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BIOL 1001 Chapter : CH 1 OUTLINE Finished

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azuremammoth471
15 Mar 2019
School
LSU
Department
Biological Sciences
Course
BIOL 1001
Professor
All

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Document Summary

Many of the places that we will study as we move across basically about half of the world are less economically well off then most of us in the us are. Which sometimes makes it easy to jump to the conclusion that we are lucky or that they are unlucky. We"re going to try to make things a little richer and more complicated than that. We"re going to try this semester to understand: how things are, the way things are, where they are, and why things are the way they are, how did they get that way, why is it like that over there. We"re going to try to understand how people have adapted to their circumstances, adapted to their reality over time. We"re going to try to understand through their eyes; the decisions they"ve made about their lives which might be very different from the decisions we make about our lives.

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Related Questions

Question 1

Evolutionary algorithms are used:

In engineering, to arrive at solutions by going through many permutations of possible solutions and allowing them to evolve.
A genetic feature of complex organisms.
A process undergone by the human brain, which is similar to evolution by natural selection.
Another term used for a computer algorithm in general.

Question 2

Human literature and languages can be studied using methods similar to those used for constructing phylogenies because:

There is no other way of studying these things.
Languages evolve roughly along the lines of species, with mutations (changes in words and pronunciation), descent with modification (languages becoming more different along the way), and branching of languages (languages giving rise to other languages that are similar to them).
Because literature and languages are constructed by organisms (human beings), so what applies to one must apply to the other.
Languages undergo a process of word swapping, which is analogous to horizontal gene transfer.

Question 3

The degree to which horizontal gene transfer occurs in eukaryotes is:

Something upon which the entire validity of evolutionary biology hinges.
A mystery that may or may not disprove evolution, but we simply don't know enough about it at this point.
Something that would overthrow the notion that this phenomenon is important in bacteria.
An interesting and potentially important aspect of biology with relevance for how evolution occurs, but not something that would call it into question one way or the other.

Question 4

Learning about the history of scientific theories and the reasons for why they are initially accepted or rejected is important mostly because:

It makes for exciting story telling, and this is very much needed to get people interested in science.
It teaches us about the process of science as it actually occurs, which is somewhat different to the idealized notion of a purely objective undertaking.
It tells us which theories are definitely true or false.
It tells us that science is actually a totally subjective process that tries to present itself as objective. In reality, personal subjective factors are the only relevant factors that really matter in science.

For years we have been able to analyze the fossils of extincthumans like those of Neanderthals. Their bones gave us clues to howthey looked, how they lived, and how they might be related to us.In the last few years, we have been able to get a better view intothese extinct species and their relationship to our species. Thanksto next generation genomic sequencing technologies, we have beenable to obtain genetic data on Neanderthals, Denisovans and othersthat have allowed us to make direct comparisons between our speciesand theirs. In addition, we have been able to observe the presenceof DNA from these extinct species within our own genomes which tellus that we had kids with these now extinct humans.

If we take Neanderthal DNA as an example, we find that we share99.5 percent of our DNA with them. Which means that we andNeanderthals were separated from each other for more than 500,000years. This also means that we were genetically similar enough tobe able to have offspring with each other. We see evidence of thisgenetic introgression between us and Neanderthals when we look atour DNA. Interestingly, if we obtain one thousand DNA samples fromGrossmont College students, we estimate that we would be able toextract at least 20% of the Neanderthal genome from them. Thismeans that 20% of our collective nucleotide sequences are sharedwith Neanderthals but this doesn’t mean that 20% of our genes areNeanderthal specific genes. Of the twenty-one thousand genes thatNeanderthals had, only a few dozen of their genes survive withinour genome. The same holds true for Denisovans. What is moreinteresting is that older versions of ourselves have a tendency tohave higher levels of DNA from extinct humans compared toourselves. In other words, over the course of thousands of years wehave been slowly weeding out the DNA of the other humans from ourgenome in favor of our genes.

One basic question that we might like to ask is why have we beenlosing Neanderthal and Denisovan genes over time? Also, why do westill have a significant amount of DNA segments that don’t seem tobe going anywhere? The answer to this has to do with selection.

The answer to the first part of the question has to do with thefact that we were not fully genetically compatible with the otherhuman species to begin with. Basically, to have had Neanderthal orDenisovan genes in the past meant that an individual's level offitness was reduced. To get rid of their genes in favor of our ownwould mean that the relative fitness of individuals would increaseovertime.

The answer to the second question has to do with the fact thatDNA segments from Neanderthals and Denisovans that did not code forproteins remained because there was little selective pressureagainst them. As far as genes are concerned, the only Neanderthaland Denisovan genes that remain only exist because they had aselective advantage or at least have been neutral to ourspecies.

DNA segments that that were neutral or that had a selectiveadvantage, whether genes or not, simply remained because they wereadvantages or there was little selective pressure against them.

Your task for this week is to look for information about oneNeanderthal or Denisovan gene that survive within our species andto tell me what function that gene has and how that gene mayincrease the fitness of modern human populations.

  • In your post, discussONE Neanderthal orDenisovan gene that is currently found within our species.
    • Tell us about the gene and its function. Explain what it doesfor us. (Make sure you give a citation.)
    • Explain in your own words any possible advantages that yourNeanderthal or Denisovan gene might have. Make sure you give ininformed opinion that is grounded in your research.

Part III – Just How “Identical” Are We?

Elise had been home from college for a week, and she was still preoccupied with Shannon’s diagnosis and her own potential risk for mental illness. Elise expressed her anxiety and concerns to her mother one night after dinner. “Elise,” her mother said, “your concerns are perfectly valid, and you have every reason to want to get more information. Why don’t we make you an appointment to consult with a psychiatrist?” Elise decided to make the appointment the next day. * * * * * Elise left Dr. O’Brien’s offi ce feeling that some of the weight had been lifted from her shoulders. On the car ride home, she thought about the things that Dr. O’Brien had said to her during their consultation. “It was good of you to come in to see me, Elise. You are absolutely right to have concerns for yourself when your identical twin has been diagnosed with schizophrenia. Research shows that schizophrenia is almost 50% heritable, and since you share nearly identical DNA with your sister, that puts you at a higher risk for developing this disease as well.” “Fifty percent may sound like a scary number, but remember that schizophrenia is a very complex disease, and 50% of what causes schizophrenia is due to things other than your DNA.” “Well, like what? What else could be contributing to Shannon’s schizophrenia that wouldn’t necessarily aff ect me?” Elise asked. Dr. O’Brien replied, “Th ere are many, many environmental infl uences that seem to play a role in the development of this disease, such as increased stresses and anxiety, or diffi cult relationships with other people. Interestingly, there is some groundbreaking research that is going on that suggests that the environment itself might even play a role at infl uencing one’s DNA at the molecular level. Th is concept is called epigenetics. An example of epigenetics in nature is the calico cat. Each calico cat has a unique orange and black fur color pattern because of alterations, called epigenetic changes, which occur within the cells that produce coat color during the cat’s development. Research in the fi eld of epigenetics suggests that individuals with schizophrenia appear to have some of these epigenetic changes to their DNA that are due to environmental infl uences, and that these alterations could be contributing to their development of mental illness.” “But wouldn’t I also have these ‘epigenetic alterations’ in my DNA?” Elise asked. “Not necessarily, because you and Shannon have not experienced completely identical environments throughout your lives. For example, you and Shannon have had diff erent teachers and jobs throughout high school. And I also understand that you spent many childhood summers with a friend and her family out in the Grand Canyon, while your sister was off at swim camps. If you are interested, I can give you some literature to read about this subject.” Elise was defi nitely interested. She took the articles and headed home.

1. Briefly describe what you know about the structure of DNA and how DNA is packaged in a cell.

2. At the molecular level, speculate on some ways that the environment might have an infl uence on DNA and its packaging