ddoyleperkin's blog

Code breaking is a method by which certain animals gain a leg up on their competition by adapting the behavior of another species. Code breakers are interesting because they have gained the ability to learn certain niche behaviors of other species and use them to their advantage. For example, fireflies have the ability to bioluminesce. Male fireflies flash their thorax many times in pursuit of females. Each species of firefly have different flashing patterns. Males will flash continuously, looking for a female, while a female will flash once or twice very quickly to let the male know she wants to mate. There is a species of firefly that will use the flashing pattern of another species to attract a male. Once the male has flown over to the culprit, it will promptly be eaten. This code-breaking behavior is not as rare in organisms as one might think. Even humans have unknowingly become code breakers. Earthworm grunting is an example of human code breaking. Worm grunting is a method of harvesting earthworms and it involves placing a wooden stake in the ground, vibrating that stake with a flat iron, then waiting for worms to rise up from the ground. The vibration of the wooden stake mimics the burrowing of a mole, causing earthworms to leave their burrows and come up to the surface of the ground. Code breaking is an efficient way for one species to gain an advantage over its prey.

Prezygotic and postzygotic are important when attempting to understand how it is possible for two species that may live in the same area to coexist without mating. If two species do happen to mate and produce offspring, isolation still occurs. Postzygotic isolation occurs after an egg has been fertilized and an offspring has been produced. There are two major forms of postzygotic isolation: hybrid inviability and hybrid sterility. Hybrid inviability refers to the extremely low fitness of an offspring from two different species. This low fitness often leads to the death of the offspring, inhibiting the continuance of this potential new species. Similar to hybrid inviability, offspring is still produced with hybrid sterility. This offspring, however may have high overall fitness, but cannot mate because of sterility. This type of isolation can be seen in mules, the offspring of a horse and a donkey. While mules can survive perfectly fine, two mules cannot create an offspring.

Prezygotic and postzygotic isolation are two separate ways in which species are disallowed from mating with one another and producing a fertile offspring. Prezygotic isolation refers to the prevention of the fertilization of eggs while postzygotic isolation refers to the prevention of the production of fertile offspring. There are multiple different ways species are isolated before the egg can even be fertilized. Habitat isolation is one of the most significant forms of prezygotic isolation. If two species do not live in the same habitat, there is no chance that an egg of one species will be fertilized by another. A similar prezygotic measure is mating season isolation. A species that mates in the spring will have no chance of mating with a species that mates in the winter. Mating season isolation ties in closely with behavioral isolation. The time of year that a species mates is certainly a behavior, but behavior is not limited to mating seasons. If a species has certain pre-mating rituals, another species may not be familiar with this ritual, making it very difficult for the two species to agree to copulate. Still, two species might have similar enough behaviors and similar enough mating times that there may be a chance that the two could mate. In this event, between certain species, there is something known as mechanical isolation. Mechanical isolation refers to the physical inability of two separate species to mate. For example, spiders have penises shaped specifically for spiders of the same species, similar to a key and a lock. It would be physically impossible for a spider of one species to mate with another.

A recent gene editing method called CRISPR-Cas9 is a technology that allows scientists to alter DNA. Using technology like this makes it possible for genetic data to be edited at specific parts of the genome. This editing entails the removing, adding, and altering of current genetic material. CRISPR is short for clustered regularly interspaced short palindromic repeats. Cas9 refers to the associated protein, CRISPR-associated protein 9. This system of gene editing was derived from a naturally occurring system in bacteria. Bacteria can take the genetic material of viruses and produce RNA segments referred to as CRISPR arrays. If the virus attacks again then the bacteria will use the CRISPR arrays to attack the virus DNA, then send the Cas9 protein to cleave the virus DNA, rendering it ineffective. In vitro, the process works similarly. Scientists will create guide strands of RNA with specific sequences to target specific sequences on strands of DNA. Once the DNA has been targeted, the associated enzyme will cleave this region of DNA. After the DNA has been cleaved, the cell’s own repair machinery is used to replace the missing segment. This cleave, then repair process is a huge breakthrough in the field of gene editing, allowing scientists to alter whichever segments of DNA that they can synthesize an RNA strand for.

A microbiome is a very important community of microbes that live in and on the organs of the human body. Microbes living on your organs sounds like cause for concern but the human microbiome is actually very important in both defending the body against disease maintaining normal bodily functions such as digestion. Microbiomes change often, however, if the balance of populations of microbes in the human body are disrupted, then disease may follow. Microbes start to colonize every inch of the body as soon as you are born; the first batch of microbes comes from your mother. If you are born vaginally, you would be covered in your mother’s vaginal microbes. If you are born via a cesarean section, then you would be covered in skin microbes; a different type of microbe entirely. Some microbes in the birth canal actually help an infant digest its first meal. Functions like digestion are not the only purpose of the microbiome. The microbiome also protects you from harmful bacteria and one example of this is acne. Acne is caused by a bacteria called P. acne, that if more prevalent than good microbes, will cause the widespread blemishes observed in people with acne. These imbalances of microbes can be seen in more communities of organisms besides those residing on the face, which is why it is important to remain mindful. Antibiotics, drugs designed to kill bacteria, can be a problem for the balance of healthy microbes. While antibiotics are effective at ridding the body of harmful bacteria, they also kill beneficial bacteria. This collateral damage can often lead to declines in the immune system, especially in children with developing microbiomes. The nuances of the microbiome are becoming a more prevalent research field as we continue to uncover the importance of the film of protective bacteria covering our bodies.

A microbiome is a very important community of microbes that live in and on the organs of the human body. Microbes living on your organs sounds like cause for concern but the human microbiome is actually very important in both defending the body against disease maintaining normal bodily functions such as digestion. Microbiomes change often, however, if the balance of populations of microbes in the human body are disrupted, then disease may follow. Microbes start to colonize every inch of the body as soon as you are born; the first batch of microbes comes from your mother. If you are born vaginally, you would be covered in your mother’s vaginal microbes. If you are born via a cesarean section, then you would be covered in skin microbes; a different type of microbe entirely. Some microbes in the birth canal actually help an infant digest its first meal. Functions like digestion are not the only purpose of the microbiome. The microbiome also protects you from harmful bacteria and one example of this is acne. Acne is caused by a bacteria called P. acne, that if more prevalent than good microbes, will cause the widespread blemishes observed in people with acne. These imbalances of microbes can be seen in more communities of organisms besides those residing on the face, which is why it is important to remain mindful. Antibiotics, drugs designed to kill bacteria, can be a problem for the balance of healthy microbes. While antibiotics are effective at ridding the body of harmful bacteria, they also kill beneficial bacteria. This collateral damage can often lead to declines in the immune system, especially in children with developing microbiomes. The nuances of the microbiome are becoming a more prevalent research field as we continue to uncover the importance of the film of protective bacteria covering our bodies.

DDT, or dichlorodiphenyltrichloroethane, is a colorless and tasteless chemical compound developed as an insecticide and its use was banned because of its role in the increased risk of serious health conditions in humans and animals alike. DDT was at the height of its popularity during the second World War. During this time, DDT was used to prevent diseases such as malaria and typhus. Though it was an effective insecticide, it was cause for concern when the chemical would also kill beneficial insects as well as birds and fish. Not only did DDT kill birds, but it also caused egg-shell thinning in Perregrine Falcons. This egg-shell thinning would make it much more difficult for the falcons' young to be born. The egg-shell thinning was not the extent of the damage done by DDT. This harmful compound is thought to be a carcinogen as well as an endocrine disruptor. An endocrine disruptor is a chemical that interupts an endocrine system. In this case, a chemical called DDE is formed from DDE when it loses hydrogen chloride. DDE is an androgen receptor antagonist, meaning it will bind to the same receptor that male sex hormones bind to, decreasing the effect of certain hormones such as testosterone. The deleterious human and animal effects caused by DDT were far too prevalent to allow it to continue being used and it was banned in the United States in 1972.

One system within the endocrine system, known as the male HPG axis, is responsible for a variety of different physiological functions such as spermatogenesis and the development of sex organs. HPG axis stands for hypothalamus-pituitary-gonad axis and is characterized by neurons in the hypothalamus region of the brain releasing hormones that signal receptors in the anterior pituitary gland. The pituitary gland then releases its own hormones that signal receptors in the gonads and leydig cells, initiating its physiological functions. The hypothalamus releases a hormone called GnRH, or gonadotropin releasing hormone. Hormones released from the hypothalamus set for the pituitary travel through a specialized pathways called the portal system. Once the GnRH has bound itself to receptors in the pituitary, two more hormones are released from the gland: LH and FSH. LH, or luteinizing hormone, will leave the pituitary and enter the bloodstream, traveling to leydig cells. This will stimulate the leydig cells to release testosterone, initiating spermatogenesis and reducing the secretion of LH from the pituitary. FSH, or follicle stimulating hormone, however, takes on a different role. FSH goes straight to the testis to upregulate the production of sperm.

The Noctuid Moth or Owlet Moth, living in arctic and antarctic regions, exhibits a seemingly complex but quite simple method of escape from predators. Noctuid Moths are hunted mostly by insectivorous bats. These bats hunt using echolocation, so in their evolution, the moths have had to develop a means of countering this. Their answer to echolocation is a simple neural reflex circuit. The moths use ears located on their thorax to listen for the screeches of bats. Their ears contain two receptors, A1 receptor and A2 receptor, sensing location and proximity respectively. These receptors are connected to a group of interneurons in the thorax of the moth called the thoracic ganglion. This thoracic ganglion is connected to wing muscles on the opposite side of the moth. Once the sensory receptors in the ear receive enough stimulation from the screeches of the bats, the moth will automatically react, dodging and diving. It seems as though the moth is processing complex thought in avoiding the bat, but is actually just undergoing a series of reflexes as the chase goes on.

Culture, even in non-human species such as chimpanzees, can be defined as the alteration over time of learned behaviors. One such learned behavior is the chimpanzee’s hoot. The hoot is a call made by chimps in order to identify one another. This identification is possible because of the fact that this behavior is learned, meaning it can differ from population to population. In other words, one troop of chimps will have a different hoot than another troop. As it turns out, chimpanzees are both very aggressive and very territory when it comes to chimps outside of their troop. Because of this, they will often engage in wars between troops. These wars are possible because one population can locate another via the unfamiliar sound of their hoot. Scientists have been able to confirm this through the cultivation of artificial chimpanzee troops in enclosed sanctuaries. Injured or orphaned chimps rescued from labs or the wild will start with their own unique, learned hoot before being assimilated into the sanctuary. Once successfully assimilated, the chimps will converge on one identical hoot that they may use to communicate with one another. This convergence is a perfect example of culture within a non-human species.