Darwin’s Voyage

1. what was the original purpose of Darwin’s voyage on the H.M.S. Beagle, and what was the ultimate significance of the Voyage? The original purpose of Darwin’s voyage was to learn and discover more about biology and to gain insight on plant and animal species. The stated intent of the voyage was to obtain evidence that supported the biblical theory of creation as well as chart poorly known parts of the South American coastline.

2. Why does the Antibiotic resistance problem represent an example of evolution? The antibiotic problem is a perfect example of evolution because it shows how species have adapted and evolved based on their environment. It shows how bacteria can adjust and either thrive or die when faced with an antibody. The weak bacteria dies off and the strong bacteria survive and In turn multiply a stronger bacteria.

3. using the material covered in this lesson, and your own research, describe how the work of Charles Lyell impacted the development of Charles Darwin’s theory of evolution. Include the major work done by Lyell and what it led Darwin to consider.

Charles Lyell was a geologist and paleontologist who wrote Principles of Geography which greatly influenced Darwin. Lyell’s theories emphasized natural law. To Lyell it made sense that geological processes were much the same today as they were thousands of years prior. Forces such as, volcanic eruptions, erosion by rivers, wind and rain, and sedimentation in rivers and lakes. The term uniformitarianism, the assumption that forces from the past are similar to the ones we see today.

Darwin read Lyell’s Principles of Geology and greatly influenced Darwin. Lyell showed how small and minuscule change over immense periods of time could produce large changes.

While on the beagle, Darwin discovered this first hand with different species he collected that their were different adaptations of species from different coasts and ecosystems. He also began to believe the earth was more that just 6000 years old. He also noticed signs of geological change, such as a section of shoreline that had been lifted due to an earth quake.

Without having read Charles Lyell’s documents, Darwin may have never looked more closely into the adaption of species and natural law. Darwin had the opportunity to witness all of these forces, and during the voyage he became convinced that all Lyell’s views were correct. Thanks to Lyell, Darwin was able to collect information and see fist hand while on his Voyage the affects of natural law and help him on his way to develop the theory of evolution.

Lesson 2

4. What role does natural variation play in the process of natural selection and ultimately, evolution? Without natural variation, no trait could be selected for or against one another. Therefore, there would be no way for evolution to happen. Natural variation is everything from different sizes and shapes, behavior, physiology, and reproductive abilities. These differences, no matter how small potentially affect an individual’s survival and reproductive success. Without natural selection the change in allelic frequencies in a population over time would not be able to happen.

5. Give three lines of evidence that Darwin used to support his theory of evolution by natural selection, and briefly explain how each one provided support. There are 6 different types of evidence that Darwin used to support his theory. The three I will focus on are fossils, comparative embryology and artificial selection. Firstly, Darwin found that fossils of ancient organisms are a lot simpler than present day organisms. Sequences of fossils show that there is a gradual series of changes over time, and get more complex. By studying a series of fossils, Darwin was able to see how organisms gradually changed over time due to natural selection.

Secondly there is comparative embryology, which is the study of the early development of a fertilized egg. Darwin was able to see how very similar the embryos are at an early age. An example is fish, turtles, humans and mice all develop tails and gill arches early in their development even though only few maintain this structure as an adult. This helped Darwin realize how all species could have shared ancestors.

Lastly is artificial selection, which was one of the main pieces of evidence that Darwin used to identify his theory on evolution. Darwin studied and showed how the selective breeding of crops and animals led to highly specialized varieties with unique traits. By studying this he was able to see first hand how evolution can occur by artificial selection. An example would be the Great Dane. Thousands of years ago, the Great Dane was a medium sized breed, but due to artificial selection, humans were able to create a large breed of Great Dane.

6. Imagine you are a farmer researching the impact of GMFs. What is one advantage and one disadvantage that would be relevant to your work? Explain each. GMFs is a very controversial topic and can be argued both ways, good and bad. If I were a farmer, one of my advantages would be cold tolerance. Due to our ever-changing climate it is becoming increasingly hard to produce a consistent and healthy crop. Though scientists have introduced a gene form cold water fish, that helps prevent freezing and makes crops resistant to cold spells. This would be a great advantage for farmers to ensure that they can produce a healthy crop, no matter what climate types may be thrown their way.

Though a disadvantage of GMFs would be allergenicity. If I were a farmer and used GMFs to create a cold tolerance, then I could be at risk for allerginicity. An example would be the cold-water fish genes that I am using for my crop. If this gene is inserted into my tomatoes, then they now can be dangerous for people who are allergic to fish, and now allergic to my tomatoes.

7. Explain how natural selection could have produced the modern long necked giraffe from short-necked ancestors? Due to natural selection and Darwin’s 3 conditions, long neck giraffes could have been produced from shorter necked ancestors for the following reasons. The ones with longer necks could have more easily reached the leaves at the top of trees, therefore getting better nutrition than those with the shorter necks. The fitter Giraffes (with longer necks) then reproduce and carry the longer neck gene. Over thousands of years this could be the reason the long neck giraffe is what it is today. It would be partly due to Descent with modification of a longer neck.

Lesson 3

8. Explain how genetic drift can lead to a reduction in the genetic variation within a population? A) Genetic variation is the variation in the form of each gene and genetic drift are the changes In allele frequency in populations. Genetic drift usually is most present in small populations, where infrequent alleles are at more of a risk of being lost. Once this pattern begins, genetic drift will continue until the rare alleles either get lost by a population. This causes a decrease in genetic diversity within a population. A lack of genetic diversity then leads to a reduction in the forms of each gene that is being passed down, therefore reducing genetic variation. b) Drifts are most likely to occur slowly over many generations. But when population sizes are small, the chance for drift to occur is much higher.

Endangered species are another type of population that gets hit by genetic drift c) The example of migrating birds best represents the bottleneck effect for the following reasons; bottlenecks occur when a population is drastically lowered due to death or reproduction problems. Secondly the three birds that’s survived and reproduced can only carry so many alleles, And with such a small amount of birds only reproducing with each other there is a strong chance that many of the alleles in the population would be lost. 9. Describe the relationship between mutations, genetic variation, natural selection and evolution. Your description should include what a mutation is, which type of cells mutations must occur in to increase genetic variation and how variation is required for natural selection.

Genetic variation can change in a population by a result of the four mechanisms, which are mutation, migration, genetic drift and selection.
Mutation is the only one that actually introduces genetic variation into a population. Mutations are the random changes In the genetic code. They are the only way to get new alleles. The only mutation that affects evolution is the gametes ( sperm and egg cells) which are the ones that become part of the gene pool. Without these mutations, there would be no genetic variation, thus leaving us with no differences in populations. Without differences in population there would be no natural selection. Evolution would not be possible without all the steps present. Without genetic variation, the frequency of alleles would not change.

10. Explain how natural selection and sexual selection can work together to cause the evolution of antlers on male moose. Natural selection and sexual selection can either work together or against each other when it comes to different populations. For the male moose, these selections work together. For sexual selection, the antlers provide an appeal for the female. Since females are generally drawn to physicality’s the large antlers are the perfect sexual selection. Though, the antlers also provide a weapon for the male. He can use his antlers to fight off enemies. Protecting him from being killed. This makes the male moose a strong and fit individual for natural selection, as he would have a harder time being killed or removed. This explains how the male moose has advantages for both sexual and natural selection.

11. Suggest two ways a synthetic biologist can change the course of evolution.

The first way synthetic biologists can change the course of evolution is by treating and curing illness. There was an ecoli capable of detecting diseases in humans by lightning up green when the encountered chemicals related to specific diseases. This could change evolution by making things like cancer treatable. In time, all illness and disease could be cured with synthetic designer genes. Secondly, synthetic biology could change the course of evolution by fixing environmental problems that could otherwise be wiped out by evolution in 1000’s of years. Geneticists learned how to isolate a gene for breaking down PCBs from the bacteria and then inserting it in other organisms that can survive different soils and climate types. With this we can solve environmental problems and keep things like water and soil clean.

Lesson 4

12. a) Temporal
b) Hybrid Sterility
c) Mechanical
d) Geographical
e) Behavioral

13. Describe the steps necessary for geographical isolation to lead to speciation.

Geographical isolation happens because of a physical barrier between populations and speciation occurs when enough genetic differences build up between two populations that the populations can no longer interbreed successfully. So for geographical isolation to lead to speciation you would first need to separate a population. An example of this would be grasslands. Animals graze over a central portion of land until is becomes desert. The gap then prevents grasses reproducing with the grass on the opposite side of the desert.

The second stage that would need to happen for speciation to occur is some sort of natural disaster on one side of the desert, such as an oil spill. This causes the one side of the grasslands to develop a stronger gene and higher tolerance for the oil and toxins. Lastly, there would need to be a reconnecting of the grasses on each side of the desert. That way the grasses then can interbreed and develop hybrid grasses that cannot reproduce. This creates a barrier of gene flow that keeps both grass population distinct.

14. How might the increasing isolation of populations in these forests influence their evolution? a) The populations within each smaller forest may have to adapt to different environmental conditions, therefore developing different genetic makeups over time. This could be an example of habitat isolation, like we see with the scarlet oak and black oak trees. Populations may evolve in response to different selection pressures as well. This changes the evolution of certain species over time. b) The fragmentation of forest would affect the evolution of a large mammal like the moose more so than a small invertebrate like a worm for the following reasons; a moose is a large animal with specific mating rituals, if moose are separated into several smaller forests, it will be harder to find a mate and produce offspring.

Secondly, moose don’t reproduce in large quantities and it is harder for them to produce offspring than the worm. Thirdly disturbances and smaller forests lead to smaller foraging territories, smaller populations and less variation within gene pools. Worms however are less influenced by fragmentation because they are small with a short life span, and can live off little land and disperse easily if needed.

15. Identify and explain the type of natural selection that accounts for the evolution of the hollow bones of birds, which makes flight possible.

The type of natural selection that occurs here is directional selection. The lighter the bones, the lighter the bird will be and will be better able to adapt. So ultimately, natural selection will just keep selecting the fittest birds with the lighter bones from every generation. The birds that cannot fly as well or the heavier birds that are less fit will die off because of natural selection. This is how; over time the bones of birds have evolved to become very light.