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Evolution: Understanding Natural and Artificial Selection, Study notes of Biology

Southern Maine Community CollegeBiology

A comprehensive exploration of evolution, focusing on both natural and artificial selection. It delves into the mechanisms of these processes, using examples such as the domestication of chickens and corn, the russian fox experiment, and the rock pocket mouse. The document also covers topics like taxonomy, phylogeny, and the history of life on earth. It further discusses the evolution of whales, the oxygen catastrophe, bacterial resistance, and human evolution.

Typology: Study notes

2022/2023

Uploaded on 02/17/2024

andy-kent
andy-kent 🇺🇸

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Lecture 1b: Evolution
Part 1. Evolution and Artificial Selection
Watch this instructional video on Evolution and Artificial Selection (4:59). Note:
Recent archeological evidence suggests that chickens have only been
domesticated for about 3,500 years, beginning with wild jungle fowl in southeast
Asia, though this is still being investigated. Corn (which was originally
domesticated by natives of southwestern Mexico), is thought to have been
cultivated for as long as 9,000 years. Then watch this short video (3:20) on the
Russian Fox Experiment. Answer the following question:
1. How does artificial selection lead to changes in populations over time? (50 word
minimum)
Artificial selection works the same as natural selection. Except artificial selection
is decided by human interference whereas natural selection is caused by nature.
Artificial selection requires a variation in population, and a trait that must be
heritable. This trait is selected by humans, and then passed down generationally
over time. Russian Fox experiment creator Dmitry Belyaev hypothesized that the
process of domestication was in part the result of changes in gene expression
patterns. Recent studies have shown that he was correct.
—-----------------------------------------------------------------
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Part 2. Evolution and Natural Selection
1. Watch the video on Evolution and Natural Selection (19:47), then answer
the following questions.
1. What are two observations and two inferences provided by Darwin and
Wallace to describe natural selection as a mechanism of evolution?
Variation exists among individuals in a population. More offspring are produced than
survive to reproduce. These two statements are observations. Individuals that are
better adapted to their environment will be more successful at reproducing. Differential
survival will lead to accumulation of traits more suited to the environment in the
population over time. These two statements are inferences.
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Lecture 1b: Evolution

Part 1. Evolution and Artificial Selection

Watch this instructional video on Evolution and Artificial Selection (4:59). Note: Recent archeological evidence suggests that chickens have only been domesticated for about 3,500 years, beginning with wild jungle fowl in southeast Asia, though this is still being investigated. Corn (which was originally domesticated by natives of southwestern Mexico), is thought to have been cultivated for as long as 9,000 years. Then watch this short video (3:20) on the Russian Fox Experiment. Answer the following question:

  1. How does artificial selection lead to changes in populations over time? (50 word minimum) Artificial selection works the same as natural selection. Except artificial selection is decided by human interference whereas natural selection is caused by nature. Artificial selection requires a variation in population, and a trait that must be heritable. This trait is selected by humans, and then passed down generationally over time. Russian Fox experiment creator Dmitry Belyaev hypothesized that the process of domestication was in part the result of changes in gene expression patterns. Recent studies have shown that he was correct.

Part 2. Evolution and Natural Selection

1. Watch the video on Evolution and Natural Selection (19:47), then answer the following questions. 1. What are two observations and two inferences provided by Darwin and Wallace to describe natural selection as a mechanism of evolution? Variation exists among individuals in a population. More offspring are produced than survive to reproduce. These two statements are observations. Individuals that are better adapted to their environment will be more successful at reproducing. Differential survival will lead to accumulation of traits more suited to the environment in the population over time. These two statements are inferences.

  1. Are mutations usually beneficial or usually harmful? Mutations can be harmful, beneficial, or neutral to the organism. They do not “try” to supply what the organism “needs”. Instead mutations are random- whether a particular mutation happens or not is unrelated to how useful it would be. Sometimes mutations will prevent genes from surviving and being passed onto future generations. Some mutations can be harmful in one environment and beneficial in another. An example of this is a mutation that increases the warmth of a mammal's fur.
  2. Which populations have higher frequencies of sickle cell alleles and why? How is this an example of natural selection? Africa and Arabian peninsula because the mosquitoes here are commonly carriers of the malaria parasite. Sickle cell allele is beneficial here, in other places being a carrier puts children at risk for sickle cell anemia. This is an example of natural selection because over many generations a trait has been selected for in a population (Africa / Arabia ) and selected against elsewhere. 2. Watch the following video on Rock Pocket Mouse Evolution (10:31), then answer the following questions.
  3. Where did genetic variation in the rock pocket mouse population originally come from? Random, rare, event.
  4. How long does evolution take? Give an example from the Rock Pocket Mouse video to support your answer. Evolution is never ending. It has no single schedule. It’s always adapting and repeating. It can happen very quickly or take billions of years. One in one hundred thousand mice born may be black. Hundreds of thousands of mice are born in any given year. And then those mice that are black have enough advantage that their babies do better, and they have more offspring, and their offspring have more offspring. And just about a 5% advantage, compounded year in and year out can very quickly turn the whole population black.

Part 4: The Geologic Record

Watch this video on the Geologic Record. Then answer the following questions:

  1. What can we learn about the history of life on Earth through the geologic record? Why is this important for learning about evolution? Biologists think life began in the ocean. This would help them have a better understanding of the evolutionary timeline. Finding trilobite fossils that are 500 million years old. Finding bony fish fossils allowed scientists to place bones on the fossil record for the first time.
  2. When over 80% of known species were killed in the last mass extinction event, what would become of the remaining species that were not killed? They would continue to evolve.
  3. Optional: Read this article about insect decline and the current mass extinction event. What do you think? Watch this video on Stromatolites (~6 minutes), then answer the following question :
  4. What do stromatolites tell us about the evolution of life on Earth? It is amazing! Earth was unrecognizable and uninhabitable for almost all of todays creatures. Stromatolites thrived! Stromatolites are the earliest fossilized form of life found on Earth (3.5 billion years old). They are a continuous record of life thriving on planet earth. Watch these videos on whale evolution, then answer the following questions. Whale Evolution 1(9:50 minutes) Whale Evolution 2 (6 minutes)
  5. Describe at least 4 lines of evidence that exists for the evolution of whales from land-dwelling mammals. (75 word minimum) Whales have an involucrum, a thickened kind of bone in the middle of the ear. This led scientists to believe that whales are a descendant of the Indohyus. A small deer-

Part 5: Evolution of Antibiotic Resistance

Watch this video on the evolution of Antibiotic Resistance. (Optional: Read about the Lederberg Experiment.) Then answer the following questions:

  1. How do bacteria become resistant to antibiotics? When DNA is replicated from a mother cell mistakes can happen. Replication errors create mutations. So a daughter cell could have a mutation that causes that daughter cell to be resistant to antibiotics. Bacteria cells divide very frequently (up to once every ten minutes), meaning this spread of resistance from one cell to another can happen very quickly.
  2. How are bacterial resistance genes spread from bacterium to bacterium, and how are they spread throughout the environment? Through horizontal evolution, of which there are three types. Conjugation: Separate section of DNA that can be passed from one bacterium to another Transduction: virus called a phage will inject DNA from another bacterium into its next bacterial “victim”. Going from one bacterium to another sometimes involuntarily picks up some other bacterium's DNA and passes it on to the next bacterium. Transformation: resistant bacterial cell dies and its genes are located randomly in the environment waiting to be picked up. Bacterium recipient cell can gather these pieces and incorporate them into itself thereby becoming resistant. When antibiotics are used in animals, they can develop resistance in their guts. Which can then spread to the fertilizer used for crops, which then goes to stores and gets into people (eating crops or meat). It can also spread through a human taking antibiotics like this. And can get into water supplies and effect entire ecosysytems.

Part 6: Human Evolution

Watch this video on Human Evolution by PBS, then answer the following question:

  1. What do you think about what the narrator said?

I think it was very interesting and I agree with what they said. In Darwin's era his claims must have seemed absolutely outrageous. However now with genome sequencing we can back his claims of a common ancestor with science. Pretty cool

Part 7: Acceptance of Evolution

As we look at the origin of species on earth using scientific evidence, it is important to acknowledge the diversity of ways in which people integrate science with their other beliefs. Optional Reading: Below I have provided a variety of perspectives for reconciling evolution with faith and/or religious/cultural beliefs. While I cannot provide an example of every perspective, I have selected a number of different examples for you to consider. (Please also feel free to do your own research- I would love some more resources to share if you find them!) ● Khan Academy. Read this article called Darwin, Evolution, and Faith about three potential relationships between belief in the book of Genesis and evolution. ● Pope Francis. It was Pope Francis who said, “God is no magician with a magic wand…,” calling for faith that incorporates evolution. To learn more about his perspective, read this article by NPR here. ● Francis Collins. Francis Collins is the former director of the NIH and founder of the Human Genome Project (he sequenced the first human genome) who says that his work in biological science enhances his faith. Read more here. Or read an interview with him here. ● Read this paper in Nature about Evolution and Islam, by professor and scientist, Mohammed Alassiri. ● What Makes Science Science? Read more about why it’s okay to accept science even with some measure of uncertainty and an ever changing consensus, in this NPR opinion piece here. ● Smithsonian Institute National Museum of Natural History. A primer on Science, Religion, Evolution, and Creationism. Read here. Personal Response: Question 1: Did you grow up in an environment of evolution acceptance? Yes. Both of my parents believe in science thoroughly. Question 2: What would you consider to be the most compelling evidence for evolution by natural selection? Genome sequencing. Showing how close chimpanzee DNA is to human DNA. Question 3: Do you think the evidence alone is enough to accept evolution? Why or why not?