Avian Song Control
Bird songs continue to fascinate neurobiologists and neuroethologists because the development of song has been a popular model used to examine the role of environment on behavior. In most species, only male birds sing complex songs. Their vocalizations are the result of sexual dimorphism in the brain regions responsible for the production of song. However, this behavior is not genetically hardwired into the avian brain. Certain conditions must exist in order for male birds to successfully produce their species-specific song. Additionally, the neuronal circuitry and structure of the avian song system shows high levels of plasticity.
If the brain and behavior are indistinguishable, then the structural differences in the avian brain are responsible for behavioral differences across the sexes. Nottebohm and colleagues identified six anatomically distinct regions of the forebrain involved in the production of song, which are arranged into two independent pathways, the posterior pathway, which controls song production, and the anterior pathway, which controls song learning. The collective unit is typically referred to as the vocal control region (VCR) (1) (2).
Female birds sing rarely and this behavioral difference is reflective of the anatomy of the female avian brain. There are significant differences in the size of three neural areas involved in the production of song across the sexes, and a specific area, Area X, is present in the male and absent in the female. Additionally, the incorporation of radiolabeled testosterone in certain locations is different in males and females (3) (4).
Scientists have been particularly interested in the origin of the structural differences in male and female songbirds. Research has suggested the importance of gonadal hormones, specifically testosterone in the production of song. It was observed that castration eliminated all song production (5). Additionally, when testosterone levels are low, there is not only a decrease in the production of song, but also a decrease in the size of some nuclei involved in song production (6). Further support for the necessity of testosterone for song production was demonstrated by Nottebohm (1980) when he injected female birds with testosterone, which lead to the production of song (7). This research has interesting implications regarding anatomical changes that may occur when an organism is chemically imbalanced. Disruptions in chemical equilibrium may alter brain structure and subsequently influence behavior.
Nevertheless, not all research has supported the claim that testosterone is responsible for anatomical and behavioral differences between male and female songbirds.
A male ruby-throated hummingbird has a brilliant, fiery red throat, kaleidoscope green back, forked tail with a gray and white underside. The females don’t have such flashy colors, lacking the red throat and their tails are blunt, w...
...sues causing an increase in the popularity and intensity of youth gang activity in targeted neighborhoods. This program has taken a bold, integrative approach to dealing with the issue of increasing membership and participation with gangs. The research findings for this program have supported the notion of its success and make assumptions about its continued success in the future. The program has shown to be of great value to those in the program and should continue to receive support and funding from government agencies and community members.
Criminal activities and gangs have mostly always been an on going problem in the United States. Gangs and gang members are frequently involved with a variety of different crimes. The 2008 National Youth Gang Survey reported that there are approximately 774,000 active gang members in the United States (Egley, Howell, & Moore, 2010). The 2008 National Youth Gang Survey also states that there are about 27,900 active gangs in the United States (Egley et al., 2010). The active gangs in California have caused a major impact on the state in many ways. According to the California Department of Justice, approximately 300,000 gang members are living in California (Crawford, 2009). California also attributes more than 25 percent of all homicides to gang activity (Crawford, 2009). This is a staggering huge amount. The rise of gang involvement and gang crime has led law enforcement to issue and enforce gang injunctions. However, these gang injunctions do not completely eliminate gang crime and they have no effect after one year of being issued. Also, gang injunctions interfere with the lives of normal people in society.
High educated and talented people is the fundamental for the economic development in the cities. In Detroit, many workers in the car industries are either unskilled or low skilled workers with only high school diplomas simply because of those works do not need special talents or skills in order to have the work done. Due to the division of labor, large jobs are breaking down into many tiny components. “Under this regime each worker becomes an expert in one isolated area of production, thus increasing his efficiency” (Adam Smith). Detroit was not creating suitable jobs for high educated or professional people to work there; therefore, it caused the brain drain. Brain drain by definition means “the departure of educated or professional people from one country, economic sector, or field for another usually for better pay or living conditions (Merriam Webster Dictionary). This means that high skil...
Gang violence has been an issue within the United States since the colonization in the late 1400s. Although gang violence has always been around, larger more organized factions began arising in the 17th century. Today, according to youthinfo.gov more than 700,000 youth were treated in the ER for gang related incidents. While many actions have been taken against gang related, not all seem effective. While very interesting on how people are drawn into gangs, our government must implement more strict measurements against the clans of hooligans.
Gang activity and violence is a major problem in cities. Joining a gang makes a person feel a sense of belonging and need when one feels alone or unneeded. It’s a bad outlet for a person. Some examples of gang activity is graffiti, drive-by shootings, fraud, robbery, and assault. 100% of cities with a population greater than 250,000 reported to have gang activity and violence. Knowing the signs can stop the problem at the source.
These issues are of utmost importance, gang membership does not only present an issue on an individual level, but on a societal level as well. Gangs are well-known for their proclivity for violence, even to those who were simply in the wrong place at the wrong time. Youth gang crime is no longer limited to big cities; these problems have now spread beyond those boundaries into suburbs, small cities, and even rural areas (Spergel & Grossman, 1997). These organizations put us all at risk, and are a threat to public safety. Furthermore, these groups put our youth at risk and threaten to destroy their
The same concept was expressed by Edward O. Wilson (1992), father of sociobiology at Harvard University. According to him, females tend to be better equipped in characteristics like verbal and social skills, security needs and empathy than their counterpart. In the other, Males tend to be better in spatial ...
It is proven that the male and female brains differ, but can one prove that it affects the behavior? Many scientists would agree that ones behavior is determined by his/her gender. Although others are convinced that social conditioning is the cause for the differences between the male and female, it is very unlikely that biological differences play no role in behavior. The male and female brains differ not only by how they work, but also on the size. For example, Natalie Angier and Kenneth Chang, neuroscientists, have shown that the women’s brain is about 10 percent smaller than the male’s, on average, even after accounting for women’s comparatively smaller body size. Three brain differences that affect ones behavior are the limbic size, the corpus collosum size, and the amount of gray and white matter.
Schlaug, Gottfried, Andrea Norton, Kate Overy, and Ellen Winner. Effects of Music Training on the Child’s Brain. The Musician's Brain. New York Academy Of Sciences, 2005. Web. 14 Oct. 2013. .
In Birds, when one sex is a different size than the other, it is typically the male that is larger. However, in Hawks and Eagles, Falcons and Owls, the female is often larger than the male. Why?
When looking at the biological make up of male and females, there are both similar physical characteristics
According to Marıa et al., (2004) reduced locomotion activity increases stress due to the frustration of not being able to express some behaviors, for example, lack of access to nests (Duncan, 1998). Benefits of environmental enrichment to poultry is even distribution of birds in the available space, which permits more activity and locomotion that reduces disturbances and aggression as well as fear and stress (Leone and Estévez, 2008). Certain poultry behaviour has a strong incentive and poultry welfare is negatively affected if the birds are not allowed to express these behaviours (Linares and Martin, 2010). These authors stated that frustration, fear, and pain are the negative mental states of poultry and include increased aggression, displacement preening, and stereotyped pacing. Study from Linares and Martin (2010), confirms that extreme nervousness and hysteria are signs of poor welfare and they are associated with high population densities in large group, exposure to clamor, unexpected movement, or inexperienced circumstances, which result in skin trauma from scratches, spontaneous fractures, lessened feed consumption, decreased egg production, and reproductive disorders such as internal laying and peritonitis secondary to abdominal
There is no known creator of the Animistic religion. However, the Animistic belief is that all reality is infused with spirits and these spirits control everything that happens in the physical world. It is thought that strange and unexplainable events occur because people would do something to upset the spirits, and as a consequence, they create tragedies. Although there is no body for the spirits that they try to please, the way life is lived must be treated as a ritual to keep the spirits happy to keep the world at peace.