mscheller's blog

All different kinds of birds from sparrows to hawks form flocks. They can number in the single digits or be composed of thousands of individual birds seemingly acting like one cohesive organism. The main benefit gained from flocking, especially for small birds, is safety in numbers. Although overall a flock is much more conspicuous and easily targeted by predators than a solitary bird, for the individual the likelihood of becoming a victim is greatly decreased due to the higher availability of targets to choose from. A flock also benefits by being much more vigilant than an individual could be and is able to recognize threats much sooner and alert the other to flee the danger, overall increasing all birds likelihood of survival from predation. 

The Saiga antelope of the Eurasian steppe is perhaps one of the strangest looking ungulates on the planet. Characterized by very distinct bulbous downward facing nostrils along with long pointed horns, the saiga looks like a cross between an elephant and a regular antelope. Unfortunately, as of February 2018, this weird but beautiful mammal remains critically engendered and continues to decline in population. Saiga face an unfortunate gauntlet of factors that are leading to its rapid decline, but arguably the most impactful has been habitat loss due to human agricultural development and climate change coupled with illegal hunting. Recent efforts in Russia and other countries within the saiga's range have decreased poaching rates but climate change and human encroachment continue to decrease available feeding grounds. The rate of decline of this species rivals that of any other animal in terms of the size and speed at which the population fell. In the 1980s there were over a million Saiga on the Eurasian steppe, but in just 30-40 years that number has fallen to under 50,000 with an estimate of the population of S. t. mongolica, a subspecies found only in the Mongolian high plains, being under 750 mature adults worldwide.

The Saiga antelope of the Eurasian steppe is perhaps one of the strangest looking ungulates on the planet. Its very distinct bulbous downward facing nostrils along with its long pointed horns almost give it the look of some strange deer/elephant hybrid. Unfortunately, as of February 2018, this weird but beautiful mammal remains critically engendered and continues to decline in population. Saiga face an unfortunate gauntlet of factors that are leading to its rapid decline, but arguably the most impactful has been habitat loss due to human agricultural development and climate change coupled with illegal hunting. The decline of this species rivals that of any other animal in terms of the size and speed at which the population fell. In the 1980s there were over a million Saiga on the Eurasian steppe, but in just 30-40 years that number has fallen to under 50,000 with an estimate of the population of S. t. mongolica being under 750 mature adults worldwide.

Everyone knows birds migrate, but the root cause behind this migratory behaviour can fall into one of two categories. Obligate migration is what one usually thinks of when it comes to bird migration; the seasonal flights made between predictable breeding and non-breeding grounds at specific times of the year that seem to be hard-wired into the birds that follow this behavioural pattern. The other form of migration called facultative migration happens at unpredictable times of the year and is in response to a change in resource availability or an environmental shift. These migrations are not associated with mating and happen seemingly randomly and do not have a set destination. There are situational advantages and disadvantages to both of these forms of migration and they have evolved separately multiple times across all orders of birds. 

Proteins like the Green Fluorescent Protein first isolated from a jellyfish fluoresce when excited by certain wavelengths of light. Fluorescence is different from luminescence or incandescence in that these two light-producing reactions use chemical energy and heat as their respective energy sources for the production of light. Fluorescence is the process of generating light when light is also used as the energy source to power the reaction. This is accomplished through a mechanism called the photoelectric effect in which the absorption of a photon of light causes an electron to jump to a higher energy state. As the photon returns to its ground state, energy is given off in the form of light at a lower energy level than that which was input into the system. 

Like many genetic disorders, the mechanism that leads to the symptoms associated with different forms of muscular dystrophy is some level of dysfunction within a protein caused by a mutation in the gene that encodes for the associated protein. In the case of muscular dystrophy, the protein culprit is a structural muscle protein called dystrophin. Individuals afflicted with muscular dystrophy do not properly translate this protein and its absence leads to muscle necrosis through young adulthood in boys, almost always leading to a life expectancy below 30. There have been hundreds of confirmed mutations that lead to one of nine varieties of MD, and 1/3 of cases come from novel mutations that were previously unknown. This makes it an especially difficult disease to treat from a gene therapy standpoint as nailing down the precise genetic origin of the disease takes time and once isolated, a specialized approach is required to target each patient's individual case leading to an even larger time and financial investment. 

The genetics of dog hair colour is much more complicated than most people might think. There are many different genes, each themselves with sometimes three or four alleles, whose combination leads to the hundreds if not thousands of different coat varieties seen in canids both domestic and wild. Many people tend to think of genetics as working in the traditional Mendelian fashion of basic dominance and recessiveness of genes controlled by a single allele (say A/a), but dog hair colour is one of many examples where the answer is not that simple. The introduction of more than two alleles whose dominance over one another varies leads to many more possible combinations of traits and is why the pattern, colour, length and curliness of dog hair varies so widely across the family Canidae. One gene that plays a key role in coat colour is the agouti gene that encodes for a signalling molecule which disrupts the pathway in fur melanocytes (specialized pigment-producing cells) that leads to eumelanin production, these being darker brown and black pigment molecules. As a result, dogs that express the aguoti gene at high levels instead produce lighter phaeomelanin pigments that result in yellow, gold and even red coat colours. It's still not that simple however because the agouti gene has four alleles (a, a^w ,a^t , a^y ) each leading to varying levels of expression and different patterns of light and dark colours seen across the Canidae family.

Speciation is the process by which one lineage splits into two separate species as a result of selective pressures as well as due to evolution by natural selection. This process can occur under two broad categories of allopatric or sympatric, each leading to the outcome of speciation through two distinct mechanisms. Allopatric speciation occurs as a result of the geographic splitting of one species traditional range whether it be by a river, mountain range, canyon or human development like highways and canals. Sympatric speciation occurs when two different species arise within the same habitat with no geographical separation between the two. This process can occur as a result of the presence of an unfulfilled ecological niche which once filled leads to a split in the behaviour and breeding habits within one species, eventually leading to two new species through genetic isolation of the two populations. 

The genetics of dog hair colour is much more complicated than most people might think. There are many different genes, each themselves with sometimes three or four alleles, whose combination leads to the hundreds if not thousands of different coat varieties seen in canids both domestic and wild. Many people tend to think of genetics as working in the traditional Mendelian fashion of basic dominance and recessiveness of genes but dog hair colour is one of just many examples where the answer is not that simple. The introduction of more than two alleles whose dominance over one another varies leads to many more possible combinations of traits and is why the pattern, colour, length and curliness of dog hair varies so widely across the family Canidae.