Photo by Chromalux

Many animals have a type of mating call which attracts the female to them in order to mate.  If a female is attracted to a charismatic male and they produce offspring, would their offspring be attractive as well?

Scientists have been searching for evidence to be able to determine if attractiveness could be hereditary. To do this, scientists in England used the Drosophila simulans fruit fly. In this species, the female is attracted to the male by their personality and flirtations.

What kind of personality and flirtations? Well, the Drosophila male flies sometimes have a “courtship song” or a mating song that attracts the female to the male. The way that they produce these “songs” is by the movement of their wings. Certain patterns and pulses produce different types of “songs”.

Another way that makes the males attractive is the pheromones that are produced.  Pheromones are sometimes sex-specific and are released by certain glands or cells to trigger the behavioral response of the opposite sex of the same species. Specialized sensory structures or cells recognize pheromones.  The neurons are thought to be responsible for the detection of pheromones in Drosophila.

The scientists paired the males and females together and looked at the average time it took them to mate. By using common sense, if they mated quickly, such as 5 minutes, then they concluded that those males are attractive to the females. If it took a longer time to mate, then most likely they do not have as much charisma as the other flies.

The offspring (sons) of the flies were paired with single females. They repeated their step in observing the amount of time it took them to mate. Just like the scientists thought, the attractive males that they started with, in fact, DID produce attractive sons!

After seeing this, scientists wondered if this same idea could be spread across to all species.  Does this mean attractiveness is hereditary in other insects or species as well?

David Hosken, an evolutionary biologist who worked on the study said, “Extrapolating from one species to another closely related species should be done with caution. Knowing lots about one species may tell you little about another.  We must remember this when we make hypotheses of other species.”

Is this kind of attractiveness shown in Drosophila also hereditary in humans?  What similarities do you notice between Drosophila and humans? Do you think it’s impossible to pull predictions about our species from Drosophila?

Jackie (the author of this post) examines a sample of anesthetized Drosophila melanogaster!

Molecular Level – Operon

The operon is a region of bacterial DNA that regulates gene expression in bacteria. The operon consists of four major parts: structural genes, regulatory gene, the promoter gene, and the operator. Structural genes are genes that code for enzymes needed in a chemical reaction and these genes will be transcribed at the same time to produce specific enzymes. The regulatory gene codes for a specific regulatory protein called the repressor, which is capable of attaching to the operator and blocking transcription. The promoter gene is the region where the RNA polymerase binds to begin transcription. The operator is the region that controls whether or not transcription will occur.

 
Cellular Level – Nucleus

The nucleus is considered to be the control center of the cell; it controls everything that occurs inside the cell, including the cell’s ability to reproduce. The nucleus is also the home to the cell’s DNA, which is packaged into chromosomes. It is found in the cells of all multicellular living things such as: plants and animals.

Photo by Biology Flashcards

Organismal Level – Pituitary Gland

The pituitary gland is in charge of releasing many hormones that reach other glands to stimulate and secrete their hormones. The pituitary gland has two parts: the anterior and the posterior, each with their own set of hormones.

The anterior pituitary secretes six hormones, three for regulating growth and three for regulating the reproductive systems. The six hormones include: the growth hormone (GH), the adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin. GH stimulates the growth throughout the body, specifically targeting bones and muscles. ACTH is the hormone that stimulates the adrenal cortex to secrete glucocorticoids and mineralocorticoids. Lastly, TSH stimulates the thyroid to secrete thyroxine. FSH stimulates follicle to grow in females and spermatogenesis in males. The anterior pituitary is actually regulated by the hypothalamus.

The posterior pituitary, secretes only two hormones: the antidiuretic hormone also known as vasopressin as well as the hormone oxytocin. The antidiuretic hormone regulates the water intake by nephrons. Oxytocin stimulates the contraction of the uterus and the ducts of the mammary glands.  

Photo by Reigh LeBlanc

Populations – Hardy Weinberg

The Hardy-Weinberg law states that even with all the shuffling of genes that occur, the approximate frequencies of genotypes in a population still prevail over time. The frequency of alleles is depicted in this equation: p + q = 1. This can also be calculated by determining the frequency of the genotypes in a population using the equation: p^2+2pq+ q^2. In these equations, p stands for dominant allele, while q is for the recessive. The law states that populations will be in genetic equilibrium only if it meets the five conditions: there is a large population, there are no mutations, no immigration or emigration occurs, random mating occurs, and that no natural selection occurs. Through this, the Hardy-Weinberg Law regulates variation in a population.

Population – Growth Characteristics

There are two different types of population growth and regulation, r-selected and k-selected. The characteristics of r-selected growth include: late maturation, fewer offspring, larger young, longer life spans, more parental care and intense competition for resources. Then there is also the is the K-selected population, whose characteristics include: early maturation, a large number of offspring, smaller young, shorter life spans, less parental care and little competition for resources. Still though, biological and environmental factors can affect these characteristics. These two regulate the growth of an animal.

Photo by Duncan

Photo by Leo Reynold

Community Level – Decomposers

Decomposers are organisms that break down organic matter into simple products. The most common decomposers are fungi and bacteria and they serve basically as the “garbage collectors” of the community. Eventually in a community everybody will yield to a decomposer. Now, the reason this has to do with regulation is that decomposers regulate or help clean up our communities, making them capable of living comfortably in them.

Photo by I Need Coffee

Biosphere – Ozone Layer

The ozone layer is a layer in the earth’s atmosphere made up of O3 that absorbs 93 to 99 percent of the sun’s ultraviolet rays, thus protecting us from them. The ozone layer is mainly located in the stratosphere and the thickness of the layer depends on the area on earth.

Photo by Nasa Goddard Photo and Video

Photo by cstmweb

In a sequence of experiments from 1909 to 1911, Ernest Rutherford discovered that the majority of an atoms weight was concentrated in the center called the nucleus. He discovered this by completing and analyzing a gold foil experiment. Rutherford fired alpha particles, relatively massless particles consisting of two protons and two neutrons, at a thin sheet of gold foil. Rutherford wanted to measure how much the alpha particles were deflected because the alpha particles have a positive charge and the electrons have a negative charge. The electrons were expected to slightly alter the trajectory of the fired alpha particles. Contrary to Rutherford’s hypothesis, the alpha particles were hardly deflected. After analyzing the experiment, Rutherford concluded that the mass of the atom was not evenly distributed as previously thought. The mass of the atom, in fact, was highest in the center of the atom called the nucleus. Rutherford’s hypothesis for this experiment was disproved, a key part of Science as a process. It is acceptable in science to hypothesize incorrectly as long as you can explain the correct outcome of the experiment.

Tangerine fruit stalk; Photo by Tatcher a Hainu

 In 1838, Theodor Schwann and Matthias Schleiden were sitting together speaking about their study of cells. Schleiden described plant cells as having a nucleus in the center. This directly correlated with Schwann’s observation of animal cells. The two immediately looked at each others slides and came up with a cell theory which stated:

1) The cell is the unit of structure, physiology, and organization in living things.   

2) The cell retains a dual existence as a distinct entity and a building block in the construction of organisms.

3) Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation).

In this case, Schwann and Schleiden used many different processes of Science. They Experimented, inferred, and collaborated in order to come to their conclusion.

Louis Pasteur; Photo by Euclid vanderKroew

Louis Pasteur, a French scientist, disproved the theory of spontaneous generation. This theory stated that living organisms could be made from non-living matter. In order to disprove this, Pasteur boiled meat broth into a flask and shaped the flask into an S shape. Air could enter the S shaped flask, but small microorganisms could not. After many days, as expected by Pasteur, no organisms grew in the broth. In the broth that Pasteur left in a regular open flask, however, organisms grew. This proved that organisms couldn’t just appear. Pasteur hypothesized correctly and accurately conducted an experiment to prove his hypothesis. This was one of the landmark experiments at the time, disproving a common theory.

Photo by Roberto F

Karl von Frisch, an Austrian ethologist, studied honeybees and showed that they use dance to communicate food locations to other bees. Von Frisch noticed that when one honeybee found food, others appeared around the food. He then studied the bee’s movements when it found the food. He observed two different movements or dances. A round dance, which tells other bees to search for food close to the hive and a waggle dance which told other bees the direction and distance to fly toward the food. This study on a population of honeybees helped scientists further understand the movement and food searching methods of the bees. Von Frisch mainly used the scientific process of observation and analysis to reach his conclusions on honeybee dances.

Photo by Storm Crypt

Recently, Harvard University has conducted studies on invading, nonnative plant species, especially those in Massachusetts. The Alliaria petiolata, a common invader in Massachusetts’s forests. This plant threatens other local plants such as sugar maple and breech in the forest. They also studied that the Alliaria petiolata spreads in low light areas. The study of the population of plants in Massachusetts forests help Harvard scientists figure out how to get the nonnative species out and how to help the native plants survive. These scientists observed the plants for hours in order to come up with a hypothesis on what the invading species is doing and a way to help the native species survive.

Photo by KTVee

In 1988 James Lovelock published a book speaking about his Gaia hypothesis. This hypothesizes that all living things have a regulatory effect on the earth’s environment that promotes life. Lovelock came upon this hypothesis while looking at the atmosphere of Mars in its equilibrium. He analyzed that the earth’s atmosphere was never in equilibrium. This highly controversial hypothesis has not been proven. Most scientific discoveries start out as unproven hypothesis. Scientists then conduct experiments to prove or disprove hypothesis and eventually come to a final conclusion.

LOVING the emphasis on invertebrates on this blog.  Quite often the human-world forgets that over 95% of the organisms on this planet are spineless!  I recently read a paper in my favorite journal, Behavioral Ecology and Sociobiology, which emphasizes the complexity and sophistication of invertebrates.

The Complexity of the Mountain Pine Beetle

One of the most profound biological disasters affecting British Columbia, Canada (the province where I live) is the infestation of our forests with the mountain pine beetle (Dendroctonus ponderosae).  Over 14 million hectares of forest is infested with the pine beetle, causing massive destruction of our forests (trees infected with beetles are eventually killed).  A combination of warm winters and prevention of natural wildfires has made our mature lodgepole pine forests an easy target.  Most people think about the wrath of the pine beetle at the large scale of its devastation, however, very few think about the beetles as individuals.

What a mistake!

It turns out that the colonization of a new tree is a very complicated process at the level of the individual.  When organisms live in groups and forage in groups (as the beetles do), there are individuals that rist being the first one to attack a new prey item or to colonize a new site.  These ‘pioneer’ individuals often face some kind of adversity for being the first to investigate a new site.  For the pine beetles the first individual to attack a new tree often suffers a greater risk of mortality (from the trees’ defenses) and a decreased reproductive rate.  In a set of detailed experiments, investigators found that beetles with an intermediate body condition were the most likely candidates to pioneer a new site.  Those in great condition opted out, as did those in poor condition.  This provides support for the ‘desperation’ hypothesis, where individuals base their foraging decisions on their current needs.  The new pioneers still had the physical ability to move to a new site (unlike individuals in poor condition) BUT they weren’t in good enough shape to simply sit back and wait for someone else to do it (a luxury enjoyed by the individuals in great condition).  In addition, beetles were more likely to pioneer to new sites based on the time of year (and hence the liklihood of being followed to a new site by members of their group) and the overall size of the tree.

So, far from being ‘just another pest’, the mountain pine beetle displays a complex sophistication when it comes to decision making.  Time for the Homo sapiens to display a little humility!

Reference: Bark Beetle Who Goes First

Jack playing a video game

***Play Jack’s Game BEFORE Reading the Post!*** 

 Click Here to Play Jack’s Game:  motherboarddefence

Sometime in your life, you have heard rumors that video games are bad for you. If you are a kid, you’re parents have probably told you that hundreds of times. If you’re a parent, you’ve most likely said it yourself. Well, guess what, the kids were right. It seems that many people, maybe even yourself, believe myths about video games without thinking about possible advantages.

Luckily for gaming enthusiasts, these myths have been shot down by many researchers and scientists.

First off, the games-violence connection is one of the myths that is explained by Henry Jenkins, an MIT professor.  Shooting and fighting games don’t directly make you violent, the violence that occurs would have happened anyway. Shooting games require an enormous amount of sensory ability and brain function. From knowing how much ammo is in the five or so guns that you switch through to remembering advantage points in a map, the game requires so much thought that it helps train your brain to tackle many tasks at once. Over time, sensory abilities increase in general. Reaction time will improve and eventually an ability to isolate important sounds will develop.

Some people may argue that video games aren’t very expressive. “Why waste your time playing video games?” Just take a look at games that exist today. Games like Scribblenauts and Spore not only give you freedom get to a goal however you want, but they let you share your ideas with the world. In Scribblenauts, you get to type anything into the Nintendo D.S. and have them appear in game for use. In Spore, you create a species and help it evolve however you want it to. Most games today allow you to create your own levels and share them with others. Only thing about having all of these features is kids really don’t want to stop playing. This leads to the antisocial “con” of video games.

Some think that video games are socially isolating. The only socially isolating scenario I can think of is spending hours in a closet playing Pac-Man or Galaga. Playing the same games in an arcade can result in the exact opposite effect. People in an arcade can start up a conversation about their records and short-cuts in H2Overdrive (a boat racing game). Even playing single player games at home can become socially interactive by using forums and other conversational tools on the internet to talk with others. Playing online multiplayer games force players to get into their opponents thoughts. Video games allow people around the world to compete with each other for highscores and virual fame. Competitive behavior makes us want to be better than others, so people start to discuss strategies with others to make the competition tougher. Video games are actually pretty high on the list of socially active activities.

Tetris on the Brain; Original photo by daveknapik; modified by Jack

Not only is there evidence against every video game myth out there, but there are also studies that prove that video games are good for you. For example, a study was done in Albuquerque by the Mind Research Network that tested the effects of Tetris on a person’s brain. Simply playing Tetris for 30 minutes a day for three months thickened certain areas of the participant’s cortex and increased brain efficiency. MRIs compared the brains of the girls who played Tetris to the control group that didn’t. These MRIs showed thicker cortex in the areas that scientists believe the brain uses to plan complex and coordinated movement, and in the areas that are believed to be used for multisensory integration. This part of the brain organizes the five senses into one understandable and useful arrangement for the brain. Other MRI scans showed that brain efficiency was increased in areas that are often associated with critical thinking, reasoning, language, and processing. It’s unknown whether or not the brain returns back to its original state after not playing the game for an extended amount of time. Based on other brain studies, we can hypothesize that, “Use it or lose it.” For those who haven’t seen how intense tetris can get, I have included a video below.

If all reaction and planning games help the brain develop thicker cortex and increased efficiency, playing this game daily for an extended period of time should cause your general times for answering the questions to decrease. Even if the game isn’t as effective as Tetris, and short time effects aren’t known, it may still show some results. I just hope you know your division. Being that as a human race, there is still so much about our own brains that we don’t understand; it’s possible that training certain parts of the brain may not help its use in other activities. Studies are being done on whether or not certain effects from video games to the brain can have some real world uses. Daphne Bavelier and her team found that gamers can easily sift through unnecessary visual information. The gained skills can last for months or years. The obvious visual advantages have real world applications, like driving. Playing video games can also stop some of the effects of aging on your vision.

Specific skills are gained from accomplishing certain tasks. The effects of playing games that force you to accomplish multiple tasks at once, like first person shooters, can be completely different than games that isolate the tasks, like puzzle games. The simplest argument for video games is the fact that just using your brain helps it make connections, so playing video games is better for your brain than just sitting around watching a cartoon. Playing complex video games can help in many areas of your life, but even though they are fun, learning a language or playing a sport might have a similar effect.

What were your scores (the change in time, your initial time, and your post-game time) in the game? Based on evidence, should the game and other games in general help your brain make certain connections?

The capacity of the brain to learn and change is known as Plasticity, and it relates a lot to how video games can create and train mental connections. Are there any other activities that change brain Plasticity? If so, what are their effects?  Is there evidence that certain genres of video games are better than other genres at training the brain?

Photo by Denn

When I hear dishonesty I think of lying. It turns out that other animals besides humans can lie, too. When I hear that, I think no way, but scientists from Australia have found out that there is dishonesty in the animal kingdom. The dishonest animal is only two centimeters across, the fiddler crab.

The fiddler crab has one giant claw which it uses to attract mates and fight rivaling males. If the big claw is lost it can always grow a new claw. This is where the lying comes in. During the growth of the claw, the crab’s body says there is a “cheaper” way. They make the claw bigger but they also make it lightweight and toothless. Dr Simon Lailvaux of the University of New South Wales says that the interesting thing is that other males can’t tell them apart. Before a fight the crabs display their big claws which is important to the process.

The study is important because it helps us understand more about dishonesty among animals. The thing is it is hard to pick up on it. It is hard because dishonest signals are supposed to be hard to catch on to. Lailvaux said “By studying how animals fight we can learn what physiological and performance capacities enable males to win fights, we’re getting closer to identifying which traits are likely to be generally important for male combat.”

Can these crabs lose their claw multiple times and if so do they get weaker each time? Are there other animals that can bluff in a similar way as the fiddler crab? How are fiddler crabs able to re-grow their claws?  Can this be used to help humans?

Nudibranch (Chromodoris kuniei) photo by Doug.Deep

In honor of our invertebrate lab and exploration of the animal kingdom, I’d like to invite you to hunt for some interesting invertebrate videos on the web.  I could really use videos for the following phyla:

• Nematoda
• Platyhelminthes
• Annelida
• Mollusca

But, any phylum will do.  Post a link to the video here and include in your comment information about the video, what phylum the organism in the video belongs to, and defining characteristics about the organism that determines its classification into that phylum.  Have fun!

Specimen A

Specimen B

Specimen C

Specimen D

Specimen E

Specimen F

Specimen G

Specimen H

Specimen I

Specimen J

Chris shows us one way to examine a fossil.

Below are the results from one group (Sam, Mike S, Jack, and Alec).   Now, let’s debate!  What information do you disagree with?  How was your cladogram different/better?  What characteristics did you identify and how did you explain them?  In your comments, use research-based explanations with links to your evidence!

Ancestors of D, E, I, and J were seperated from the ancestors of A, B, C, F, G, and H because of an earthquake.  After several generations, the ancestors of D, E, I, and J developed holes because they needed a way to filter water to eat.  Habitat isolation led to these two groups developing new traits to the point where they were no longer able to mate with one another.

Competition for food between D, E, I, and J was really high.  Ancestors of species I developed joints so it could walk out of the water to find a new food source.  Because species I was symmetrical, it was caught by prey easily.  As a result, I became less and less symmetrical so it would not be caught by predators as easily.

Ancestors of species D were pulled by strong currents into an attractive fishing area.  They were seperated from their common ancestor between J and E.  Fisherman were able to harpoon ancestors of D.  Species D became transparent over time to avoid being caught.

The ancestors of E and the ancestors of J began to mate only with those like them, eventually causing them to be too different to mate.  This caused visible differences.

The ancestors of species A were the only ones that were moved by a growing mountain into a place where motion was still unecessary.  The other species grew joints to leave the water for protection against predators.

The ancestors of species b and g found the presence of symmetrly disgusting and only mated with those who are less symmetrical.  The ancestors of H, F, and C only liked those that had symmetry.  This eventually led to a split in species.

A group of the ancestors of species B traveled to a forest.  This species became transparent to hunt smaller organisms without being seen.

A rare event caused the bulk of the F, H, and C species to be split into three groups when an island was splint in a volcanic event.  By the time the volcano stopped erupting, species F, H, and C were no longer able to mate.