Saturday, December 13, 2008

SECRET WEAPON

Life is a battle where those better fit and prepared will have a better chance to reproduce and survive. It is an adaptation result of the product of natural selection. Which means that natural selection occurs when individuals vary in their hereditary attributes in ways that affect how many surviving they contribute to the next generation. Therefore, insects develop numerous defense strategies or mechanisms to avoid the capture by predators; such as chemical, camouflage, and an advertisement of unprofitability to deter pursuit. Chemical defense is more popular among insects and typically behave in conspicuous manner, for example, pump beetle's defend themselves by using an acidic and toxic spray.
When the pump beetle is attacked by a frog and there is the reaction chamber that happens when the predator(frog) attacks the pump beetle. And the beetle's use its toxic spray to defend from being captured by the frog. The beetle's have an enzyme that split up the explosion by forming a separate pulse of spray and the louder explosion is in sequence. As soon as the pump beetle's feel the contact with frog, it contracts its abdomen and releases the toxic from the end part of the abdomen in all directions.Pump beetle’s spray is very toxic and hot, when toads attack them its spray causes the toad’s tongue to burn and swell. Therefore, the pain and discomfort caused by the spray causes the frog to run away.

Odmir Rodrigues
12-12-08

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Sharing a Brain Between Sexes

The process of sexual selection can only exist as a product of neural-networking differences between the sexes of organisms. According to a recent study done at Yale University, "It isn’t what you’ve got — it’s how you use it". As we learned in class, females are "programmed" to be choosy, whereas males are wired for competition as means of gaining access to the females.

The staff of Yale researchers discovered the "unisex" brain via a study on the courtship dance of flies, a light-performance the male flies put on to impress females with the intention of copulating. Their study sought out to find what neurons were responsible for behavior in the courtship dance of flies, and how the neural circuits in males and females differed. As means of testing this, the researchers "genetically engineered specific neurons in the fly to respond to light". By doing this, the scientists could manipulate the neural circuits that control the behavior pattern directly. A laser light was then used to imitate the light performance, and the resulting neural reactions of certain nerve cells in the males was observed to identify the nerve cells responsible for this courting behavior. Finally, using the laser cue, the researchers were able to show that the same set of neural-networks were present in the female flies, who could actually be manipulated to show this behavior.

I find it interesting that the differences between the two sexes is only a matter of neural networking, and in fact, we can manipulate sex-specific behaviors.

Source: http://esciencenews.com/articles/2008/04/30/its.a.unisex.brain.with.specific.signals.trigger.male.behavior

Posted By: Helen Thi (12)

Lowland Gorillas, Not so much endangered are they?


Researchers found about 125,000 Lowland Gorillas in central Congo. They said this is about twice more than estimated world population of the gorillas. Steven Sanderson said that the group of researchers never thought this great numbers of the gorillas could live in such a large densities.

The researchers said that it is unfortunate that this fact is announced over the world because this will increase the extinction rate of the Gorillas. Lowland gorillas have been died and killed from diseases and huntings from contacting with humans. The Republic of Congo has become a place for logging and developments, which means that the habitat will be destroyed, and more contacts with humans. Thus large numbers of the gorillas will be killed from hunters, diseases, and destruction of habitats.

Sanderson said that, it is possible to save the gorillas in many ways however. Sanderson is helping to set a limit to loggin trees in Congo, and the Congo government is considering to build a wildlife park to save the lives of Lowland Gorillas.

link to the article:
http://www.npr.org/templates/story/story.php?storyId=93254830

-Yi, Jeongsang (12)

Friday, December 12, 2008

Disappearing Bees


There is a phenomenon going on among bees in North America that many speculated that they were somehow vanishing. Researchers have discovered that the worker bees are not actually vanishing but have come in contact with a virus called IAPV. When these bees have been infected many do not stay with the hive but leave their homes to go to other places to die, making it hard for researchers to keep track of their bodies. The researchers believe that the virus can only infect other bees and not humans or other animals. It should be noted that the virus is not the only cause that researcher suspect to be the reason for the decline in worker bees. Other factors like pesticides that are sometimes found in high levels in pollen and parasites are contributors to what is happening to the worker bees.


The increasing amount of bee death has caused colony collapses in some areas where bees are present. One of the first to notice this decline was Dave Hackenberg, a beekeeper. He began to take notice of the significant loss of bees in hives in Pennsylvania. He knew immediately that the losses were not the normal losses that bee experience during the winter but from something else. The declining numbers of worker bees led to many unsuccessful hives because there were not enough bees present to take care of things, especially the queen’s offspring. More research is presently being done to understand what is full happening to the worker bees.

Here is the link to the articles:

http://www.sciencenews.org/view/generic/id/39117/titlw/Honeybee_CSI_Why_dead_bodies_can%E2%80%99t_be_found


Posted By Debbie Theodat (12)

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Cannibalism of own Entire Offspring

It has been researched that many animals (especially fish) engage in filial cannibalism (the process of eating one’s own offspring). It is very rare to find an organism that has evolved this extraordinary cannibalistic trait. However, researchers have discovered that the long-tailed skink, Mabuya longicaudata, will eat their own entire clutch known as whole-clutch filial cannibalism in the presence of predators. It has been observed that at high frequency intrusions of an egg-eating snake the female skink will consume their entire offspring. Other factors are taken into consideration. If the female is in an unhealthy state, consuming their offspring to gain energy will be more beneficial for themselves so they can reproduce again later on when they are in a better state. It is a trade-off whether or not it is better to save the offspring or more beneficial to consume their offspring to increase the chances of her survival and increase the chances of reproduction in the future. Researchers observed that if many of the female eggs have been eaten by the egg-eating snakes then the female does not want to waste time and energy to protect and care for such few offspring. This is when the cost of parental care outweighs the benefit of caring for their young. Therefore, instead of putting energy into the few offspring she will consume them for energy and try to successfully reproduce again. Very little is known about this cannibalistic behavior in animals (especially in reptiles) and is an ongoing study that researchers are gathering information about to better understand the costs and benefits of parental care and how organisms go about making these decisions that they have successfully evolved from overtime.

You can read more about this article here.

-Carlos A. Varela (Week 12)

Thursday, December 11, 2008


Zebra Finches Show that Genes and Behavior is a Two-Way Street

A review published in the journal Science by three prominent biologists found that gene expression can change in response to environmental information in three species that they have studied. They believe that this points to a trend for most or all species. One of the scientists, Gene Robinson (an ironic first name) states: "there is a dynamic relationship between genes and behavior,"..."Behavior is not etched in the DNA."

One of the authors published a landmark paper in 1992 by David Clayton, therein he described how just after a zebra finch hears a song by another male of the species, the expression of a certain gene increases in the forebrain of the animal. The gene codes for a single protein which regulates the expression of many other genes. It is very likely that this regulation causes some large scale changes in the finch's brain which allows it to better respond to a potential threat in its environment.

Another example is in the hives of honey bees. Bees in the hive have different jobs to attend to and foragers tend to be the older members of the hive. It is well known that if you remove older foragers from a hive, younger bees will replace them and adopt foraging behavior. Robinson published a study in 2002 which found that foragers express a certain gene that is responsible for their behavior as well as a pheromone. When this pheromone is in low concentration, younger bees begin to express the foraging gene and begin releasing the pheromone. This feedback system keeps just the right number of foragers in the hive at all times.

More generally, the review stressed that behavior's influence on gene function is no longer new to neuroscience and is becoming a well-established idea. We will most likely discover similar patterns in most animal behavior and this is a remarkable step in our understanding of the brain. Clayton puts it figuratively: "Experience is constantly coming back in to the level of the DNA and twiddling the dials and the knobs."


Jimmy Sullivan

December 12, 2008 (week 12)

http://www.sciencedaily.com/releases/2008/11/081106153538.htm

Friday, December 05, 2008



And the Artist is…An Elephant?


As a close to the semester, I thought it would be nice to write about a good cause that is still related to animal behavior. This behavior is quite unexpected , but it shows us how amazing and intelligent animals can be. This is also an example of a learned behavior.

In 1999, two artists started the Asian Elephant Art & Conservation Project at the Bali Elephant Safari Park. The artists taught the elephants how to paint in an attempt to “raise awareness and funds for the Parks own Elephant Foundation.” The Elephant Foundation raises money to help the endangered Indonesian elephants. The elephant artists hold the paintbrushes in their trunks to paint pictures, which are then sold by the park.

Click Here to see a video of an elephant painting.


http://www.baliadventuretours.com/BAT-Elephant_Art.htm


Posted By: Sasha Rogers (11)



Update:
Elephants learn to paint the same way humans do. First, the artist teaches the elephant how to hold the brush with his trunk. Once the elephant can do this, it is allowed to paint whatever it wants to paint. Those picture that you see an elephant make of another elephant form, etc. are probably due to long training with the artist, who has been using the one example painting to teach the elephant. Other than the first example painting that has been burned into the elephant's memory, the elephant creates works of art that often look less structured, but it is still art. The differences in paintings is based on the different ways an elephant holds the paintbrush and the supplies available to him at the time.

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HUMAN CONSERVATION WORKERS FOR LUNCH



In an effort to save the endangered tiger, Nepal conservationists are working with village communities to restore tiger habitats along the border of India. Unfortunately, for the humans, the tigers are apparently "taking advantage" of the new food supply as an alarming number of human killings have been reported in the newly formed tiger habitats.

According to the article, " The Dark Side of Tiger Conservation" posted on ScienceNow, "Hunting and habitat destruction have reduced the world's wild tiger population from 100,000 a century ago to 5000 or so today." The Napalese government has recently made efforts to build tiger habitats in forests along tiger reserves in order to increase the tiger habitat. Local communities are working together to help manage these new habitats. This program, called the "buffer-zone management program", came to "Royal Chitwan National Park, a UNESCO World Heritage site along Nepal's southern border with India", when local communities pulled their livestock off lands surrounding the park and turned their grazing space into tiger habitat. This action came at a slight price, however, as the number of conflicts between humans and tigers increased. From 1979 to 2006 there were a reported 88 killings - with a nine-fold increase in killings per year once the new habitats (aka buffer zones) were established and populated with tigers.

This is good news for the tiger community as it obvious evidence for the success of these buffer zones in the conservation of tigers. A problem arises as the increase in attacks towards humans increases the aggression the villagers give to tigers ( they are more likely to kill or poison the tigers in defense or retaliation. A number of solutions have been addressed including educating the villages on how to go about daily activities and stay out of the tiger's way to fitting tigers with radio collars so, people will know where they are. Whatever the solution, this is an interesting comparison between behaviors of a species who is showing altruistic behavior towards another who has no capability of understanding it.

You may read the posted article here.

Maura Mulvey
12/5/08


Pregnant Males? Seahorses are Nature's Mr. Mom

          That's right guys. Male Pregnancy. It seems that seahorses have brought fathering to a whole new level. Generally in nature we may think of it as normal or usual for a female to produce eggs, give birth, and spend most of their time caring for their offspring. The male, on the other hand, makes his one contribution and can then spend the rest of his time on the couch watching football. However, over time it seems to have been more beneficial for seahorses to reverse this role, and with it the inversion of "Darwin's other big idea" of sexual selection. 

          So how does this work, you ask? Well, females haven't begun to produce sperm, but rather deposit their eggs. When seahorses mate, the female inserts her ovipositor into the male's brood pouch (which grows on the outside of the male's body). The female then deposits her unfertilized eggs into the pouch, upon which the male releases sperm for fertilization. The brood pouch is highly vascularized and specialized  for maintaining and caring for the developing embryos. For instance, the male controls osmoregulation of the salt concentrations, as well as providing oxygen and nutrients through a placenta-like structure until he gives birth. 
You can this this really well here: Seahorse Birth Video

          It seemed fit to talk about sexual selection since we just recently covered it in class. Recall, that because of the differences in reproductive strategies, that females generally invest more time and energy into reproduction then males to. Females use energy to form eggs and take time to care for their young, where as males spend little energy producing sperm and then spend little or no time caring for their young. As a result of this, the males have a higher reproductive rate and are therefore more "promiscuous". The opposite is true for the females. The final point, and Darwin's main idea, is that from this the females will enable to choose who their mates are because of the high availability, and males will have to compete for mate because low availability. Eventually, the males will develop physical secondary sexual traits to aid in being chosen by females. This usually is in the form of coloring, a behavior, or an exaggerated part of the body (e.g antlers).  

          So what does male pregnancy (role reversal) do to Darwin's sexual selection theory? Well, it would make sense for everything to be reversed, that being the males become choosy and for the females to develop secondary traits like bright colors. Although this does occur in other species with male pregnancy (such as the polygamous pipefish) it doesn't occur in seahorses. Because seahorses form monogamous pairs during breeding, an equal male to female sex ratio is created. Since there are enough mates for everyone, there is low competition. Therefore there is no need for the evolution of a secondary trait. What does agree with the role reversal, is the competitive behaviors exhibited by females during mating and courting, a trait that is normally attributed to males. In addition to this, the males then become choosy. 

          So guys, if you plan on having kids one day, be thankful you're not a seahorse. For the ladies, if evolution takes a step in this direction, perhaps we'll be the ones on the couch. If seahorses can do it, why can't we? 


Posted by: Amanda Sceusa (Week 11)

Update: 
Many of the questions I received in the comments, were asking why this reproductive strategy (male pregnancy) is beneficial and how has it evolved. After doing some internet research I discovered that there is really no answer yet. I stumbled upon many proposals for this research topic, like this one HERE, which is attempting to trace the evolution genetically to try to find some answers. This research is scheduled to end in January 2009, so keep your eyes out for updates about these questions in the Spring semester. Even though there are no concrete answers yet, there are still many hypotheses about why male pregnancy actually occurs in nature. An article to follow up on some of the clues to the genetic dichotomy can be found HERE One hypothesis is over the course of time, a gene that would normally help liver and kidney function, was altered to also help osmoregulate the brood pouch. "Genetic moonlighting" is what they called it, or basically instead of solely aiding liver and kidney function, it also helped the brood pouch. Other hypotheses can be made just by thinking about the costs and benefits of this systems. There must be at least SOME benefit to this strategy if seahorses are still alive, no? We will have to wait and see...
As far as other species that exhibit male pregnancy: the Pipefish, which happens to be in the same family as seahorses; Syngnathidae which includes over 200 species. 




Solar-powered Sea-slugs live like plants


The lowly sea slug, “Elysia chlorotica,” may not seem like the most exciting of creatures, but don’t be fooled: it behaves like a plant and is solar-powered, says a Texas A&M University biologist who has been studying these tiny creatures for the past decade and, along with collaborators from several universities, has identified a possible cause of their ability to behave like plants.

Plants can be compared to solar-powered machines—their cells contain tiny organelles called plastids that trap sunlight and convert it into energy by photosynthesis. The sea slug, however, works a little differently. Its main food source is a specific type of alga. “It makes a cut in the alga, sucks out the cytoplasm [the material inside the alga] and digests most of it. But there’s a twist—it retains the plastids that trap the solar energy. These plastids remain in the slug, continue to photosynthesize and provide food for the slug. In effect, the creature becomes a solar-powered slug and is able to make its own food like plants do.

Photosynthesis needs around 2,000 to 3,000 genes, and animals do not have many of the critical genes.Researchers found that the slug has at least one gene required for photosynthesis in its nuclear genome, which has never been found in any animal. The critical thing is the plastids come from the alga, but the slug nucleus contains at least one, and probably more of the genes required for plastid functioning. The slug needs the alga to mature and complete its life cycle. It is totally dependent on the alga to survive. Once the slug has acquired a sufficient amount of plastids it can survive, like plants, for at least nine months by trapping solar energy and converting it into food.

This means the “baby” slugs are born with genes that support photosynthesis, but they have to gather their own plastids. Researchers on this matter say that if the slug and the alga both brave the ever-changing climatic conditions, the slug might evolve into a truly photosynthetic animal!!

http://www.sciencedaily.com/releases/2008/11/081125112958.htm

Brena Sena (11)


New Cancer Detecting Technology


Today there are only a few tools available to detect cancerous cells in the blood, and all of them are not very accurate in detecting cancer at its earliest stage. That is due to the fact that at that point, there is a very small concentration of the cancerous cells in the blood. Because of that, we have not yet found a method that can diagnose cancer at its very early stages. This may very soon change however, because of the work of Stanford professor of materials science and of electrical engineering Shan Wang. He along with her team of researchers have created a blood scanner that uses magnetic nanotechnology to spot cancer proteins and markers in the blood stream. Wang is very excited and optimistic that the technology will someday save lives by detecting cancer early or by helping doctors select more effective therapy. "The earlier you can detect a cancer, the better chance you have to kill it," he said. "This could be especially helpful for lung cancer, ovarian cancer and pancreatic cancer, because those cancers are hidden in the body."

The sensor they have developed is called the MagArray. It works by first tagging cancer proteins with tiny magnetic particles. This is instead of using electric charges or glowing particles, which is what was used previously in other detectors. The detector itself has a silicon chip with 64 sensors that moniter changes in the magnetic field, which occur when the sensors attach to the cancer related proteins floating by. This breakthrough technology is much more accurate at detecting cancer, as a matter of fact, it can detect these cancerous proteins at a level 400 times lower than a current commercial detecting kit known as ELISA. This new technology looks very promising and will be very helpful in aiding doctors and improving healthcare as far as cancer in humans is concerned.

The complete article can be found here.

Ahmed Sandakli (11)



Bad Bio-Fuels!

In today’s green world it is easy to get wrapped up in the idea in renewable fuels. However, using renewable resources are grown at the expense of other things that grow in that place. We all know the argument that displacing food crops by biofuls can increase food prices. However, there is another problem, the plants growing originally are actually better for the environment than removing them for Bio-fuels.

Researchers point to the use of palm oil as a Bio-fuels. This is done at the destruction of tropical rainforests. By destroying a large carbon sink and planting oil palm it take 600 years to offset the destruction. The main reason for this is for wealthier nations to claim a lower carbon footprint not to actually help the envirment. However, by planting them on grassland instead of rainforest it takes only 10 rears to break even.

Carbon reduction is not the only damage palm oil plantations face. Another problem is the decrease diversity. As we replace many different plants with one species we deplete the number of habitats and decrease the diversity in one of the most species rich regions of the worlds. Clearly we need to fix something but we need to do it in an ecologically sound way.

http://www.sciencedaily.com/releases/2008/12/081201105657.htm

-Matthew Sousa(11)

Thursday, December 04, 2008

Male Redback Spiders Can Speed Up Their Sexual Development


Sexual selection is a subset of natural selection in which traits are evolving. We discussed several examples in class of sexual selection such as the iris elk antlers, manikins and their gaudy plumage, peacocks and their tail feathers, bower birds, and of course many more. All of these sexually selected traits decrease the survival of these animals. So for these sexually selected traits to evolve the advantage to the individual needs to be above and beyond the cost of survival. The males that evolve the sexually selected trait will reproduce much more then the males that do not evolve the trait.

In an article on Animal planet a study addressed male redback spiders speeding up their sexual development in order to beat their rivals to the females. The male and females exhibit extreme dimorphisms. The females are 100 to 200 times larger then the males. The female can live for up to two years and yet the males only live for only four to eight weeks! The males have to compete for the females, typically eight males will compete for one female. When the male mates with the female he leaves inside her a sperm plug so its important for the male to be the first to mate with her to pass his genes on. So there's a need for these male spiders to quickly mature so that they can mate first.

The males remain in the web where they're born until wind conditions allow them to leave and build their own web. At their own web they build up their fat reserves after molting since when he goes to find a female he spends all his time trying to locate her and no time eating. The spider needs to decide how much time to spend building fat reserves before trying to locate his mate. The males make their decision by smelling for the density of females around them. If there were many females in the area he wouldn't need to be well fed since he's not traveling far, but if there were few females he would need to store more fats to make the journey. If their are no females around the males will develop at a normal pace.

This study explains why there's a variation in the size of male redback spiders in the wild. Animal behaviorists typically would blame it on that the smaller males were not able to obtain enough resources but in this case the males are exchanging their body size to be the first to mate with the female to ensure his genetics are passed on.

Jennifer Smith (11)