changes are observed in populations over time, traits with high heritability respond to natural selection more rapidly than traits with low heritability
Quantitatively, what is the difference between absolute and relative fitness?
Absolute fitness = number of the genotype after selection/ number of the genotype before selection. Relative fitness = absolute fitness of a genotype/absolute fitness of the best genotype
What is the difference between the censused and effective population size? Why might they differ?
Nc = censused population = what you actually count. Ne = proportion of an actual population that mates randomly. Ideal populations would have Ne = Nc but this is often not the case because: (1) unequal numbers of males/females, (2) not all individuals reproduce, (3) the number of offspring produced differs from random expectations, (4) mating is not random, and (5) the number of breeders changes from one generation to the next
What is the difference between an endangered and threatened species? How does effective population size inform that status?
Endangered = any species that is in danger of extinction throughout all or a significant portion of its range; Threatened = any species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. Effective population size can be used as a predictor of long-term population "health" and persistence.
For grizzly bears in Yellowstone National Park, how do census and effective population size values compare?
The census population size is always above the effective population size
What is a population bottleneck and how does the genetic diversity of the population following the bottleneck compare with that preceding it? Why is this important?
Bottlenecks = evolutionary events in which a large portion of the population is lost or prevented from breeding; the genetic makeup after the bottleneck may not represent the diversity that was present before; in the case of cheetahs, it led to inbreeding, resulting in unusually low genetic variability among individuals, low reproductive sucess due to highly abnormal sperm and low sperm count
What is a founder effect? How might it influence the genetic differentiation of a population relative to its source population?
Founder effect = founding population has different genetic makeup than source population they were derived from; the new population will be dominated by the genetic features present in the founding members, thus the new population experiences evolution
What is inbreeding and why is it potentially deleterious?
Inbreeding = matings between relatives, results in unusually low genetic variability among individuals, low reproductive success (highly abnormal sperm, low sperm count)
What is a biological species?
Group of interbreeding organisms that have an isolated gene pool, groups of interbreeding populations that are evolutionarily independent of other populations, the base unit of taxonomic classification consisting of an ancestor-dependent group of populations of evolutionarily closely related similar organisms, individuals capable of interbreeding with each other to produce fertile offspring
Why is the number of species on the planet NOT static?
New ones are added from fossils and living organisms
Among recognized animal species, which group contains the largest number of species?
If you think you discovered a new species of flowering plant and a new species of beetle, how would you go about getting them recognized as new species? Would you have to do anything different from the recognition of the two discoveries?
(1) description of new species - must define what features (behavior , anatomy, genetic) mark it out as being unique/new, must allow it to be distinguished from close relatives, details of the origins of the species type/subtypes (alternative lifestyles, color patterns, etc) must also be given; (2) How/where/when were they collected; (3) In what kind of environment were they collected from (fossilized in rock, etc) - description must be published in a form that is internationally accessible and archived in multiple location
What are subspecies?
Group of phenotypically similar populations of a species inhabiting a geographic subdivision of the range of that species but differing taxonomically from other populations of that species, not distinct enough to become reproductively isolated (unable to produce fertile offspring), but may be on the path to reproductive isolation + speciation
In order for Fennessy et al. to propose that the giraffes of Africa belong to four separate species, many genetic analyses were conducted. One of these was microsatellites. What are microsatellites and what is their utility? Using microsatellites alone from previous analyses, how many subspecies of giraffes are there?
Microsatellites are a tool for genetic analysis, identified 30+ years ago, tandemly repeated DNA motifs of various lengths (<10 bps), commonly As/Ts, present in prokaryotes/eukaryotes, in eukaryotes, present in nuclear coding/noncoding regions, chloroplasts, and mitochondria, can be amplified by PCR making them easy to make lots of copies for analyses
What are haplotypes and what is their usefulness in genetic analyses?
Combinations of gene variants usually single nucleotide polymorphisms(SNPs), that are likely to be inherited together within the same chromosomal region, areas are less prone to recombination than would be expected by chance therefore conserved as a sequence over many generations, can be used for genetic analyses
Fennessy et al. used coalescence theory to generate a plausible genetic tree for the African giraffe species. What is it and what assumptions does it make?
Merging of genealogical lineages back in time until they converge on common ancestor, tool for characterizing evolutionary relationships and effective population size, assumes null hypothesis = genetic drift/estimate of mutation rate, generates evolutionary tree of genes as hypothesized relationships among organisms. Hypothesized trees: larger the population size, shorter the phylogenetic branch, lesser the chances to coalesce before a speciation event