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Miss Baker's Biology Class Wiki
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9th Honors Biology
Science Online '09
Each group must post all of their research in the appropriate space below and
hyperlink the sources
next to each piece of information. It is not necessary to include skits or extensive detail. An overview of the main points in your topic and an overview of your example will suffice.
A list of sources is NOT allowed.
List group members before you begin posting.
Remember, you should copy and paste from Word.
Do NOT type your information directly onto this page.
Alan Crotzer case
is an example of how DNA testing can be used in order to enhance the crime scene investigation career. Evolution is a change in alleles through generations, and that is what makes everyone's DNA different. If a DNA sample from the crime scene is recovered, it can be tested and compared to another DNA sample from a suspect. If the two sample match, that puts the suspect at the scene of the crime. Without understand evolution, this advancement in technology probably wouldn't have occured.
The way they are able to test DNA samples is through a process called
. This process works using a slab of gel with small holes in the negative end of it. After the DNA goes through Restriction Fragment Length Polymorphism (a process that prepares the DNA samples using enzymes), it is inserted into the tiny holes in the gel. Because DNA has a negative charge, it stretches to the positive end of the electrophoresis machine, revealing a sequence of bands. Next, the bands can be compared and if the crime scene sample matches to one of the suspects, the culprit is then discovered!
of gel electrophoresis results:
Gel electrophoresis is a procedure for separating a mixture of molecules through a stationary material (gel) in an electrical field.
An example of how Gel Electrophoresis is used today is through Paternity tests. Since everyone has their own specific DNA and not one person has the same DNA it makes everyone unique. The only time your DNA will be similar to anyone else’s’ DNA is if that person is your twin or your father or mother. Because your Father and Mother have similar DNA as you do it makes it easy for scientists to find a correct father if two men claim to be the father. They simply use Gel Electrophoresis with the DNA samples from the alleged father and the child and whichever alleged father has similar DNA will ultimately be the biological father.
The information above is not entered correctly - Miss Baker
Mary Claire Shurina
Evolution shows up a lot in a crime scene. Specifically, through testing DNA in a machine called a gel electrophoresis machine. When using this machine, a person will place suspect DNA in each compartment of the machine into the agarose gel of the machine. DNA being negative in nature, will be attracted to the positive side of the machine. The bigger pieces of DNA will not reach the positive side as quickly as the smaller pieces of DNA. So how can this relate to evolution?
Every human has genetic variations because of mutations. No two people on the earth will have the exact same genetic sequence unless there are identical twins.
Andy Pease, Mark Yeon, Amanda Smith
-DNA fingerprinting is a method used by forensic scientists to determine whether the DNA found at a crime scene came from a particular individual.
-Humans are 99.9% genetically identical, but still differ at about 3 million base pairs. No two people on Earth have the exact same genetic sequence, or DNA fingerprint.
-Since the invention of this method, DNA evidence has exonerated more than 150 wrongly convicted people.
What does evolution have to do with solving crimes?
This method only works because evolution does. The human genome (all the genetic information an organism carries) is constantly evolving with each generation. It is the variation caused by evolution that forensic scientists use to help solve crimes.
After 12 years in prison, Christopher Ochoa was released in 2000. This was due to DNA fingerprinting, a test used to match crime scene DNA to the DNA of a suspect. The DNA test performed by University of Wisconsin students and professors proved that Ochoa was innocent of a 1988 murder in Austin, Texas for which he had been wrongly accused.
Here is an
that explains the process of gel electrophoresis.
This picture shows gel electrophoresis, the technique used to to match DNA to a suspect.
This is an example of the bands of DNA made by using gel electrophoresis. Suspect 2 comitted the crime because his bands of DNA match those found at the crime scene.
This picture shows paternity testing, another method of DNA fingerprinting.
Evolution is very prevalent in today’s agriculture. Evolution is shown in its simplest form through the process of natural selection.
really helped us toward illustrating our point. Our example tells how some potato beetles are resistant to the pesticide Bt. When the pesticide is sprayed and the non-resistant die, leaving the resistant beetles alive and allowing them to reproduce making the entire population resistant.
The method of refugia allows both resistant and non-resistant beetles to live by not spraying a certain area of the crops. Thus, continuing this cycle and protecting the majority of the crops.
Evolution affects today’s agriculture many ways including economy and food supply. If a crop does not do well, the revenue for the crop does not do well either. If a society depends heavily on one crop and that crop does poorly due to natural selection then that society’s food supply with suffer and a famine can occur.
Which is our example, the Irish Potato famine. The problem was that the Irish farmers were planting an inexpensive type of potato call the “lumper” potato. This was the only type they were planting, therefore there was no diversity and all the lumpers were essentially clones of eachother.
The lumpers got infected with a fungus called potato blight. This fungus tunrs the potatoes in a slimy mush and makes them unedible. The blight killed almost 100% of the crop within the second year. This lead to the famine that killed 1/8 of all the population of
If diversity had existed on their farms, the other types of potatoes may not have been affected by the blight and the population would have other food sources still. We found all this information out
. The diagram should help the explain the need of diversity in crops.
When evolution occours in the wild it is called natural selection, but in some cases it is caused by artificial selection. The example we used was the Maize Chlorotic Dwarf Virus, which is found in corn. This virus limits the growth of the plant and decreases its productivity, which means the plant that is infected wont supply as much food as one that is healthy. This virus can greatly affect the productivity of a farm and can reduce the food supply.
So in order to find a solution to the problem scientist used artificial selection. They found a close relative of corn, the teosinte plant, this plant carries gemes that make it immune to the maize chlorotic dwarf virus along with six other diseases that affect corn. Scientists then used the genes of the teosinte plant and made a breed of corn that is resistant to the virus.
Potatoes are not originally from Ireland; they actually came from South America, where the natives had artificially selected the potato they could use. Before the potatoes were introduced there was a severe hunger problem, so they planted potatoes, specifically “lumpers,” which have little genetic variation. This new crop helped for a while, until the environment changed. Our example was the Potato Famine in Ireland. The potatoes became a revolting goo.This started in 1845 and lasted for six years.Since the Irish were dependent on this potato, they met devastation.
One in every eight people
died of starvation. Even if a uniform crop is cheaper
its benefits do not last too long.
Genealogy is the study of your family history.
It shows important facts about your ancestors.
From genealogy you can make a family tree.
Most family trees show the place of birth, birth date, and death date of a person.
Evolution is the change in allele frequency over time.
It is a gradual process in which a species changes and the change is usually into a better or more complex form.
From learning about DNA scientists have found that all human DNA is 99.9% the same to every other human.
Based on this we can follow migration patterns and see where DNA might have mutated.
Eventually they reach a point in which you see a common DNA sequence.
This sequence traces us all back to common ancestors in Africa.
In other words if you start with the first person’s DNA and follow where their offspring went you can see what mutations were made over time in order to survive better in the specific environment they were in.
Eventually you will reach humans living today.
Due to this we can tell evolution has taken place because evolution is the change in allele frequency over time and that is exactly what has happened with the mutations.
We have two types of DNA: mitochondrial (mtDNA) and nucleus (DNA)
Nucleus DNA comes from both parents where mtDNA only comes from the mother.
clip to see why.
Due to this we can trace back your DNA from a single lineage (you to your mother to your grandmother to your great grandmother…)
Over time everyone’s mtDNA will show a common ancestor that scientists call Mitochondrial Eve
Due to this scientists are willing to agree with in reason to what the Bible says about all humans coming from Eve
BRYANT, WILL, AND KT’s GROUP
(see links below for navigation)
<Genealogy and Evolution (and you)>__
Genealogy- is an account of the descent of a person, family, or group from an ancestor or from older forms.(
Through evolution, we can track, and acquire some idea of where our ancestors are from. Obviously, in today’s society, finding your lineage is important, whether you’re a son wanting to know who your father is, or an eighty year old lady wanting to know where your ancestors are from. Genealogy, however, has more to do with the eighty year old lady style.
There are two ways one can find their ancestry; Mitochondrial DNA, or Y-Chromosome DNA. In this summary, we’ll be looking at the Mitochondrial DNA (MtDNA). MtDNA is obviously found ion the Mitochondria. It’s said that mitochondria once were a separate organism, before our ancestor cells absorbed them, which provides a sufficient explanation of how there’s even DNA in our mitochondria in the first place, which is our cell’s energy providing organelle. This DNA however, is maternally acquired, which means it’s only passed on with women. Men do have this MtDNA, but they cannot pass it on to their offspring, only the mom can. So, based off the hypothesis that we all came from Africa originally, it would make sense that after certain groups migrated outward, their specific MtDNA made specific mutations. These mutations differed according to the certain groups of people, in an organized matter. So lets say for example, the people that migrated to Asia first had acquired a small mutation in an area of the MtDNA. Well, we know that because Asian’s ancestors have that specific mutation, then if you have that change in your MtDNA, then your ancestors must be from Asia. This leads to a very controversial topic in science, first aroused by three scientists, who did a study on the matter for the
scientist journal, Rebecca Cann, Mark Stoneking and Allan Wilson; the topic of mitochondrial “Eve”.
Much unlike the Biblical connotation, this Mitochondrial “Eve” was not the mother of all life, she’s just everyone’s most recent common ancestor. She’s not someone sitting in some museum in London or something, but a hypothetical figure of ancestry. Of course, there were other women around, but all of their kids either died, or all of their kids were men, thus not passing on the gene.
So if you were in Miss. Baker’s 5th period class, you saw how people go in everyday to these geneticist labs, and can get their MtDNA matched to a specific “ethnic” group’s MtDNA, and find what group of people they’re most closely related to. So, if you were in Miss Baker’s 5th period Biology class, you also say a common urban myth proved wrong also. According to MtDNA, we are not related to Neanderthals, or what we like to call cavemen, which was a bit of a disappointment to many scientists. A lot of times, when we think of British people, we think of messed up teeth, and the caveman like structures that British people seem to more commonly carry than other people. This would lead us to believe that Neanderthals started in the North, and then migrated south, and then change took place over time, thus creating the common human. True enough, us and Neanderthals have a common ancestor, but because our MtDNA is all equally different, and there’s no specific point where it’s more like the Neolithic MtDNA in a group’s MtDNA, and then where it gradually mutates. Thus, it’s hypothesized that we’re simply not related to Neanderthals.
There are however many downsides to this testing. For one, it’s not certain that the MTDNA will be inherited by only the mother. Mutations could occur, to whereas the Father’s MtDNA is read rather than the Mother’s, thus throwing the whole idea off. There are also limited sample bases with which your MtDNA is compared, so the results might not be so exact. This would prove to lead to be the cause for it being unlikely to identify your exact results, because it’s very difficult to find every specific group of people in the world, and their own specific record of MtDNA.
Thanks to evolution, this theory is true. The idea that mutations occur over time, this just backs up the fact that over time, certain individuals acquired certain mutations, specific to that group of people. It’s almost like Natural Selection, without the competition. Also, the idea of all humans on earth having a common ancestor helps also, because from there, we can figure out that because our MtDNA is acquiring mutations over time, this alludes to how our MtDNA could go in the reverse way, from really mutated to untouched. This would be the basis of which we say that there has to be a mitochondrial “Eve” out there. Evolution has EVERYTHING to with Genealogy. Without Evolution, Genealogy cannot exist.
is obviously where we got all of our information, but it also covers the ideas above in a more detailed explanation. This is EXCELLENT information, and being PBS, it’s very reliable, and well cited. Even from here, there are still problems that can arise, but hey, the scientists are trying really hard as it is. Now, at least we can have a very good guess as to where we are from, and who our ancestors actually are, all thanks to the one theory of Evolution. So when you get to be eighty, and you want to add some meaning to your life by finding out who your ancestors were, thank Evolution, your genealogic buddy-friend!
Viruses reproduce and evolve very rapidly and therefore are difficult to find cures for. Medical science gains more and more advantages all the time. New treatments and medicines are introduced to us because organisms that cause disease are always evolving. When we can understand evolution, it becomes much easier to figure out the causes of the disease and find a cure.
Our bodies are confronted with different bacteria and viruses all the time, and constantly work to defend themselves against them. However, since they evolve so quickly, there are several different strains of the same virus or bacteria and our body can’t defend itself from all of them. Many of the traits that make us feel sick during an infection are actually pathogenic adaptations — characteristics favored by natural selection that help these germs reproduce and spread.
The flu is one of the pathogens that our bodies are working against.
The virus is spread by tiny droplets that are released into the air when people sneeze or cough. Symptoms include: fever higher than 100 degrees, headache, tiredness, chest pain, and runny nose. You can avoid getting the flu by taking these
getting your flu shot annually (or the
for those who would prefer not to use a needle), helps too!
There are many different strains of the flu, which is why it is so hard to find a single cure or vaccine to prevent it.
When a vaccine is made to prevent one strain, that strain quickly evolves to be resistant to the vaccine, and the vaccine does not work as well. Because the flu evolves so fast, a new vaccine has to be made every year or else it won’t be effective. When a vaccine is made to prevent one strain, that strain quickly evolves to be resistant to the vaccine, and the vaccine does not work as well.
Evolution is most prevalent in medicine when it comes to mutating bacteria that become antibiotic-resistant. When bacteria reproduce, they copy their DNA and then split in half. Sometimes, it is copied incorrectly and a mutation occurs. This causes genetic variation in the bacteria population. When a person takes antibiotics to kill the bacteria, some bacteria traits will allow certain bacteria to better survive exposure to the antibiotics. If someone stops taking antibiotics before they are supposed to, there aren’t enough to kill all of the bacteria, and only those without the advantageous trait are killed. This leaves behind bacteria with the trait that allows them to survive exposure to the antibiotic, and they reproduce others with the same trait. Since antibiotics put selective pressure on the bacteria, doctors should only prescribe antibiotics when absolutely necessary.
An example of this is tuberculosis, an infection of the organs, usually the lungs. Recently, there have been outbreaks of antibiotic resistant tuberculosis, and there are few antibiotics which the bacteria aren’t resistant to. This is a huge problem in areas where these medications are not available, and cases in such areas often result in death. This shows that it is absolutely vital for medical professionals to be fully knowledgeable when it comes to evolution and genetic mutations. By understanding that antibiotics put selective pressure on bacteria, doctors will prescribe them only when it is necessary.
The hairy nosed wombat is a type of wombat that is distinguished because of the short, soft hairs on its nose. It can grow up to 40 inches long, and weigh up to 88 pounds. They are usually brown, black, or silver grey, and its ears are longer that the common wombat. There are two types of the hairy nosed wombat, the northern, and the southern. The northern wombats are usually bigger and have more color variation than that of the southern type.
The northern wombats are now critically endangered and are some of the arrest animals in the world. There is only one small population of them in the world, and they are located in
. They are kept in a fenced environment to keep dingo’s out, which wiped out 10% of their population.
Based on the evolutionary theory, small populations face two factors that can make conserving them more difficult: Inbreeding depression and low genetic variation.
When there is a small population of animals, mating occurs more commonly among relatives. Since the recessive traits are still there, when you have a smaller population there is a greater chance that the recessive deleterious allele will be expressed in the offspring since it got the deleterious allele from both the father and the mother.
A population could not evolve in response to environmental factors if there was no genetic variation. For example, a population that is exposed to a certain disease will have the animals with genes that resist the disease selected naturally so some of the population will survive. However, with no genetic variation in the small population, if there is no gene present that resists the disease then the population will be wiped out since no animals will be able to survive.
Most times when populations are low, it seems as though it is a good idea to put wild populations in with hatchery raised fish. This however can cause the fish to form new gene variants that they will introduce into the wild fish populations once they are set back into the wild.
At the University of Washington a study was done that showed that salmon that were raised in the wild had different spawning dates from hatchery-raised salmon. When they are introduced back into the wild these salmon could potentially pass this trait on to the wild population. Spawning at an earlier time, as the hatchery raised salmon do, could prove a disadvantageous trait because of the environmental factors.
-A low genetic variation in a population of organism is the overall cause of a weakened population
-Genetic variation is the variation of alleles in certain organisms of the same species.
-A low population (whether created from human destruction or natural destruction) would result in low genetic variation because of inbreeding
Inbreeding is when animals that are closely related to each other mate
-When animals do this the offspring have a much higher chance of getting the parents traits, whether they be good or bad
After much inbreeding in a small population, organisms might start to show bad recessive traits that were there previously, but not noticeable
These recessive traits may consist of disease, or other weaknesses that would hinder the organism’s ability to survive and reproduce
-This presents us conservationists with the task of reintroducing other organisms of the same species to increase the Genetic Variation, resulting in a stronger population with less disease
Overview of example
We used the black-footed ferret as our example. Almost all of its habbitat has been destroyed, leaving only a small population left. This small poulation suffers from inbreeding depression and would have become extinct if conservationists hadn't introduced strong healthy captive ferrets to breed with the wild ferrets to add more genetic variation to the population.
conservation with genetic variation and inbreeding depression
If a population is becoming endangered and too small, this leads to inbreeding (mating with relatives)
Relatives will most likely carry the same recessive alleles that are bad for members of the population, and will pass them on to offspring; this means there will be a very low genetic variation
Without this genetic variation, they cannot evolve with a changing environment!!
conservation and natural/artificial selection
Wild populations, by natural selection, have genes that are good for survival and reproduction in the wild, but captive bred populations have genes good for captivity survival and reproduction by artificial selection
If they mate or are exposed to each other, the captive population will pass on genes that are not good for survival in the wild
conservation and phylogenetics
Phylogenetics is the evolutionary history of an organism (how much evolutionary change has occurred)
Knowing about it helps conservationists calculate a conservation value, or currency, for each ecosystem
The currency provides a measure of the ecosystem’s biodiversity; the higher the currency, the more it should be considered for saving
A population of 40
or adders, suffered from inbreeding depression due to Swedish farming activities isolating them from the other adder populations. These Swedish adders carried a recessive allele that caused stillborn and deformities. When the adders in this small population were forced to mate with each other, two copies of this recessive allele would be inherited, so it would be expressed. The answer of course was to perform out breeding by introducing adders from other populations to this one. They would mate with each other instead of with relatives, bringing them out of their inbreeding depression and allowing for more genetic variation. Since the conservationists knew about evolution, they knew this could be done to save the population.
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