The Axial Skeleton
"I've come for the bones, the precious bones, the jade bones.  Can I have them in order to populate the earth?" - Quetzalcoatl

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Welcome to my Physical Anthropology 101 student page. Physical anthropology deals with the examination of the human species beginning with the exploration of our earliest hominid ancestors, which date to some six/seven/eight million years ago. This was a time when we evidently split into a fully bipedal species (walking on two legs). Our work proceeds alongside models provided by the great ape species (gibbons, bonobos, gorillas, chimpanzees, and orangutans). We are interested in how the human body has adapted and changed in the wake of natural occurring forces, such as genetic drift, migration, mutation, and natural selection. This is what physical anthropologists call an evolutionary approach to understanding the human body. The approach aids our understanding of the human biological context, past, present, and future.
As physical anthropologists, we follow a behavioral ecological model that integrates plants, animals, and the environment alongside the evolution of the human body. Being aware of these inter-related biological processes helps us better engage food and the environment, in order to promote positive health and well-being of the long-term type. We are interested in the examination of race and ethnicity from a human skeletal and genetic base, to best promote racial relationships among populations, in all places of the world. Because our efforts stem from an understanding of anthropological theory and method, the scope of our work is truly holistic, bridging cultural, archaeological, linguistic, and historical evidences into vast paradigms. Our methodologies encompass excavation, analysis, and re-construction, to simulate the past, present, and future. Most of our work spans across the field, the laboratory, and in the classroom, delivering knowledge's, posing questions, and building dynamic models to live by.
One of the major resolves of this site is to bring back that awareness of the human body that has been lost. Knowledge of the human body has been overwhelmingly blinded by demanding work and school schedules, media outlets, and advances in technology that do little to emphasize the body’s health, and wellness, and its developments. Little do we know that our bodies are constantly evolving, reacting to the material and natural environment, and asking for our care, do we care? The biggest questions of the Anthropocene (see Steffen et al. 2011), ask that we re-evaluate how we heal, grow, and positively interact, with other humans. It is important that we understand not only the basic body plan (cells, tissues, and organs) but also the dominant phenotypes that power our ethnic, gendered, and sexual orientations. How we as a human species can halt the destruction of our bodies and plant? That process begins with physical anthropology, the study of the human body and all its relationships.
In the following sections, you will find a series of blogged visuals (pictures), texts, and lecture notes relevant to physical anthropology. The material comes directly from my classroom and laboratory experiences in teaching cultural and physical anthropology at the college level. The material I present in a sequential order comprised of 10 basic lesson plans for your learning. The site, like all of my work, is constantly "evolving," so please check back randomly for new postings.
Attention Cerritos College students, I am currently mentoring students by way of independent study. Students enrolled in the Honors Program, and in my physical anthropology theory course, may request an advanced-learning track, with the approval of a project by the Honors coordinator.

Steffen, Will, Jacques Grunewald, and Paul Crutzen
2011    The Anthropocene: conceptual and historical perspective Phil. Trans. R. Soc. A 369: 843

Measurement of the nasal breadth and height

Lesson 1 The Basic Body Plan

The Basic Body Plan
THE BASIC BODY PLAN consists of cells, tissues, and organs. The cell is the basis of all life and they are constantly reproducing in our bodies to help us heal, grow, and biologically reproduce offspring. Tissues, like muscles, arteries, and skin, are all created from cells. More complex tissues, organized ones, form to make up the different organs in our bodies. All organs, work with other organs to function as organ systems, such as the reproductive system, the cardiovascular system, and the digestive system, just to name a few...

THE BASIC BODY PLAN: A CLOSER LOOK

Cells  

Cells are the basis of all life.  They are in charge of arranging molecules into living matter.  ALL plants and animals have cells.  Humans are believed to be carrying up to 100 trillion cells!  Though we don't think about it, cells are constantly reproducing in our bodies to ward off uncalled for bacterias and virus, to replace dry skin, to grow hair, to produce blood, etc.  Just about any task you can think of that occurs in the body, begins with a cell.  Outside of these processes, cells are unique for they all contain the deoxyribonucleic acid (DNA) formula that contains our genetic information (see Lesson 2).

Two types of cells in the human body

1.  Somatic Cells, the types of cells in our body that are used daily to help us heal, grow, and properly function.

2.  Gametes, (sex cells), the types of cells that are found only in the reproductive system of the human body.  Sperm cells (male), and egg cells (female).

Two types of cells in the human body

The Cell Structure

The Cell Structure
1.  Plasma Membrane,  A double-layered membrane, composed of phospholipids and protein molecules, that gives form to the cell and controls passage of material into and out of the cell.

2.  Nucleus, Contains the genetic material (DNA), separated from the rest of the cell by a nuclear membrane.

3.  Nucleolus, Seen as a dark mass in the nucleus, made up of proteins and ribosomal RNA, and the site of ribosome production.

4.  Cytoplasm,  Fluid, jelly-like substance, between the cell membrane and the nucleus, in which the organalles are suspended.

5.  Mitochondria, Oblong organelle where adenosine triphosphate (ATP) production occurs; ATP is the carrier of chemical energy in the cell.

6.  Ribosomes, Small structures made of proteins and RNA that "read" the RNA strand during protein synthesis; occur free and on endoplasmic reticulum.

7.  Endoplasmic reticulum (e.r.), Membranous network of channels in cytoplasm, continous with nuclear membrane, that forms a pathway for transporting substances within the cell and stores synthesized molecules (intracellular circulatory system).

8.  Centriole, Pairs of organelles composed of microtubules; organizes the cytoskeleton for cell division.

9.  Lysosome, Sac-like attachment to cell membrane that digests unneeded molecules; formed from vesicles of Golgi body.

10.  Golgi body and vesicle, Delivery system of cell, which collects, modifies, packages, and distributes vesicles, molecules that are synthesized at one location and used at another.


CHROMOSOMES (see also Lesson 3)

Most of the genetic information/material, deoxyribonucleic acid (DNA), that offspring inherit from their parents is located in the nucleus of cells.  DNA is furthermore always packaged into chromosomes.

Chromosomes are visible only during cell division when they condense and contract.  When cells are not dividing chromosomes remain uncoiled and defuse into a single-form called chromatin.  When chromosomes are in their double state they comprise of an "arm," "centromere," and a "sister cromatid."

DNA is always packaged into chromosomes

CHROMOSOMES IN HUMANS

In humans the number 46 refers to the amount of chromosomes that are found in somatic cells... 23 of these came from the male sperm, while the other 23 came from the female egg.

Diploid (46 chromosomes)

Haploid (23 chromosomes) contained within the gamete (egg or sperm)

When a haploid egg and sperm combine they form a fertilized egg called a zygote containing 46 chromosomes.  The zygote quickly transforms/divides into a somatic cell (mitosis) and through a process called differentiation develops into three embryonic layers (endoderm, mesoderm, and ectoderm) that further devlelop into primitive organs, the skeletal system, the nervous system, and eyes.  Human life begins!

Lesson 2 DNA, Cells, & How Cells Are Made

Deoxyribonucleic acid
Deoxyribonucleic acid, or DNA is a large molecule in the nucleus of all eukaryotic cells.  Along with various proteins, DNA is "packaged" into chromosomes that reside in the nucleus of every cell in the human body. DNA is important for two vital processes:

1.   Replication (making a copies of itself)


2.   Protien sysnthesis (the manufacture of proteins)


These two processes (replication and protein synthesis) are important for growth and development, and for the passage of genetic information from parent to offspring, or on a macro-scale, from generation to generation.


Knowledge of DNA structure and function, and how DNA sequences are inherited allows us to: 1) be aware of the risks of transmitting genetic diseases to our children, 2) identify biological relationships between individuals and species, 3) track evolutionary shifts within our own human species, and 4) identify perpetrators of various crimes.



Nucleic Acids

Within all eukaryotic cells there are two types of nucleic acids, DNA, and RNA.  DNA contains our actual genetic information, while RNA, consisting of similar substances is a vital  "helper" of DNA.

The building blocks of DNA are known as nucleotides, comprised of 1) a sugar molecule [deoxyribose], 2) a phosphate molecule, and 3) a base.

You should know that there are four base types particular to DNA and RNA, made of simple atoms of hydrogen, carbon, oxygen, and nitrogen.  

The four bases of DNA are:

1.  A = adenine
2.  T = thymine
3.  C = cytosine
4.  G = guanine
5.  U = uracil (only found in RNA)


The building blocks of DNA

The Structure of DNA

The number of nucleotides strung together (2) are known as a polynucleotide chain.  All DNA consists of two polynucleotide chains.  Lastly, the DNA molecule is called a double helix, because it appears as a helical-twisted structure that gives the appearance of a twisted ladder.

The "backbone" or sides of the ladder are comprised of phosphates, while the "steps" of the ladder are comprised of base pairs (adenine, guanine, cytosine, and guanine).  The phosphates of the ladder are held together by strong chemical bonds, while the base pairs are held together by weak hydrogen bonds which can be easily broken by enzymes during cell replication.

It is important to know that the pair of bases in DNA adhere to specific "rules."  Adenine and thymine consistently bond together, as do cytosine with guanine.



Summary of Genetic Material


Protein Synthesis:  How Genes are Expressed



HOW ARE CELLS MADE?


All humans start their lives as a fertilized egg called a zygote from which we derive all cells in our body.

Lesson 3 Gregor Mendel & Inheritance


Lesson 4 The Major Forces of Evolution


Lesson 5 The Human Skeleton




Lesson 6 Biological Classifications & Living Primates