We show that carotenoid-based colored ornaments can act as fitness signals because their intensity is positively correlated to both lifespan and lifetime fecundity.

airwise comparisons among treatments revealed that individuals with redder eye rings and bills survived better than paler individuals among control males,

We detected a positive correlation between the intensity of the red-carotenoid based coloration in both head ornaments and lifespan

restocking of wild populations

tightly-controlled steroid metabolism.

However, evidence of a correlation between the level of signal expression and these two fitness components are scarce, at least among vertebrates.

Captive conditions allowed us to reliably establish both lifespan and paternity, as each male was individually housed with a female every reproductive season. Some of these males were treated throughout reproductive life with testosterone, vs those with anti-androgen compounds.

We previously found that wild birds mate assortatively according to trait redness [65], and captive females that mated with males whose carotenoid-based ornaments (red eye rings and bill) were artificially intensified laid more eggs [66]. These results suggest that these traits evolved as sexual signals involved in mate choice, and influenced post-mating resource allocation decisions in females.

Sexual selection

we might expect a strong covariance between an ornament and male mating success.

This model requires at least 3 traits (i.e., ornament, preference, and a viability trait), so it is clearly distinct from the Fisherian model (Maynard Smith, 1991). In the condition-dependent indicator model, the ornament is a costly condition-dependent trait. Thus, males closer to the optimum with respect to the viability trait will be in better condition and will be able to maintain a more elaborate version of the ornament (Zahavi, 1975, 1977). Female choice evolves because females choosing males with more elaborate ornaments produce offspring with higher viability or that will be in good condition as adults.

This model involves a single preference trait in females and a single ornament trait in males (ignoring multivariate preferences and signals for the moment).

n some species, the males appear to provide nothing to the females but sperm, yet they have elaborate ornaments for which females show preferences (Taylor and Williams, 1982; Reynolds and Gross, 1990; Kirkpatrick and Ryan, 1991; Kokko et al., 2003). These systems are especially perplexing from a sexual selection standpoint because the benefits of choice are not at all obvious.

The higher-quality females are ready to breed before the lower-quality females, and they choose to pair with the higher-quality males (Fig. 9.1C).

it gave the impression that animals would need a human-like sense of aesthetics for sexual selection to operate.

Here we will treat female choice, while keeping in mind that Darwin knew that in some systems mirror-image processes could occur through male choice. Sexual selection as a consequence of female choice is easy to understand, provided we are willing to accept that female preferences exist. If females show a preference, then males with the preferred trait will leave greater numbers of offspring, and their trait values will tend to increase in frequency in the population.

that many important questions regarding sexual selection remain to be answered.

The first theme concerned the question of why sexual selection occurs in the first place. In the context of this question, Darwin identified the 2 major categories of sexual selection, namely intrasexual and intersexual selection, although he didn’t use those terms (Darwin, 1871). The second theme is related to the question of why sexual selection is strong in some lineages but not others. This question continues to be a major theme of modern research, but Darwin expressed an amazingly modern, intuitive understanding of some of the explanations for the patterns of sexual selection among diverse evolutionary lineages (Darwin, 1871).

onstructed his literary works with a clear argument in mind and marshaled vast amounts of evidence to support his case.

well advised to revisit his works.

Sounds obvious, but if you were to sue an oil company for the suspected killing a loved one via cancer, you would need a little more legal ammunition than "it just makes common sense" against an army of corporate lawyers.

Their research found that 75% of the chemicals could affect the skin, eyes,and other sensory organs, and the respiratory and gastrointestinal systems. Approximately 40–50% could affect the brain/nervous system, immune and cardiovascular systems, and the kidneys; 37% could affect the endocrine system; and 25% could cause cancer and mutations.

In the aftermath of the spill, ExxonMobil has disclosed that the pipeline has been transporting tar sands oil from Alberta, Canada, which is a low grade, more toxic and corrosive type of oil.

Storage of the waste water is currently under the regulatory jurisdiction of states, many of whom have weak to nonexistent policies protecting the environment.

Fissures created by the fracking process can also create underground pathways for gases, chemicals and radioactive material.

Crystalline silica, in the form of sand, can cause silicosis (an incurable but preventable lung disease) when inhaled by workers. Sand is a main ingredient used in the fracking process. The National Institute for Occupational Safety (NIOSH) collected air samples from 11 fracking sites around the country. All 11 sites exceeded relevant occupational health criteria for exposure to respirable crystalline silica. In 31% of the samples, silica concentrations exceeded the NIOSH exposure limit by a factor of 10, which means that even if workers were wearing proper respiratory equipment, they would not be adequately protected.

124 parts per billion compared to the worst air day of the year for Los Angeles, at 114 parts per billion. The Environmental Protection Agency's maximum healthy limit is 75 parts per billion.

NOAA scientists found the Weld County gas wells to be equal to the carbon emissions of 1-3 million cars.

25 times more potent in trapping heat in the atmosphere than carbon dioxide.

Since each well can require up to 8 million gallons of water, and up to 40,000 gallons of chemicals, a well site may need up to 2000 tanker truck trips, per frack. A well can be fracked up to 20 times.

Methane pollution and its impact on climate change

The drilling is then angled horizontally, where a cement casing is installed and will serve as a conduit for the massive volume of water, fracking fluid, chemicals and sand needed to fracture the rock and shale.

Halliburton loophole.

nvolves the smashing of rock with millions of gallons of water--along with sand and a undisclosed assortment of chemicals in order to bring gas to the surface.

developed in the late 1940s to gain access to fossil energy deposits previously inaccessible to drilling operations.

Evolutionhas no purpose

However,remember that the intermediate phenotype, a medium-colored coat, is very bad for the mice—they cannotblend in with either the sand or the grass and predators are more likely to eat them.

the trait is an honest signal of the males’quality, thus giving females a way to find the fittest mates— males that will pass the best genes to theiroffspring

The good genes hypothesis states that males develop these impressive ornaments to show off their efficientmetabolism or their ability to fight disease. Females then choose males with the most impressive traitsbecause it signals their genetic superiority, which they will then pass on to their offspring.

he speculation is that large tailscarry risk, and only the best males survive that risk: the bigger the tail, the more fit the male. We call this thehandicap principle

emales tend to have a greater variance in their reproductive success than males and arecorrespondingly selected for the bigger body size and elaborate traits usually characteristic of males

Males are often larger, for example, and display many elaborate colors and adornments,like the peacock’s tail, while females tend to be smaller and duller in decoration. We call such differencessexual dimorphisms (Figure 19.10), which arise in many populations, particularly animal populations, wherethere is more variance in the male's reproductive success than that of the females.

orange beats blue, blue beats yellow, and yellow beats orange

Each of these forms has adifferent reproductive strategy: orange males are the strongest and can fight other males for access to theirfemales. Blue males are medium-sized and form strong pair bonds with their mates. Yellow males (Figure 19.9)are the smallest, and look a bit like females, which allows them to sneak copulations.

ISUAL CONNECTIO

Large, dominant alpha males use bruteforce to obtain mates, while small males can sneak in for furtive copulations with the females in an alphamale’s territory. In this case, both the alpha males and the “sneaking” males will be selected for, but medium-sized males, who can’t overtake the alpha males and are too big to sneak copulations, are selected against.

intermediate phenotypes are, on average, less fit.

Similarly, the hypothetical mouse population mayevolve to take on a different coloration if something were to cause the forest floor where they live to changecolor. The result of this type of selection is a shift in the population’s genetic variance toward the new, fitphenotype.

When the environment changes, populations will often undergo directional selection (Figure 19.8), whichselects for phenotypes at one end of the spectrum of existing variation.

tabilizing selection

Scientistscall this concept relative fitness, which allows researchers to determine which individuals are contributingadditional offspring to the next generation, and thus, how the population might evolve.

It selects for individuals with greatercontributions to the gene pool of the next generation. Scientists call this an organism’s evolutionary(Darwinian) fitness.

if that same individual also carries an allele that results in a fatal childhood disease,that fecundity phenotype will not pass to the next generation because the individual will not live to reachreproductive age.

adaptive evolution.

different forces can lead to different outcomes

Explain the different ways natural selection

Rare long-distance movements of finches in the archipelago have been detected before, but, until recently, it was assumed these birds were vagrants that did not stay to breed (16–18).

Theexistence of"livingfossils" and theoccurrenceof"explosivespeciation"infreshwaterlakes has long been acceptedas evidence fordrasticallyunlike rates ofevolutionandspeciation.

Theextreme in-breedingof the ensuinggenerationsnotonly leads toincreasedhomozygositybutalso exposesmanyifnotmost of the re-cessive alleles (now made homozygous) toselection.

whatsoeverof the occurrence ofa drasticevolutionaryaccelerationandge-neticreconstructioninwidespread,pop-ulous species.

Much of thecurrentconflictaboutthe validity ofpunctuatedequilibriais actually the subconsciousperpetuationof the oldambiguityas towhatspeciationreally is.

Saltationismbecame even morepopularafterthepublicationsofBateson(1894)andde Vries (1901-1903)

ButDarwin,atthattime, wasvirtuallyalone in this insistenceongradualism(as far as I know the liter-ature).Virtuallyallotherevolutionistsofhis period were soimpressedby the gapsbetweengeneraandby the evengreatergaps among thehighertaxathatthey feltthey couldnotdowithoutsaltations.

adaptive radiation generally means an event in which a lineage rapidly diversifies, with the newly formed lineages evolving different adaptations.

The four basic evolutionary mechanisms — mutation, migration, genetic drift, and natural selection — can produce major evolutionary change if given enough time.

As this map shows, sparrows in colder places are now generally larger than sparrows in warmer locales.

It can be a frequent or rare event within a lineage, or it can occur simultaneously across many lineages (mass extinction). Every lineage has some chance of becoming extinct, and overwhelmingly, species have ended up in the losing slots on this roulette wheel: over 99% of the species that have ever lived on Earth have gone extinct. In this diagram, a mass extinction cuts short the lifetimes of many species, and only three survive.

Just as in microevolution, basic evolutionary mechanisms like mutation, migration, genetic drift, and natural selection are at work and can help explain many large-scale patterns in the history of life.

a macroevolutionary lens might require that we zoom out on the tree of life, to assess the diversity of the entire beetle clade and its position on the tree.

50 m upstream of its confluence with Big Run. A second antenna array was located at the upstream extent of our study area on Upper Big Run (within section 3). At each location, two pass-by antennas constructed of high-density polyethylene were anchored to the stream bottom and operated between June 2011 and September 2013 [45]

Stationary PIT antennas were operated at two sites within the study area to detect fish movements that would have gone undetected using only a mark-recapture study design (Fig 1; [44]).

We used multistate Cormack-Jolly-Seber models implemented in program MARK [46] to estimate stage-specific survival rates for Brook Trout.

Based on four years of electrofishing surveys, we generated individual encounter histories for 2,973 fish representative of the two streams

Downstream of the confluence of Monroe and Big Run, some fish showed signs of intermediate ancestry (e.g., Q = 0.46 and Q = 0.48)

Overall, 1.22% of the observed molecular variance could be attributed to differences between upper tributaries (AMOVA).

Bayesian genetic clustering showed support for at least two genetic groups that inhabit the study area,

Additionally, restoration and reintroduction activities may be more successful if the population structure is understood, especially when dealing with species known for high amounts of genetic divergence such as Brook Trout.

However, it is important to recognize and conserve the underlying population structure, as the subpopulations may represent local adaptation and reservoirs of genetic diversity.

genetic exchange between the two streams show a small but non-zero degree of connectivity. Thus, exchange occurs between streams, but introgression rates are typically limited to a few immigrants per generation.

The physical movement patterns exhibited by these groups appear to limit the potential for genetic exchange between streams, reinforcing the observed genetic structure.

Similarly, young-of-the-year survival rates ranged from 27.2–42.0% and were similar among the streams in 2011 and 2012 (Fig 5). Unfortunately, low recruitment in 2010 prohibited meaningful estimates of young-of-the-year survival rates for both streams.

Brook Trout in Upper Big Run grew significantly faster than conspecifics in Monroe Run, but the effect size was small (5.6 mm/y faster at a given length; P < 0.05). Overall, stream reach accounted for 4.8% of the observed variation in growth rates.

Most of the detections were due to a few individuals that were repeatedly detected.

rook Trout initially tagged in Monroe Run (1,058 individuals) were never captured during electrofishing surveys in Big Run above the confluence (Table 5).

For the purposes of this manuscript, we chose to focus our remaining analyses on contrasting fish in Big Run with those in Monroe Run, reflecting the highest level of genetic structure observed.

has been identified as a regionally important population stronghold.

we found significant differences in growth rates (ANCOVA; P < 0.05) between individuals in Big Run and Monroe Run for each of the three years of record. Brook Trout in Big Run (sections 1–3) consistently grew faster (overall 7.8 mm/y faster at a given length; P < 0.05) than in Monroe Run (sections 4–5; Fig 4).

e implemented a Bayesian coalescent model in MIGRATE and estimated θ and M, where θ represents the mutation-scaled effective population size (4Neμ) and M represents the mutation-scaled immigration rate (m/μ), where m is the proportion of migrants per generation and μ is the mutation rate per locus per generation [41], [42].

Each model run allowed admixture used correlated allele frequencies, and consisted of a burn-in period of 500,000 steps followed by 500,000 iterations that were used for data collection.

We used GENALEX, version 6.501 [29], [30], to determine if Brook Trout collected within a stream reach appeared to conform to Hardy-Weinberg equilibrium, based on a Bonferroni-adjusted critical P-value (0.0008; α = 0.05). GENALEX was also used to calculate pairwise FST and G”ST [31], [32], values among collections in different stream reaches, and conduct analysis of molecular variance (AMOVA) [33].

Prior to any subsequent analysis, we used COLONY 2.0.5.0 [28] to identify individuals with full-sibs represented in the sample. Where they occurred, full-sibs were randomly removed from the dataset (n = 24) until only a single family representative remained in each section.

We selected 250 Brook Trout from across the study area for genetic analysis. Individuals were chosen using a stratified random sampling design where about 50 individuals were selected from each of five stream reaches, representing a mixture of stationary and mobile individuals.

Widespread declines have attracted attention, and millions of dollars are spent annually on the conservation and restoration of Brook Trout. These management activities have frequently been met with unexpected results (e.g. [26]), potentially as the result of misunderstanding population structure and function.

For example, groups of populations may exhibit a portfolio effect, potentially obscuring the declines of individual populations [7], and calling for population-specific management or policies which broadly protect the fishery resources.

In contrast, streams are highly dynamic linear environments with limited connectivity between adjacent watersheds [9], [12], [13]. Under these conditions, heterogeneity in stream networks is expected to contribute strongly to population structure [14].

While outright barriers to dispersal bound populations, biotic and abiotic factors may restrict connectivity between groups of individuals [9], [10], and lead to patterns of population isolation by ecological features of the landscape rather than purely by geographic distance (e.g. isolation by resistance [11]).

We found evidence for limited genetic exchange across small spatial scales and in the absence of barriers to physical movement.

a single population with genetic isolation-by-distance, or a metapopulation.

how to define a population.

The southernmost part of Balkans has played a major role as a glacial refugium for A. astacus. Such refugia have served as centres of expansion to northern regions. Recent history of the noble crayfish in southern Balkans reveals the influence of environmental (climate, geology and/or topology) and anthropogenic factors.

The species divergence has been shaped by geological events (i.e. Pleistocene glaciations) and humanly induced impacts (i.e. translocations, pollution, etc.) on its populations due to species commercial value and its niche degradation.

Mosquito populations have evolved so that slightly shorter days are required as a cue for going dormant.

House sparrows were introduced to North America in 1852. Since that time the sparrows have evolved different characteristics in different locations. Sparrow populations in the north are larger-bodied than sparrow populations in the south.

although since any particular mutation is rare, this process alone cannot account for a big change in allele frequency over one generation

Mutation, migration, genetic drift, and natural selection are all processes that can directly affect gene frequencies in a population.

determine that 80% of the genes in the population are for green coloration and 20% of them are for brown coloration. You go back the next year, repeat the procedure, and find a new ratio: 60% green genes to 40% brown genes.

microevolution — evolution on a small scale

the field of evolutionary medicine is also concerned with suggesting strategies for slowing the evolution of resistance in pathogen populations [28]–[30];

For example, genomics, which emerged mostly from molecular biology, is now steeped in evolutionary biology.

The availability of genomic data from a remarkable range of species has allowed the alignment and comparison of whole genomes.

Past evolution, for example, can be inferred from samples derived from ancient specimens, archived material in museum collections, lake sediments, and glacier cores.

the more complete incorporation of the roles of epigenetics, behavior, and plasticity in models of trait evolution; analysis of units of selection; and attempts to construct a quantitative and predictive theory that describes the genetic basis of adaptation.

Evolutionary methods, particularly population genetics, are now used frequently in forensics and court cases to test the link of crime scene evidence to individuals [60], and phylogenetic analyses have been vetted and accepted as valid and appropriate methods for determining facts of history in the United States criminal court system [61].

Unfortunately, genetically modified crops are genetically uniform and so do not represent a long-term solution against the evolution of either herbicide or Bt resistance.

The green revolution, from the 1950s onwards, rested on selective plant breeding for larger yields and was underpinned by evolutionary theory [36].

In addition, some age-related conditions, such as cancer, can be understood as the outcome of selection for early reproduction, when humans faced dying of disease or predation at an early age.

And the impact of evolutionary biology is extending further and further into biomedical research and nonbiological fields such as engineering, computer sciences, and even the criminal justice system.