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Essay Available:
Pages:
4 pages/≈1100 words
Sources:
Check Instructions
Style:
APA
Subject:
Biological & Biomedical Sciences
Type:
Essay
Language:
English (U.S.)
Document:
MS Word
Date:
Total cost:
$ 17.28
Topic:

Development of Lactose Persistence. Biological & Biomedical Sciences

Essay Instructions:

Objective
The purpose of this essay assignment is to give you an opportunity to develop your own ideas about human evolutionary biology. You should use the concepts that you have learned in lectures, discussion sections, and your readings to creatively address the questions posed below. If you wish, you may discuss the assignment with other students, but all writing must be solely your own work as per the UC Davis Code of Student Conduct. Links to external websites.
Reading
Check, Erika. 2006. How Africa learned to love the cow. Nature. 444: 994–996. Preview document
Assignment
Your assignment is to read Erika Check’s article about milk tolerance in adult humans and answer the following questions in the form of an essay. Each of these questions requires you to describe, or make predictions based upon, evolutionary processes. You should be explicit about the relevant evolutionary principles in your answers.
Why can individuals from only some human populations tolerate milk as adults?
In your own words, describe in detail the genetic changes that allow for milk tolerance in adult humans.
What do these genetic changes tell us about the evolutionary history of milk tolerance in human populations?
What would you expect to happen to the percentage of the population who could tolerate milk if the individuals in the population stopped drinking milk (or milk products, e.g., cheese) due to the increased availability of other foods? Why?
Neandertals are a fossil human species that lived in Europe and western Asia between about 200,000 and 40,000 years ago, subsisting exclusively on hunted and gathered foods. Based on your knowledge of milk tolerance in humans, would you expect that Neandertals were able to tolerate milk as adults? Explain why or why not.
IMPORTANT: Do not use direct quotes from the Check article, instead summarize points and arguments in your own words.
Grading
This essay assignment is worth 11% of your grade. Essays are expected to be between 800-1,000 words (approximately four pages). Your essay must be submitted directly into Canvas as text, and it will be graded for content as well as for clarity. Clarity refers to organization, focus, development of ideas, style, and mechanics (grammar, spelling, etc.).
Please put your name, your TA’s name, and your section time at the start of your essay, along with the title of your paper. Be sure to cite any sources (including the reading, textbook, and lectures) you use in writing the essay. If you are unsure of proper citation format, please see your TA.
Writing Assignment 1
Writing Assignment 1
Standard Grade Score
This criterion is linked to the learning results Content
Should include
- Why can only some individuals tolerate milk (1 pt)
- Description of genetic changes (1 pt)
- What do genetic changes tell us about evolution of milk tolerance (1 pt)
- What would happen if a population stopped drinking milk (1.5 pts)
- Response to questions about neanderthals and milk (1.5 pts)
6.0 得分
Full Marks
5.0 得分
Partial credit
4.0 得分
Partial credit
3.0 得分
Partial credit
2.0 得分
Partial credit
1.0 得分
Partial credit
0.0 得分
No Marks
6.0 分
此标准已链接至学习结果 Application of key ideas
Should include:
- Integration of lecture/textbook ideas (2 pts)
- Independent, creative thought (2 pts)
4.0 得分
Full Marks
3.0 得分
Partial credit
2.0 得分
Partial credit
1.0 得分
Partial credit
0.0 得分
No Marks
4.0 分
此标准已链接至学习结果 Clarity and style
Should include:
- Introduction and conclusion (1 pt)
- Focus and organization (2 pts)
- Mechanics and style (2 pts)
5.0 得分
Full Marks
4.0 得分
Partial credit
3.0 得分
Partial credit
2.0 得分
Partial credit
1.0 得分
Partial credit
0.0 得分
No Marks
5.0 分
总得分： 15.0 ，满分 15.0

Essay Sample Content Preview:

Writing Assignment One
Your Name
Subject and Section
Professor’s name
January 25, 2020
Milk is perhaps one of the most indispensable commodities for every person. Just like any other mammal on this planet, the offspring of humans need milk (both breastmilk and synthetic ones) to survive and develop during its early ages. Even advanced societies have developed milk substitutes that are developed for the elderly to attain their daily nutritional needs. However, as studies would show, humans, are not designed to be entirely dependent on milk. Almost all adults (except for Europeans) experience difficulty in digesting lactose – milk’s primary compound – due to the lack of lactase (the enzyme used to digest it) within their bodies. Nevertheless, anthropological studies have shown that environmental, societal, and societal structures can affect an individual’s ‘lactose tolerance’.
In an article written by Check (2006), she discussed how individuals from pastoral and semi-pastoral communities seem to have developed the capacity to utilize milk due to both internal and external factors. In this article, the effects of both the environment and evolution would be discussed in relation to African milk tolerance. Just like how Check (2006) discussed, the author of this article also believes that by analyzing patterns of lactase persistence in different societies, it becomes easier to understand how human evolution and cultural factors relate to one another.
The Development of Lactose Persistence
           As stated earlier, it is a scientifically proven fact that most human adults are not designed to rely on milk as sustenance for their needs. In fact, in most cases, drinking milk can be more disadvantageous than beneficial since adults who drink milk cannot digest and absorb the nutrients that it contains, while it also creates an unpleasant feeling within their stomachs. However, several studies have shown that individuals from societies that rely on cows have developed this capacity through evolution and adaptation. In the succeeding sections, the author would discuss some of the processes such as (1) mutation and (2) natural selection, and (3) convergent evolution.
Mutation
           Despite the number of ways in how different species could adapt to environmental changes, one of the ways on how lactose persistence could develop in humans is through the process of ‘mutation’. A mutation is defined as the random and minute changes that happen in one gene structure thereby leading to different phenotypic results for an individual. Going back to this case, it shows that mutation happened at one point in the individual’s LCT gene, which made them capable of digesting lactose even as an adult (Leonardi, Gerbault, Thomas, & Burger, 2012).
While mutations are usually isolated and relegated to become a recessive trait, if such is coupled with a certain ‘reproductive advantage’, then it becomes passed to subsequent generations and spreads throughout the community as a result. To understand how this relates to lactase persistence, the next section would discuss the concept of natura...
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