Participants with Parkinson's disease have deficits in learning from trial and error. They also had difficulty learning from a positive outcome. Dopamine administration allowed participants with Parkinson's to learn from both positive and negative outcomes, suggesting that their impairment resulted from depletion of dopamine in the basal ganglia.

Impulsivity in rats’ behavior is what leads to compulsive cocaine-seeking behavior despite negative outcomes.

Animals under dopamine depletion or blockade respond to fear conditioning by urinating, but they fail to respond by avoiding electric shock. These animals show a deficit in initiating a response, but they do not show deficits in their ability to learn associations.

Rats who were given cocaine respond normally to tasks that are meant to completely remove an association with a stimulus. However, they did not respond normally to tasks that were meant to devalue an association with a stimulus, suggesting they were unable to use new information about consequences to guide their behavior.

Exposure to ultraviolet (UV) radiation is a risk factor for the development of melanoma. Researchers have shown that people who sunburned in childhood are at a greater risk of developing melanoma than are people who sunburned in adulthood. This study suggests that age is associated with the susceptibility of skin to environmental carcinogens.

Mutations in genes that code for Edn3 result in deficiencies in melanocytes. Edn3 serves as a stimulator of melanoblast proliferation and differentiation. When melanoblasts differentiate, they become melanocytes.

Researchers have shown that individual melanocytes produce multipotent cells that are able to regenerate during consecutive subcloning. This indicates that the multipotent cells display stem cell qualities. Edn3 encourages the maintenance of the multipotent cells. Moreover, Edn3 stimulates the proliferation of melanoblasts, which are the precursors of melanocytes.

Cells proliferate in the presence of Edn3. The cells that are produced are melanoblasts, which subsequently become melanocytes.

Researchers isolated Edn1 to determine its function. Edn1 was shown to be responsible for an increase in blood pressure. Expression of the gene was controlled by factors that affect blood vessels, suggesting that there is a cardiovascular control system.

Plastic pollution in the ocean has been known to be a problem for a long time.

This early work (reference 1) looked at which types of pollutants might pose a future threat to ocean resources and mechanisms of how each pollutant ended up in the ocean.

The work of Jablonski and Chaplin strongly supports the theory that melanin pigmentation in human skin is an adaptation that helps regulate the amount of UV radiation that gets into the epidermis, with different populations having different selective pressures based on their environments.

They argue that protection against UV breakdown of nutrients (such as folate) was the primary selective agent that led to darker pigmentation of people living near the equator, because folate is closely linked to reproductive success in humans.

Jablonski and Chaplin also argued that skin pigmentation is so responsive to environmental conditions that it is not valuable when assessing the genetic relatedness of human groups.

Table 2 shows the area, dimension, year of census, aboveground tree biomass, species richness, and stem density in plots that are permanently placed in six Neotropical Forests. This is pre-existing information.

Biodiversity experiments have been performed on tropical forests and it has been concluded that they are a large portion of the Earth's biodiversity.

This is from a journal: Applied Ecology. The author discusses climate change and how it is negatively impacting global ecosystems and how not much is being done to alleviate the problem.

This is a report commissioned by the EDF. It is an analysis on the consequences of letting climate change continue unchecked on the economy of Florida.

The objective of this study was to measure the hydrometerological and hydrological aspects of Esteros del Ibera.

This author's research is focused on wetlands and global climate change impact on them.

The author's research centers around the global impact of climate change on the world. He brings into question how wetland systems (most vulnerable) will be impacted and how, if there is a way to save them.

Everglades: The Ecosystem and Its Restoration. This book summarizes recent studies on the vegetation, alligators, wading birds, and endangered species. It also covers the physical driving forces that created and continue to shape the everglades and patterns and processes of its flora and fauna.

See Dr. Margaret McFall-Ngai discuss the daily behavior patterns of the bobtail squid and why counterillumination is important for its survival:

Daily behavior of the Hawaiian bobtail squid.

The lux genes in Vibrio fischeri code for the proteins that produce bioluminescence.

Visick et al. (2000) created three mutant lux genes that were unable to produce bioluminescence. The mutant strains of V. fischeri carrying the modified genes were used to test whether bioluminescence was a key factor in development from juvenile to adult.

Crookes et al. (2004) determined that the composition of reflective tissue found in the tissues of E. scolopes was different from the composition of reflective tissue commonly found in other animal tissues.

In most animals, the reflective tissue is composed of thin layers of purine crystals, which are able to bend light (i.e., they have a high refractive index). The reflective tissue in E. scolopes is composed of a group of proteins high in methionine, tyrosine, arginine, and tryptophan.

See Dr. McFall-Ngai discuss the structure of the light organ and the symbiosis with Vibrio fischeri. She also discusses how the light organ is able to modulate the amount of light produced by the Vibrio to match down-welling light:

Structure of the light organ

In many organisms, the ability to sense light is especially important for allowing organisms to sync to the various rhythms of light in the environment, e.g., daily, monthly, or yearly rhythms.

This has allowed for the diversity of structures other than the eye that can sense light. Researchers are still working to learn more about about these structures.

Opsins are a group of proteins that are sensitive to light. There are many different forms of opsin, and they are involved in both visual and nonvisual systems throughout the animal kingdom.

Some opsins bind to retinal (a chemical involved in animal vision) and undergo a change in their structure when subjected to light.

This change in conformation is the signal that initiates the series (cascade) of proteins in the retina responsible for the ability to see (this process is called phototransduction).

Two different research groups used the same population to look for genetic determinants of both skin and eye pigmentation in a population of people in Cape Verde. In this population, there has been extensive admixture (interbreeding) between European and African populations.

OCA2 was identified as being related to both skin and eye pigmentation, and another overlapping variant with this study, SLC24A5, was identified as being associated with skin pigmentation. Further work identified two additional genes associated with skin pigmentation; one (DDB1) was also a candidate gene in this paper.

Liu et al. perform a GWAS study similar to those performed in this paper, looking for genetic variants that correlate with skin pigmentation in a population of European people.

They identify 9 genes that may be associated with skin pigmentation in Europeans, one of which (HERC2/OCA2) overlaps with the genes identified in this study as being associated with skin pigmentation in Africans.

Harding et al. sequence the MC1R gene in individuals from Europe and Africa, and by a variety of statistical tests they determine that the gene is under purifying selection (selective removal of alleles that are deleterious, in this case, alleles that lead to reduced melanin) in Africa, but not Europe.

Wood et al. analyze multiple independent studies to identify the SNPs that are most strongly associated with adult height (in Europeans).

They identify thousands of variants that are associated with height, and even with the top ~9500 SNPs they can only explain ~29% of height variance.

Their work also suggests that increasing the number of individuals in a GWAS analysis will initially suggest new variants, but will eventually reach a point of "saturation" where new variants will highlight the same genes that have already been seen.

Bellono et al. identify OCA2 as being essential for eye and skin pigmentation. The gene encodes a protein that is a transmembrane channel in the membranes of melanosomes which allows passage of chloride out of the melanosome, thereby regulating melanosome pH.

Bellono et al. find that this passage of chloride ions out of the melanosome is essential for melanin formation, and changing the function of OCA2 by mutations that have been identified in albinism (a condition characterized by lack of melanin) reduces melanin formation.

Li et al. develop and perform ChIA-PET (Chromatin Interaction Analysis by Paried-End-Tag sequencing), a method to identify regions of chromatin that interact with each other at higher resolution than previous methods.

Using this method in MCF7 cells (a breast cancer cell line), they identify interactions between the location of several variants of interest to Crawford et al. with the promoter of the gene DDB1.

Prior research used positional cloning (a genetic tool used to identify regions of the genome before sequencing was widely available), morpholino knockdown (a way to reduce specific protein levels), and DNA and RNA rescue, to identify a mutation in slc24a5 as being responsible for the reduced pigmentation phenotype of "golden" mutant zebrafish.

They also analyzed human data and identified a SNP in the coding region of SLC24A5 that was present at highly different frequencies in European and African populations, suggesting that it may have been the target of selection, and may be associated with skin pigmentation.

In the paper by M. Williamson, islands are subjected to introduced predators and the environment was monitored. Clusters of islands are ideal for demonstrating top down trophic cascades because similar ecosystems may be differently impacted by a single variable (with or without the top predator) and the insular ecosystems prevent the spread of the predator. The procedure of the two different predator locations allows for accurate monitoring of the different island ecosystems.

Nerem and coauthors found that during the 1997–1998 El Nino event there was a 20 mm rise and subsequent fall of mean sea level was observed. As these changes occurred alongside a rise and fall of global mean sea surface temperature anomalies, their work suggests the observed mean sea level change is mostly caused by thermal expansion.

Thermal expansion means that as water warms it expands to take up more space, which causes sea levels to rise.

For more information about thermal expansion watch this video from AsapScience: https://www.youtube.com/watch?v=fuvY5YG5zA4

Broadbent et al. focused on ecological changes caused by fragmentation. They determined that edges of a range are dominant and affects tree mortality, microclimates, and other aspects of tree communities; surrounding fragments may show differences in vegetation.

This influenced the decision to look at gap edges and centers for the study.

Global change and species interactions are the focus of this study. Discusses how functional trait attributes emphasize global changes.

Williams found that 51% (301) of Brazilian pepper trees analyzed had a eastern haplotype and 49% (291) had a western haplotype.

Haplotypes are a set of DNA variations that tend to be inherited together.

Wheeler's paper looked at the impact that Megastigmus transvaalensis had on the Brazillian Peppertree's Drupes. The wasp was found at all 18 sites surveyed containing the Brazilian Peppertree. The wasp damaged 23.5 ± 2.8% of the drupes during 1997–1998 and 38.5 ± 4.2% of the drupes during 1998–1999 in the winter. During the spring fruit production period, 76.3 ± 3.6% of the drupes were damaged by the wasp in 1998 and 74.8 ± 3.4% during the same period of 1999.

A survey of the Brazilian peppertree variance, was attained through spatial genetic and geostatistical research. Concluding with a history of dispersal, beginning with a short diffusive dispersal from South Florida, in where significant dispersal among intra-specific species is evidenced, instating long-distance jumps to North Florida.

Hardiman and Culley examined hybrid populations of the Callery Pear (Pyrus calleryana) in two different generations. They compared transpiration, stomatal conductance, and water use efficiency. In transpiration and stomatal conductance the advanced generation hybrids did better than the new hybrids but the advanced generation did worst in water use efficiency compared to the newer hybrids.

Kolbe's paper looked at the evolutionary history regarding hybridization in lizards of the Galapagos islands.

Facon's study looked at the evolutionary history of snails.

Rieseberg's study looked at hybridization patterns in annual sunflowers.

Dlugosch and Parker 2008- Surveyed the importance of or lack of genetic diversity among founding populations.

http://www.journaloffloridastudies.org/0102peppertree.html

Brazilian peppertree: a poster child for invasive plants in Florida

V. Manrique, University of Florida

J. P. Cuda, University of Florida

W. A. Overholt, University of Florida

This article provides an ample description of the impact that the Brazilian pepper tree is having on Floridian land. The article also provides information on measures being taken in order to control the species.

Stockwell et al. 2003- Discusses issues: (1) alternative perceptions of “evolutionary” and “ecological” time, (2) the role of contemporary evolution as an ecological process, (3) fitness as a bridge between evolution and conservation, and (4) challenges faced by conservation strategies based on gene flow estimation or manipulation.

The mutation to NHE9 is also similar to a mutation in NHE6, which has been linked to a patient who exhibited symptoms of autism and epilepsy.

In the patients with epilepsy and autism, the authors found a NHE9 mutation that is similar to a mutation in Nhe1 that causes epilepsy in mice.

Mice with this mutation, called swe mice (which stands for slow-wave epilepsy mice), were the first mouse models of human generalized epilepsy.

Disrupted NHE9 has been found in a family with a developmental neuropsychiatric disorder and mild intellectual disability.

The fact that disrupted NHE9 has been found in multiple patients with neuropsychiatric disorders suggests it may be a cause of these.

Here, the authors compare their findings to other studies of de novo CNVs. They show that their results are similar to previous studies (such as Sebat et al.) that established the detection of de novo CNVs as a way to identify genes linked to autism.

Hoodfar and Teebi studied the link between inbreeding and the prevalence of different genomic abnormalities.

IThey found that the prevalence of autosomal recessive disorders was more than doubled in consanguineous families.

Studies have shown that there are many unique combinations of mutations that can cause autism, as is the case with intellectual disability and epilepsy.

Unfortunately, given that there are so many ways for autism to occur, it is difficult to identify all of the mutations and changes that can lead to symptoms.

Data supports the fact that autism is linked with several genomic regions. Nnew regions are still being identified today.

Autism is associated with intellectual disability (formerly called mental retardation*) about 70% of the time, and males are more often diagnosed.

There is no evidence that social class has an impact on the incidence of the disease, but there is not enough data to know if race or ethnicity influence the incidence of autism.

There is also no available data to support the idea that incidence of autism is changing over time.

*For more on the movement to change the language of disability, see the Wall Street Journal.

Several research teams have worked independently to identify loci that could be responsible for autism. However, this has been difficult due to the high number of genes that could be involved and the high variability between affected individuals.

Results were different from previous research who showed that one species were pollinated by long, thin mouth parts.

The author is explaining that the pollination of the species "Euglossine" has been experimented on before. With this being said, the previous work tested these bees and how they interact with plants.

In the above article, the author is specifically experimenting on this family of bees and how they interact with A. berteroi in the pine rockland environment. The author is more concerned with how these bees interact with this specific plant.

This study site was a part of a previous experiment. In the previous experiment, the study site was chosen due to the abundance of individuals that were present. Essentially, the area with a higher abundance of individuals is beneficial to the experiment. It is beneficial to use previous work as a reference, especially if there is a common factor.

Floral tube length in hawkmoth-pollinated plants will determine which insect will transfer pollen. if it is too short or too long they will not be effective.

The structure of the insect determines the effectiveness of the pollination as well as the shape of the flower like the length of mouth part and floral tube.

Most plants show visitation from other insects but not all pollinate.

Sedio describes the phylogenetic niche conservatism (PNC) phenomenon that occurs in plants.

In this phenomenon, a plant's microhabitat patterns are influenced by the biogeographical history of the plant's ancestors. He explains how related taxa are able to coexist since they were able to retain significant niche characteristics of their common ancestors.

The young leaves make large energy investments in chemical, developmental defenses, and floral nectar.

There were many variations among species suggesting that herbivory is a strong selective agent.

The research performed by Cavender-Bares and his colleagues highlights the importance of evolutionary processes combined with community interactions in community dynamics.

The combination of phylogeny with their functional attributes help in better understanding communities.

MacArthur and Levins explain that diversity of species living within the same environment can be explained as a result of limiting similarity.

Götzenberger's research suggest that species distribution is largely influenced by intraspecific competition (competition within the same species)

As the number of superior competitors increases, diversity decreases. This holds true only until other species are excluded.

Hartman's research focused on secondary metabolism in plants. These were associated with genes that have a high ability to change and adapt to the pressures of their environment.

Each plant population has unique secondary chemicals that have adapted to a plant's specific niche.

Swenson summarizes how to estimate the similarity between species by using both functional traits and phylogenetic trees.

He uses the data from these approaches to test the mechanistic community hypothesis.

Microsatellites, have been used by geneticists on plants in order to identify gene loci and how they can affect a certain trait or disease.

The research here describes the changes in genetics that have been triggered by environmental factors so that the palms can deal with salt and increased water amounts.

This taxonomic research was done in 1991 by Nauman and Sanders. Essentially it explained why there is genetic diversity amongst the Coccothrinax populations, and it is essentially because they come from three main groups each comprised of different traits.

This study yielded a Fst value, which essentially describes the degree to which a population interbreeds and how freely they do so. The current Fst value are very low compared to what was found in the experiment done in this paper. This is cause for further testing.

The research here was important because it identified the amount of Coccothrinax jimenezii that were present in the research sites. It also described patterns of palm distributions.

Given the great threat to the C. jimenezii, conservation efforts have been maximized.

See Dr. Bethany Radar and Dr. Ned Ruby use confocal images and immunocytochemistry to look at Vibrio fischeri in the crypts of the light organ:

A look at Vibrio fischeri

Bacteria in the light organ continue to grow and multiply. If the numbers get too high, the bacteria could potentially switch from being beneficial to being harmful.

Additionally, if bacteria develop mutations that cause them to stop producing luminescence, the mutants will use resources without providing benefit to the squid.

Consequently, the squid must have a way to control the number of bacteria that colonize the light organ. They do this by ejecting 75% or more of the bacteria in the light organ each day.

Work by Hargrave and McDowel (1992) and by Ridge et al. (2003) on phototransduction in the retina established that these three proteins are part of the G-protein-coupled pathway required in order for phototransduction to occur.

Chun et al. (2006) generated 11 cDNA libraries from the light organ of the bobtail squid.

Developmentally important time periods were chosen for analysis in order to provide a tool that would allow researchers to ask questions about how the bobtail squid responds to colonization by Vibrio fischeri.

Jones and Nishiguchi (2004) were the first to test the hypothesis that Hawaiian bobtail squid use bioluminescence for counterillumination (a strategy for camouflage). They measured changes in bacterial luminescence that matched changes in down-welling light (light coming from above).

Montgomery & McFall-Ngai (1992) and others discovered that proteins in the lens of the light organ of E. scolopes were similar to the proteins commonly found in the lenses of some mammal and cephalopod eyes.

The Euprymna scolopes-Vibrio fischeri symbiosis is a system with a single host and single symbiont, making it a great system to study how bacterial symbionts are acquired.

08-vid-clip02.mp4

The structures that control the amount of light emitted to produce counter-shading (PSVs) are different from the structures that produce the light.

Counter-shading refers to the fact that parts of animals that are exposed to light are usually lighter in color than those parts that are not exposed to light.

Loarie et al. found that spatial temperature gradients (degrees per distance) are larger for mountainous areas compared to flat areas. This means that, for the same change in temperature, a species that lives in a flat area must move much farther than one that lives in a mountainous area.

Therefore, the authors conclude that it should be easier for a species to keep up with climate change by changing elevation than by changing latitude, if distance is the only factor.

As the climate warms, plants and animals may need to shift their ranges to keep living in a suitable climate. Because temperature gradients vary in different types of ecosystems, we expect the size of range shifts to be variable, too.

For example, two regions experience the same increase in temperature over a period of 20 years. The temperature gradients are 1.3° per 100 km in the first region and 0.9° per 100 km in the second. Species in the first region will have to move farther to maintain their climate than those in the second region.

These studies show that increases in temperature are linked to changes in the life cycles of plants and animals. The dates of seasonal events, such as blooming, migrating, and egg laying, have changed for many species as their habitat has warmed.

The studies have demonstrated a statistical relationship between temperature and the timing of life cycle events: Larger changes in event timing occur in areas with greater temperature changes.

References 1-8 link biodiversity declines to climate change by showing that extinctions occur or are predicted to occur in areas where the climate has warmed.

This risk of biodiversity loss is a reason that the current meta-analysis is important: Quantifying how species ranges respond to climate change will help scientists and policymakers predict and hopefully prevent biodiversity loss in the future.

Climate is only one of many factors that determine the range of a species. These other factors may alter the way a species responds to climate change.

In the following sentence, the authors give examples of this.

Climate change can produce changes in extreme temperatures in addition to, or instead of, changes in average temperatures. A species that is sensitive to extreme high or extreme low temperatures may respond to these extremes rather than to the average.

Because extremes may change at a different rate from averages, these species may not appear to track climate change when it is measured by average temperatures (as in the current analysis).

Different species have different traits that may affect how quickly they can shift their range boundaries in response to changing temperatures. These traits include reproduction rates, ability to move, and ability to thrive in different habitats.

Researchers have documented that many species' ranges have shifted to higher latitudes and/or higher elevations during the same time period that the climate has warmed. However, they have not shown that the range shifts are statistically linked to the temperature change.

If species range shifts are directly linked to climate warming, we should find a positive trend between the two: the larger the temperature increase, the larger the range shift.

A meta-analysis, published in 2003, found range shifts in a large number of species, in directions consistent with climate change.

Large studies have shown that land-based populations of many living organisms have shifted to higher latitudes and/or elevations as the climate has warmed during the 20th century. These studies include plants and animals in many different locations around the world.

Polymerase chain reaction, or PCR, is a technique in the laboratory in which short sequences of DNA are amplified.

PCR has been used to detect DNA fragmentation on processed foods, where 18S rRNAs where the target for the experiment. Since they are small fragments, they work perfectly with the process since the goal is to amplify them to take a better look at them. The results of this experiment determined that the degree of DNA fragmentation are a great index for the chemical evaluation of various different foods.

The scanning and tail probing behavior of fish is the process in which they use certain tail movement around an object in order to discover the depth and size of objects in their environment. Think about what happens when you put a goldfish into bowl after it has been in an plastic bag. It will immediately start swimming around and swishing its tail around. That is a process of scanning and tail probing behavior.

What is critical to the success of active electrolocation is the knowledge of whether the electricity that is felt between the animal and the object is coming from the animal itself (reafference) or by the objects themselves sending the signal to these animals (exafference).

The complexity, speed, and variability of the electric organ discharge can be linked to the innervation patterns of the electric organ itself, which consists of thin nerve trunks and numerous branches of the electromotor axons leading towards the electric tissue.

Bennett's article analyzes the anatomy and physiology of the electric organs found within these electric fish. The membrane physiology of these electric organs evolved independently into six different groups and resulted in different membrane functions in different electrolytes which affect the electrorecption in the electric organism.

In some species of electric fish, there are sex-based differences between the EODs of males and those of females, all of which are regulated by steroid hormones. The primary hormones responsible for these variations in EOD are androgen (produces male-type EOD rates) and estrogen (produces female-type EOD rates). A notable example of a sex-based EOD difference is the male fish's ability to attract female fish with EODs that emit energy within the appropriate sensitivity ranges.

Only some data were published for site G. As a result, the data are less complete and less reliable. There are some differences in the measurements published by individuals viewing the original G tracks and those made by others using the fiberglass casts.

Large species sampling size necessary (or interspecific variation in species may be too high)

Warming experiments underpredict the advance of spring events

Experimental results alone cannot be used for parameterizing species distribution and ecosystem models

Best (currently) measure: observational data

Haber found that hawkmoths are frequent pollinators of these families, but require a significant nectar reward to do so.

Darrault and Schlindwein found these butterflies and moths do pollinate. Furthermore, in contrast to this study, they found that diameter of the mouth parts showed no correlation with pollen collected.

Inouye found that proboscis length was correlated with a bee's time spent at a flower. Waser found that many pollination systems tend towards specialization.

This implies that flowers adapt their shape and length to accomodate one group of pollinators. Length is a great determinant in these cases.

Lipow and Wyatt found in multiple studies that self pollination in this family of plants prevents fruit bearing. This can be problematic, as it can decrease seed output. As such, it could create pressure for plants to evolve to punish revisitors.

Instead of looking at how different environmental conditions, such as gaps, changed the migration of plants, research looked at how the variability in population growth of invading species affected their velocity of spread. Variability in population growth was seen to decrease the velocity of biological invasions. However, the decrease in velocity was small enough that it is largely negligible.

Due to the unpredictable nature of environmental events, studies of environmental changes, whether population, genetic or abiotic based, are forced to account for the randomness by repeating these experiments many times in order to ensure that the results are not due to chance, but have actual consistency.

Retrospective observational studies involve observing the result of a particular phenomenon, in this case an invasion, and collecting data to determine how it happened. While these studies can be effective at describing what evolution in invasions looks like, they are limited in the ability to determine cause and effect.

Populations that have been divided or separated from each other spread out slower than other populations but it is unknown how evolution contributes to their dispersal. The theory of natural selection dictates that offspring with traits that assist in dispersal and fecundity, or the number of offspring an organism produces, will be favored when populations are not very numerous and are in an environment well suited for their species' growth. Therefore, individuals best suited for the expansion of the population would be favored from an evolutionary perspective.

Natural and managed ecosystems are vital to the equilibrium of life on earth, as well as to humans needs which are gathered from ecosystems. The focus of the research question is to determine if biological invasions and movement of species are significant threats to ecosystem health.

Scientists characterized rat USVs and demonstrated that some (22 kHz) are associated with negative reactions and others (50 kHZ) are associated with positive reactions to their environment.

"Valence" is a psychological way of categorizing an emotional state as good (positive) or bad (negative).

Subalpine bee species have begun to move into alpine climate and compete with the native alpine bees, due to the warming of the alpine climate.

Alpine bumble bee populations are generally isolated from the toxins, diseases, and habitat destruction that affect bumble bee populations in other climates. Yet, they are still negatively affected by climate change. However, the bumble bee populations are adapting to the changes to their habitat by evolving new behaviors that increase their chance of survival.

Researchers have found that climate change has increased the temperatures of alpine and arctic habitats. This has caused the soil in this area to dry up thereby decreasing the amount of plants that flower in a given area, negatively affecting the bees ability to forage.

Rodríguez-Gironés and colleagues saw that competition for resources within a population triggered long tongues in pollinators and deep corolla tubes in flowers.

Researchers have identified potential reasons that could be causing the decrease in long-tongued bees including changes in the location and availability of flowers, habitat destruction, and the presence of invasive species.

Historically, bees with longer tongues have had access to plants with longer corolla tube lengths, increasing selection for these bees that have a wider range of accessible nutrients. Researchers believe, due to a decrease in the population of long-tongued bees, that the long-standing selective pressures that caused long-tongued bees to thrive are changing. The reasons for this change remain unknown.

fMRI was used to detect brain activity in healthy volunteers who were being tickled. The somatosensory cortex was one region that was activated by tickling.

When patients were asked to tickle themselves, there was also activity in the cerebellum, a region of the brain associated with coordinating movement. The researches suggest that the cerebellum may have a role in detecting self-tickling and suppressing the tickle response.

This idea may have been originally proposed by Charles Darwin. He wrote that if a child is tickled by a stranger, the child would scream from fear rather than laugh.

Traditionally, paleobiologists hypothesized that early hominids exhibited a high degree of sexual dimorphism. This thinking is based on limited fossil evidence and consequently is being questioned by a number of researchers.

The Global Biodiversity Information Facility provides an open online database of biodiversity data. This service was vital for the outcomes of this paper as it was a source for determining species ranges. The occurrence records used show the location of a given species and the date they were located.

A previous experiment determined how biodiversity, nitrogen deposition, and CO2 affected grassland soil carbon cycling. The results were vital for this research in that they provided guidelines for the what data should be provided. Specifically, this refers to providing higher and lower amounts of economic change than would be expected in order to provide a range of possible values.

BioCON stands for Biodiversity, CO2, and Nitrogen. It refers to an experiment which began in 1997 at the University of Minnesota. The factors of this experiment can be related to the economic value of ecosystems, it is vital in the outcomes of the research done in this paper. Without the values from the BioCON experiment many of the results in this paper would not exist.

In a previous work produced by R. A. Gill and coworkers, the carbon contained in a plants' root system was calculated (.55 per year). This is also the average value for roots to seep carbon into the soil in grasslands.

The BigBio experiment was conducted to examine large scale biodiversity in a grassland setting. The experiment determines effects of plant species numbers and functional traits on the functioning of an ecosystem. Without previous data obtained from this experiment, many values found in this research wouldn't have been able to exist. Therefor the BioCon experiment was vital to the outcomes of this paper.

Multiple research studies, conducted by leading scientists P. Balvanera, S. Catovsky, and I. D. Thompson, suggest that the economical worth of plant diversity is high for all ecosystem services. The author points out that the research conducted on the correlation between species richness and specific ecosystem services is very rare.

A research study, drafted by J. E. K. Byrnes and others, states the importance of studying the effect of increased plant diversity on a wide variety of ecosystem processes. This research paper only shares the results of increased species richness on one ecosystem service: carbon storage. There are many more ecosystem services that are only possible because of the wide diversity of plant life on earth. If research studies were conducted on the effect of increased plant diversity on a variety of ecosystem services, then we would gain irreparable knowledge on how the complex systems work and the benefits to society.

A research paper, written by J. S. Lefcheck and coworkers, proposes that no single species is the best at providing all the valuable ecosystem services needed for the world to function. No single species can occupy all the vital niches around the world. This is why diversity between the function plant species have and services they preform is so important.

A previous research experiment, conducted by E. S. Zavaleta and coworkers, concludes that there is evidence of differences between the function plant species preform and the services they provide. The differences between plant species allows for a wide variety of niches or jobs, in an environment, to be filled. Without different plants occupying the many needed jobs in an environment, the earth's delicate nutrient cycles would not be able to occur and life on earth, for primary and secondary consumers, might not be possible.

A previous research study, written by P. B. Reich and others, voices that the initial introduction of increased species richness drastically increases carbon storage, but as time goes on, the effectiveness of plant diversity on carbon uptake starts to level off. The author relates these findings to their own experiment stating that even though the research conducted on the American grasslands is the longest-running biodiversity experiments in grasslands, not enough time has passed to see carbon storage levels reach a steady state.

In a research study, conducted by D. A. Fornara and other scientists, C4 grasses and legumes were found to promote the greatest amount of carbon accumulation in the soil. If these two plant species were to go extinct, the total amount of carbon storage would vastly decrease because they are the main contributors to carbon accumulation in the soil. The results of this previous research study support the conclusion that different plant species affect ecosystem services differently.

A research paper, drafted by C. M. Tobner and others, states that specific characteristics of different plant species influences ecosystem service such as: climate regulations, the amount of atmospheric CO2 converted into biomass (carbon storage), and water purification. All plant species do not affect atmospheric CO2 reduction in the same capacity. The loss of certain plant species could have a greater impact on ecosystem services, like carbon storage, than others plant types.

A previous research paper, written by B. J. Cardinale and others, showed that there may be a general relationship, in all environments, that increased plant diversity increases the amount of carbon storage. Different environments around the world could respond differently to the same level of species richness, but will have an overall increase in carbon uptake.

The author suggests that the estimated values of the most effective amount of plant diversity, for different environments, could show variation in the relationship between species richness and carbon uptake. By conducting experiments, on a variety of different environments, we will be able to figure out the best level of plant diversity, in specific environments, for the highest level of carbon storage. These results could greatly help reduce the CO2 pollution in the atmosphere and help deter global warming.

A research study, by K. Paustain and others, indicates that the increased uses of forest species, in stripped farmlands, rather than using grassland species could help advance the knowledge of what is the best way to benefit the human population. This gain of knowledge, about land management, would help find the most effective way to decrease the amount of CO2 pollution in the earth's atmosphere. At the very least, the increased awareness of different methods of restoration, for different land types, would determine the additional increase in carbon uptake and its economic worth to total carbon reduction.

In multiple research papers dictated, by leading scientists A. Paquette and L. Gamfeldt, that higher species diversity in forests correlates to increased carbon storage. This research gives insight into the possibility of using forest species, for restoration purposes, instead of grassland species to increase the total amount of carbon storage in a environment.

A previous research study, conducted by C. Fissore and coworkers, proposed that increasing species richness in recently abandoned farmlands, with low levels of carbon in the soil, to become diverse prairies would result in a higher increase of carbon uptake when compared to increasing plant diversity from 6 to 7 in CRP grasslands. Meaning that the addition of species richness, in environments with low levels of carbon, has a greater affect on carbon storage than conservation grasslands. By turning recently abandoned farmlands into diverse prairies, through the introduction of plant diversity, the amount of carbon sequestered from the atmosphere increases and helps deter global warming faster than the use of CRP grasslands.

In a previous work written by P. Torok and research team, concluded that the use of a diverse seed mixture is more expensive to farmers than growing only only type of seed. This is a drawback to the the benefit of increased species richness in farmlands, but the advantage of a diverse array of plant species far out weights the initial cost when considering carbon uptake in an environment.

A previous research paper posted, by leading scientists E. Grman and D. L. Larson, reported that the practice of increasing plant diversity is simple. All farmers have to do is use a seed mixture with a more diverse array of plant species. The use of the diverse seed mixture will help increase the carbon uptake in the farmers fields and help decrease atmospheric CO2 levels.

In a previous Minnesota grassland experiment, the addition of species richness from 6 to 7, increased the carbon uptake, of the CRP grasslands, by about $722 million. The increase of species richness from 6 to 11 increased the total carbon uptake, of CRP grasslands, by $2.350 billion. The authors used the economic worth or carbon to calculate the numbers seen above. Overall the author is trying to convey that increased species richness, in CRP grasslands, vastly increases the amount of carbon sequestered by the plants and is a huge benefit to carbon reduction in the United States.

J. L. O'Connell and coworkers published estimates of plant diversity in CRP grasslands compared to native grasslands. The author of this research paper found similar results that species richness in CRP grasslands was lower than the native grasslands.The lower recorded plant diversity means there is a higher potential, in conservation grasslands, for increased species richness and ecological benefit.The increased plant diversity, in CRP grasslands, will benefit the ecosystem by increased uptake of carbon from the atmosphere and contributions to nutrient cycles.

The author of this research paper used the findings of K. Paustain and coworkers to estimate the carbon uptake of CRP grasslands over 12.34 million hectares. The conversion of previous farmlands to grasslands helps increase the amount of carbon taken from the atmosphere by 6.54 teragrams per year. This helps reduce the total pollution of CO2 in the earth's atmosphere and restore nutrients to the deprived farmlands.

The previous research (26) states that species richness is not uniform throughout an ecosystem since the amount of species throughout an ecosystem can vary due to different conditions.

The paper also points out that other conditions besides carbon storage can affect biodiversity of an ecosystem. This paper takes that into consideration by comparing the results of the experiment to the historical levels of biodiversity recorded in the grasslands.

The establishment of the Conservation Reserve Program was important in determining the results of this experiment. The program was created to encourage farmers to use some land to plant vegetative cover rather than crops to provide habitat for pollinators, reduce erosion, and improve water quality.

The federal government pays farmers to make these land conversions, which places an economic value on species richness.

A previous research paper, drafted by J. P. Reid and others, suggests that increased plant diversity, in a grassland environment, shows evidence of stimulating carbon turnover in the soil. The greater the number of plant species, the faster carbon cycles through the environment.

The cycle is as follows: atmosphere -> plant (via photosynthesis) -> soil -> back to plant -> back to atmosphere due to plant respiration.

A research paper, composed by J.H. Goldstein and others, states that the price of carbon emissions (provided by the carbon market) influences the amount of land companies are allowed to obtain. If companies have a high rate of carbon emissions going into the the earth's atmosphere then the amount of land they can use decreases.

In multiple research papers biodiversity was calculated using a number, rather then a qualitative assessment. This paper takes the same approach. Diversity is thus assigned a number instead of an observation for further calculations to determine the affects of biodiversity on carbon storage.

In a previous research paper, written by D. A. Fornara and coworkers, it was described that as species diversity declines carbon gain is reduced and in long-term experiments the decline of species richness reduced the total amount of carbon in the soil. Meaning that as plant diversity decreases the amount of carbon taken up by plants decreases and in the long-term the amount of carbon stored in the soil also decreases. If the amount of carbon in the soil decreases that means that there is more carbon being stored in the atmosphere, which proves that plant species diversity is vital for climate regulation.

In multiple research studies conducted by leading scientists, A. Paquette, L. Gamfeldt, and J. Liang, proposed that local species richness contributes to carbon gain across a variety of different climate and soil conditions. Meaning that plant diversity in an ecosystem, regardless of climate and soil conditions, causes an increase in carbon uptake by plants. Which can be seen through the increased growth of plants in an environment.

A previous research paper, by B. J. Cardinale and others, states that a decrease in species richness causes a decrease in biomass accumulation. This shows that carbon sequestration diminishes as ecosystem biodiversity decreases. This is driven by less competition among species which in turn increases carbon availability and decreases total carbon uptake.

Has the Earth's sixth mass extinction already arrived? A. D. Barnosky, N. Matzke, S. Tomiya, G. O. U. Wogan, B. Swartz, T. B. Quental, C. Marshall, J. L. McGuire, E. L. Lindsey, K. C. Maguire, B. Mersey, E. A. Ferrer

This article suggests that the current rate of species extinction is higher than what has been expected in the past (compared against fossil records). The authors propose that this elevated rate of extinction may possibly be the beginning of the 6th known mass extinction event on earth.

This extinction would drastically lower biodiversity by killing off many species that would otherwise function as carbon sinks. The release of such massive amounts of carbon might have dramatic effects upon the environment.

A previous research paper, written by Keystone Center, states that genetic diversity in the plant life along with the way communities of plants interact in an ecosystem is vital for the carbon storage cycle on earth. Different species of plants are able to store different amount of carbon, if there was no diversity between plant species then the amount of carbon storage in an ecosystem would be altered. Without diversity in plant species, our oxygen-dependent existence and regulation of global climate might not be possible.

Past and present of sediment and carbon biogeochemical cycling models

By: Mackenzie, FT (Mackenzie, FT); Lerman, A (Lerman, A); Andersson, AJ (Andersson, AJ)

This is a secondary study of the history of the carbon cycle, with respect to the onset of industrialization as well as the dynamic role the ocean plays in carbon storage. Prior to industrialization, the ocean was a net source of CO2 emissions due to the net carbon differences between photosynthesis and respiration. However, the massive CO2 releases from the burning of fossil fuels have made the ocean into a net carbon sink.

This citation is referring to the storage of carbon within calcium carbonate (CaCO3), or limescale within the ocean. This limescale comprises most of the 'rocks' in reference.

Typically, insulin is obtained from the food we eat, if the mosquito does not have enough nutrition and food the insulin levels will be low. If the mosquito's nutrition improves than the insulin will be obtained from the food she eats.

When insulin or the juvenile hormone binds to a receptor it carries out a process so it can send a message to the nucleus of the cell, this allows for activation of regulation. When insulin binds to the insulin receptor that stimulates development and growth. In this case, the juvenile hormone regulates metabolism, reproduction, and nutrition within the cells of mosquitoes. This way insulin and the juvenile hormone are working together in keeping the insects healthy.

Longer fish would be affected by limits in their water environment more than smaller fish because their length and greater ability to swim faster makes them more likely to have cavitation occur in their bodies. The increase of cavitation bubbles in their bodies would injure them and ultimately lead to their death.

The researchers tried to understand more about the maximum speeds of these fishes but unfortunately the technique of videotaping the fish in action were not able to provide enough information because they could never catch the fish swimming at their true maximum speed.

In reality, even if you could see a fish swimming at its maximum speed, what that speed is would differ based on the environment of the fish. One variable in a fish's environment that affects its speed is the strength of the water current. If the current is great, then a fish swimming against it at its maximum ability would have a lower tail-beat frequency compared to the same fish swimming at its maximum ability in the direction of the current. You can think of how water current affects underwater organisms the same way how strong winds affect land organisms.

Recent studies have shown that billfishes often prefer slower, more accurate swimming rather than fast swimming. This is said to be preferred due to their prey's maneuverability which is achieved by swimming unsteadily. Unsteady swimming refers to the sharp turns and quick changes in acceleration that smaller fish often use to escape larger predators.

The speed an animal can achieve when chasing prey is one factor that determines what type of prey they can or cannot eat. In terms of this, the more different types of speeds a fish can achieve, the more varieties of smaller fish it can successfully chase and eat. For the fishes studied, none of them swim at their maximum speed because it is not required to swim that fast to consume their prey.

Background information on Wolbachia colonization mechanisms in germ line cells is not well known. Concentration variation may be due to multiple factors.

Wolbachia enter several different types of cells with the ultimate goal of infecting eggs and passing on to the next generation.

Wolbachia ensures maternal transmission by leading to the death of eggs fertilized by infected male flies. This does not occur, however, when an infected female and her eggs mate with an infected male fly. Wolbachia modify sperm in infected male flies, but do not reside within the sperm.

wMelPop Wolbachia variant is unique in being more pathogenic than symbiotic (as with most other strains of Wolbachia). It is not harmful to developing flies, but divides quite vigorously in adult flies, damaging several tissues, and ultimately prematurely killing the adult fly.

Wolbachia is known to confer resistance to viruses in hosts it infects.

Wolbachia have been found to be essential for proper production of offspring by certain organisms.

Hosokawa et al. found that Wolbachia bacteria are essential for proper development of the bedbug, Cimex lectularius, through provisioning of vitamin B, an essential cofactor. Cofactors ensure that enzymes function correctly.

Genus Wolbachia is quite diverse.

It was found that about 52% of all insect species are infected with Wolbachia endosymbiotic bacteria.

Wolbachia are found in various nematodes (e.g. roundworm) and arthropods (e.g. insect, spider, crustacean).

Although a symbiont is typically understood to be helpful for the host organism, the line between endosymbionts and parasites is not well delineated. This is especially the case, for example with Wolbachia. This bacterium is capable of ensuring its transmission by favoring the survival of fly egg cells that are infected, and leads to the death of uninfected fly eggs. On the other hand, Wolbachia is also known for making infected fruit flies resistant to certain viruses that would otherwise afflict the flies.

The author is stating that when Rokas et al. carried out the experiment to record bootstrap values in randomly sampled and contiguous gene sequences, the methods used to test variance were flawed. Rokas used two different techniques to test bootstrap value variance for randomly sampled and for gene sequences. The use of a different method when testing the randomly sampled sequences resulted in bootstrap values with very little variance, Rokas' conclusions were no longer considered reliable.

In this previous study, the authors had come to the inaccurate conclusion that single genes provide misleading phylogenetic signals because the results they gave varied widely when compared to random genes and also had low confidence levels.

One of the biggest problems in the field of phylogenetics is the incompatibility of data that is obtained when single genes are used. In order to solve the problem of incompatibility, Rockas used "106 widely distributed orthologous genes for phylogenetic analyses, singly and by concatenation." The results that were given by this experiment showed that a chain of genes delivered a fully resolved "specie tree" with support. This was also seen by using a small quantity of 20 genes.This is extremely important as it can be a revealing answer and a way to figure out the different branches of the tree of life.

In this study, scientists were able to conclude that under certain circumstances (when processes are stationary over lineages and time) short genetic sequences can be used to construct a large phylogenetic tree with very high accuracy, therefore reducing the cost and time spent in creating a tree.

Scientist were able to conclude how stationary genes evolve through the same velocity at the third codon position. In comparison, non-stationary genes were seen to be involved in severely higher conditions. Such differences could therefore lead to drastic results, including systematic error.

Rokas et. al came to the conclusion that one needs a minimum of 20 genes in order to compose an accurate phylogenetic tree, and that those phylogenies created from examination of a few genes are unreliable due to the low amount of sequencing data used.

The goal of (14,15) was to help build a "Gold Standard Report" (GSR) reliable database of civil unrest events across countries in Latin America.

Utilizing DEET perfumed traps, the behavior of flies was observed. Flies with the Orco gene responded differently to food-baited traps than flies with the gene knocked out. Low concentrations of DEET cannot repel flies in the absence of food. Electrophysiological studies showed that DEET can influence signaling molecules (or ligands) and their respective olfactory receptors.

Three taste receptor neurons were characterized in female Aedes aegypti mosquitoes. The neuron with the smallest amplitude spike responded to the feeding deterrent, quinine, and other insect repellents. Two other neurons with differing spikes responded to salt and sucrose. This was the first report of a taste receptor neuron specific for insect repellents in mosquitoes.

Female Aedes aegypti mosquitoes fed through a membrane on citrated blood containing DEET. When 0.5% concentration of DEET was present in the blood, the mosquitoes barely touched the membrane and did not insert the proboscis into the blood. When the concentration was lowered to 0.065%, mosquitoes touched the membrane for a longer time period, and/or inserted the proboscis. It was concluded that vapor action was the main cause of repellency, but contact chemoreceptors on the lobes of the proboscis may have been involved during the 0.065% concentration experiment.

This article has been retracted as of 2016 by the request of all authors except Pinky Kain. The authors identified background effects that were originally missed and, as a result, do not have confidence in the data supporting that Ir40a is a DEET receptor. The authors remain confident of the analyses used to identify new repellents which have been replicated in the laboratory.

The CquiIR40a receptor in the Culex quinquefasciatus mosquito was cloned and then expressed in the Xenopus ovary cell along with another co-receptor. The Culex quinquefasciatus mosquito uses an odorant receptor, CquiOR136, to detect insect repellents, such as DEET, picaridin, IR3535, and PMD. The dose-dependent responses elicited by these repellents were analyzed.

When applied to human skin, DEET altered the chemical product by a fixative effect, which may have contributed to repellency. The electrophysiological responses of olfactory receptor neurons (ORNs) were observed in Culex quinquefasciatus mosquitoes. The same ORN responded with higher sensitivity to terpenoid compounds, which are found in essential oils. The studies support the smell and avoid hypothesis.

As the stimulus intensity increases, the firing rate of neurons increases. The firing rate is the rate of action potentials that carry an electrical impulse down a nerve. DEET increased the firing rate of olfactory receptor neurons in A2 sensilla, but inhibited the firing rate in A3 and A4 sensilla. It was concluded that DEET plays multiple roles in olfaction control because it affected OR-expressing and IR-expressing neurons in differing ways. This supports the confusant hypothesis.

Mosquitoes use redundant mechanisms to sense their hosts. This mechanism requires that mosquitoes receive multiple cues for a host to seem attractive. The disruption of one pathway is unlikely to eliminate mosquito host-seeking, however. Stimulating multiple sensory pathways may increase the chance of a mosquito successfully targeting a host.

Zinc-finger nucleases (ZFNs) were used to generate mutations in the Orco gene of Aedes aegypti. ZFNs are a class of engineered DNA-binding proteins that facilitate targeted editing of the genome by creating double-strand breaks in DNA. These breaks stimulate the cell’s DNA repair processes, which in turn generates precisely targeted genomic edits.

DEET was concluded to be a compound that reduced the attraction of mosquitoes to lactic acid (a behavioral inhibitor) rather than a compound that caused mosquitoes to display complete avoidance. It is important to note that both DEET and lactic acid were attractive to mosquitoes in the studies.

Studies that observed heart rhythms were used to observe the sensitivity of olfactory sensory neurons (ORs). DEET reduces the sensitivity of ORs by enhancing the expression of lactic acid-inhibited neurons and decreasing the expression of lactic acid-excited neurons. This supports the inhibition hypothesis of host odor detection.

The Aedes aegypti mosquitoes aided in the discovery of DEET, which is the most common active ingredient in insect repellents. The behavior of the mosquitoes was observed in response to several compounds, but N,N - diethylbenzamide was found to be the most effective. Because this compound is irritating to the skin, the DEET found in repellents today is comprised of derivatives of N,N - diethylbenzamide.

Prior work from author Guiot developed a reconstruction of the Mediterranean region's climate over the past 10,000 years. The reconstruction used the BIOME4 model, with pollen core data as the input. The reconstruction found that the past climate variations were dominated by changes in precipitation (droughts and wet periods). However, unlike in the present, the drought periods were linked to cool temperatures. They also found that the pattern of warming was different in the past than it is currently.

Using this information, they concluded that the reconstruction indicates that recent warming in the region is unlike what was seen during any other time in the Holocene.

BIOME4 was developed by Kaplan and colleagues. The model uses input data about water, climate, and soil to simulate the ecosystem and plant processes that drive the distribution of vegetation types. Using this information, the model identifies key variables and uses these to rank the likelihood of different groupings of plants for the given time and location. The rankings then help identify the biome type present.

This model predicts plant distribution based on underlying processes that are expected to be consistent for the entire Holocene time period–for example, net assimilation of CO₂ (the flux of CO₂ between a leaf and the atmosphere) or the water balance in an ecosystem. The authors contrast that method to other models that are tuned based on how well the results correlate with, or reproduce, current vegetation patterns.

Kelly and colleagues examined the 3-year drought in Syria that began in Winter 2006/2007 to understand what contributed to the severity of the drought, which was the worst in human record.

The researchers found that though multiyear droughts do occur naturally in the region, the reduced precipitation and increased surface temperature of the past century that is consistent with models of human-driven climate impacts contributed to the extreme nature of the drought.

The impacts of the drought were also amplified by previous droughts, the reduction of groundwater supply (which had previously acted as a buffer), and population increases in recent years.

The current period is experiencing both reduced precipitation and high temperatures, unlike during the earlier Holocene, when times of low precipitation were generally cooler.

Precipitation and temperatures vary across the Mediterranean region, and the precipitation patterns are more variable than the temperature patterns. In general, the changes of these two climate variables in the next few decades are expected to lead to a reduction in the amount of water available as well as the loss of some ecosystems and biodiversity.

Guilot, one of the authors of the current paper, and his collaborator used pollen core data and vegetation modeling to develop reconstructions of the Mediterranean Basin climate over the past 10,000 years. To do this, they ran BIOME4, a vegetation model, in "inverse" mode.

BIOME4 is typically used to predict vegetation by inputting climate information. In an "inverse" mode, researchers input the vegetation information from the pollen cores and then used a computer algorithm to calculate what climate would have produced the mix of plants that was observed.

This reconstruction method is the basis of the current paper.

The targets are for global temperatures, based on averages across the entire surface of the planet. Because of climate variations, this does not mean that each location would experience the same degree of local climate impacts.

For example, researchers examined the impact of the global 2°C increase scenario on regional changes to temperature extremes and their analysis found regions that would have a bigger response. For the Mediterranean region, they predicted a 3°C increase in hot temperature extremes.

Previous models have tried to explain the apparent lack of homology by suggesting that anatomical placodes and dermal papillae developed at least twice (once in birds and once in mammals).

Further, the models suggest that, although the anatomical placodes and dermal papillae in mammals and birds would have evolved independently, they would have came about through the co-option of the same set of signaling pathways.

Crocodilian scales are formed through exertion of force: Scale tissues are physically cracked by living materials, leading to unique patterns on each reptile's face.

Some other models reject the idea that the placode and the dermal papilla evolved independently, suggesting that the similarities in the molecular signaling involved in development are sufficient to show that they are homologous (meaning the pathway evolved once, in a common ancestor).

It is also suggested that this is true for turtles, which have been found to need the placode for the development of their shell.

As was found in previous studies, scale development begins with the formation of risen areas on the skin. The symmetry and degree of overlap of the final scales depends on the species and location on the body.

Other authors have estimated similar amounts of waste generated by humans.

In chickens, feathers develop in 10 distinct areas (tracts) which correspond to different parts of the body. These tracts develop at different rates and have their own patterning.

People who are used to low-altitude environment experience several health complications, sometimes even fatal ones. Low levels of oxygen at high-altitude environment also decrease reproductive rates. One common disease seen in people that live in high-altitude environment is Monge's disease. Monge's disease is characterized by overproduction of red blood cells. Interestingly, Tibetan highland population is resistant to Monge's disease because of the decreased level of hemoglobin concentration.

EGLN1 and PPARA are correlated with hemoglobin concentration. EGLN1 encodes PHD2, prolyl hydroxylase domain-containing protein 2, which is a negative regulator of HIF-1α. PPARA encodes for PPARα, peroxisome proliferator activated receptor alpha. PPARα is regulated by HIF protein, and is essential for fatty acid metabolism. Since PPARA induces fat metabolism, it is unfavorable in hypoxic conditions because fatty acid metabolism needs more oxygen for energy production compared to glycolysis. PPARA is therefore negatively correlated with the concentration of HIF-1α. The positive selection seen in EGLN1 and PPARA, which are negatively correlated with the concentration of hemoglobin, indicates that Tibetans have a unique adaptation.