Anthropology Genetic Reproducing Life

Genetics: Reproducing Life and Producing Variation
Anthropology Genetic Reproducing Life Assignment
CLARK SPENCER LARSEN
E S S E N T I A L S O F PHYSICAL ANTHROPOLOGY SECOND EDITION
CHAPTER
3
Copyright ©2013 W.W. Norton, Inc.
Genetics: Reproducing Life and Producing Variation
Questions addressed in this chapter:
What is the genetic code?
What does the genetic code (DNA) do?
How does understanding genes help us understand variation?
The last chapter ended with a brief introduction to DNA. But, what is DNA? What is it made of? And how can a small molecule like DNA ‘code’ for all of the traits in a living organism? We will address these and other questions in this chapter. Ultimately, what we are doing in this chapter is understanding how the genetic code (DNA) results in variation, because it is this variation that natural selection can act upon and lead to evolutionary changes. We will start by looking at the fundamental unit of all life on Earth: the cell. Inside each cell, the DNA code is structured into packages known as chromosomes. We will see how the DNA molecule can copy itself so that each cell in an organism’s body contains the same DNA information. We will then look at how DNA codes for proteins, which all living organisms are made of. Finally, we will look at a concrete example of how DNA impacts our lives by examining human blood types. Though we have to dive into the microscopic world, do not lose sight of the big picture: DNA is a code for making proteins, and we are made of proteins. If the DNA slightly changes (through mutation, which we met in the last chapter), the protein changes, and thus the organism can change.
Copyright ©2013 W.W. Norton, Inc.
The Cell: Prokaryotes
Prokaryotes
3.5 billion years old
Single-celled bacteria
No nucleus or organelles
All living organisms are made of cells; they are the basic units of life. There are many, many organisms that are made of just one cell, and many (including you) that are made of trillions of cells. All of life can be divided into two big categories, depending on the kind of cell they have. The first kind are organisms called prokaryotes. Prokaryotes are single-celled bacteria without nuclei or any special structures called organelles. They often have structures shown here in this image, like a cell wall, an outer membrane, a cytoplasm within which the DNA resides, and they often have locomotor structures like a flagellum. On this slide is a microscopic image of a prokaryotic cell that we have all heard of: Escherichia coli (E. coli), which lives in the guts of many mammals, including humans. Though prokaryotic cells live within us, and have been instrumental factors in driving human evolution, we will turn now to the cells we are made of: eukaryotic cells.
*
Copyright ©2013 W.W. Norton, Inc.
The Cell: Eukaryotes
Eukaryotes
1.2 billion years ago.
Some single-celled; all multicellular organisms (including humans)
DNA contained in a nucleus
Organelles
All animals, plants, fungi, and many single-celled organisms called protists are made of eukaryotic cells. These cells have a nucleus that contains DNA, and often have membrane-bound parts of the cell called organelles. These include chloroplasts (found in plants) and mitochondria, which help produce the molecular energy that powers cellular processes. Notice in this image that the eukaryotic cell is a bit more complicated than a prokaryotic cell. The microscopic image here is of kidney cells, which clearly have a nucleus, a membrane keeping the components of the cell contained, and a fluid within the cell called a cytoplasm.
*
Copyright ©2013 W.W. Norton, Inc.
The Cell: Somatic Cells and Gametes
Somatic cells
Body cells
Full DNA (humans: 46 chromosomes)
Mitosis
Gametes
Eggs (ova) and sperm
Half DNA (humans; 23 chromosomes)
Meiosis
There are two types of eukaryotic cells in all animals and plants: somatic cells and gametes. Somatic cells, also called body cells, are found all over the body. Shown in the above image are the somatic cells found in the (clockwise from top left) brain, blood, bone, and skin. Somatic cells all contain a complete copy of the organism’s DNA. For example, in humans, somatic cells have all of the DNA packed in 46 chromosomes. Somatic cells also replicate through a process called mitosis, which we will learn about in just a moment. At the bottom right is an image of the other kind of eukaryotic cells: gametes. The large round cell is called an egg, or an ova. The small wiggly structures surrounding the egg are sperm. These are gametes. They contain only half of the organism’s DNA (23 chromosomes in humans) and replicate through a process known as meiosis.
*
Copyright ©2013 W.W. Norton, Inc.
Chromosomes
DNA packaged in chromosomes
Chromosome number varies by species
Number of chromosomes does not correlate with complexity
Since we just mentioned chromosomes, it is worth examining chromosome number in a bit more detail. Humans have 46 chromosomes in our somatic cells. 23 of these came from our mother, and 23 from our father, for a grand total of 46. But, this number, 46, is not special at all. Other apes, like chimpanzees, have 48 chromosomes. Some primates have fewer chromosomes, like the colobus monkey which has 44. Some organisms we would consider to be less complex than us have fewer chromosomes, like the house fly with 12 or the salamander with 24. But, plenty of organisms have more than we have, like the potato with 48, the camel with 70, or algae, which has 148 chromosomes. Classifying organisms by the number of chromosomes they have would be like organizing books in a library based on the number of pages they have, or by the color of its jacket cover. It wouldn’t make sense. What matters are not the number of chromosomes an organism has, but the similarity in DNA that is packaged in the chromosomes. For instance, humans and chimpanzees share about 98% of their DNA. This is remarkable, and, in some ways, indicates how important 2% of a difference can be.
Anthropology Genetic Reproducing Life Assignment
Copyright ©2013 W.W. Norton, Inc.
DNA: The Blueprint of Life
• DNA
Genes
Chromosomes
Genome
• Nuclear DNA:
homoplasmic
• Mitochondrial DNA:
heteroplasmic
Most likely, you have all heard of DNA, and have probably heard that it is the “blueprint,” or “recipe,” or “code” for life? But, how does this work? It helps first to understand the structure of DNA, and to understand how it is packaged in your cells. It is estimated that there is six feet worth of DNA in every cell in your body. Six feet!? If cells are microscopic, how can this be? As shown in this image, the DNA molecule is wound up into compact structures that we have already encountered: chromosomes. Sections of that DNA specifically code for a specific protein in the body: These are called genes. The genome is all of the genes put together in all of the chromosomes. The DNA that is in the nucleus of our cells is called homoplasmic, meaning it is more or less the exact same in every cell in our body. But, the nucleus is not the only place in a cell that contains DNA. An organelle called the mitochondria also contains DNA. Mitochondrial DNA (mtDNA) is much, much smaller; it only contains 37 genes. And these genes are only inherited from your mother, meaning they can be used to trace one’s maternal lineage (called a matriline). Unlike nuclear DNA, mitochondrial DNA can differ from cell to cell, making it heteroplasmic. Anthropology Genetic Reproducing Life Assignment
*
Copyright ©2013 W.W. Norton, Inc.
DNA: The Blueprint of Life
DNA structure
Sugar
Phosphate
Nucleotide base
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
A with T
C with G
CAAAT
GTTTA
Anthropology Genetic Reproducing Life Assignment

Struggling to find relevant content or pressed for time? – Don’t worry, we have a team of professionals to help you on
Anthropology Genetic Reproducing Life
Get a 15% Discount on this Paper
Order Now
Calculate the price
Make an order in advance and get the best price
Pages (550 words)
$0.00
*Price with a welcome 15% discount applied.
Pro tip: If you want to save more money and pay the lowest price, you need to set a more extended deadline.
We know how difficult it is to be a student these days. That's why our prices are one of the most affordable on the market, and there are no hidden fees.

Instead, we offer bonuses, discounts, and free services to make your experience outstanding.
Sign up, place your order, and leave the rest to our professional paper writers in less than 2 minutes.
step 1
Upload assignment instructions
Fill out the order form and provide paper details. You can even attach screenshots or add additional instructions later. If something is not clear or missing, the writer will contact you for clarification.
s
Get personalized services with MyCoursebay
One writer for all your papers
You can select one writer for all your papers. This option enhances the consistency in the quality of your assignments. Select your preferred writer from the list of writers who have handledf your previous assignments
Same paper from different writers
Are you ordering the same assignment for a friend? You can get the same paper from different writers. The goal is to produce 100% unique and original papers
Copy of sources used
Our homework writers will provide you with copies of sources used on your request. Just add the option when plaing your order
What our partners say about us
We appreciate every review and are always looking for ways to grow. See what other students think about our do my paper service.
Nursing
As usual, the writers do amazing work.
Customer 452707, October 1st, 2022
Career Development
Beautiful job
Customer 452901, April 16th, 2024
Medicine
This has everything that was in the rubric. Thank you!
Customer 452707, May 29th, 2022
Social Work and Human Services
Excellent! Done earlier than needed and with more sources than needed! Great work!
Customer 452485, August 22nd, 2021
Nursing
Thank you!
Customer 452707, October 16th, 2022
Other
GREAT
Customer 452813, June 20th, 2022
Nursing
They so amazing work!!
Customer 452707, January 29th, 2023
Human Resources Management (HRM)
Excellent
Customer 452813, December 30th, 2023
Human Resources Management (HRM)
Thanks
Customer 452701, September 15th, 2023
Nursing
Great paper!
Customer 452707, July 1st, 2022
Political science
THANK YOU
Customer 453001, April 25th, 2024
Nursing
Amazing as always!!! :)
Customer 452453, March 16th, 2023
OUR GIFT TO YOU
15% OFF your first order
Use a coupon FIRST15 and enjoy expert help with any task at the most affordable price.
Claim my 15% OFF Order in Chat

Good News ! We now help with PROCTORED EXAM. Chat with a support agent for more information

NEW

Thank you for choosing MyCoursebay. Your presence is a motivation to us. All papers are written from scratch. Plagiarism is not tolerated. Order now for a 15% discount

Order Now