News: Tracing Human Life.

Tracing Human Life

http://www.dallasnews.com/sharedcontent/dws/spe/nie/weeklylessons/stories/20071219-dnnielesson.2f6a48eb.html

10:34 AM CST on Wednesday, December 19, 2007

How well would the human race have survived if its pregnant women kept
losing their balance?making them fall flat onto their bellies or
unable to flee from predators?

Fortunately, women and men are not built the same. In fact, a recent
study on the physical features of the female human's spine shows that
women have more curvature in their lower spine than men. Researchers
have concluded that this human female trait evolved as humans
progressively walked upright.

In primates, who most commonly walk on four limbs, the bulging bellies
of pregnant females fall fairly comfortably between their spines and
the ground. This means that their center of gravity stays generally
the same as when they are not pregnant. In pregnant women, however,
their normal center of gravity shifts. As the baby bulges outward, the
center of gravity shifts outward. A woman's curvy spine automatically
compensates for this, to help shift the center of gravity back into a
more balanced position.

The researchers compared this analysis in Australopithecus fossils.
Australopithecus species are considered early hominids that lived in
parts of eastern and northern Africa around three to four million
years ago. The Australopithecus females showed similar characteristics
in their spines as modern women, compared to the men of their species.
Without this adaptation, hominid women would have experienced
debilitating back pain, making it difficult to outrun predators or
travel long distances, for example.

This adaptation to walking upright has been a key ingredient to human
survival and migration to other continents. Exactly how and when the
first humans arrived in the Americas is still debated. Few dispute
that evidence shows some early migrants walked across a land bridge
from Siberia to Alaska about 11,500 years ago. Mounting evidence,
however, may support other theories, pointing to routes across oceans
and coastlines that may have been used as much as 1,000 years before
the Bering Strait land bridge.

It is unlikely that scientists will ever fill in all of the details as
to how humans lived and migrated in prehistoric times. However,
archeological findings, along with their scientific analysis and
interpretation, continue to shape and support theories about human
evolution.

For this week's lesson, you will explore the world of
paleoanthropology. You will begin with learning about the mechanics of
evolution. Then, you will discover how scientists use physical
evidence to trace the origins, migrations, and lifestyles of
prehistoric humans.

Mechanisms of Evolution

Start your journey with a quick dip in Evolution 101
(http://evolution.berkeley.edu/evosite/evo101/index.shtml), produced
by the University of California Museum of Paleontology. You can
explore the other sections later, but during this lesson focus on the
Mechanisms
(http://evolution.berkeley.edu/evosite/evo101/IIIMechanisms.shtml), or
the process of evolution.

Read the introduction, and then learn about Descent
(http://evolution.berkeley.edu/evosite/evo101/IIIADescent.shtml) and
Mechanisms of Change
(http://evolution.berkeley.edu/evosite/evo101/IIICGeneticvariation.shtml).
With the help of one or more classmates, think of a familiar species
that lives in a particular habitat or region. In writing or
discussion, describe how each mechanism of change?mutation, migration,
genetic drift, and natural selection?could have contributed, in some
way, to the species that exists today.

If you have time, dig deeper into the details of these mechanisms,
including Genetic Variation
(http://evolution.berkeley.edu/evosite/evo101/IIICGeneticvariation.shtml),
Genetic Drift
(http://evolution.berkeley.edu/evosite/evo101/IIIDGeneticdrift.shtml),
Natural Selection
(http://evolution.berkeley.edu/evosite/evo101/IIIENaturalSelection.shtml),
and Coevolution
(http://evolution.berkeley.edu/evosite/evo101/IIIFCoevolution.shtml).
Can you think of another specific case of coevolution? Can you think
of two different animal or plant species in two different regions that
have similar physical features or behaviors? Also, discuss with
classmates how you could you apply these mechanisms in comparing and
contrasting different populations of humans that have evolved in
different regions. What mechanisms most strongly influence today's
human populations? Explain your reasoning.


Becoming Human

Now, you will journey as far back as we can go in the human story to
discover what Becoming Human (http://www.becominghuman.org/) has meant
for our species. Developed by The Institute for Human Origins, this
interactive documentary helps explain how researchers use scientific
evidence to theorize about the physical and cultural evolution of
modern humans. You will need Flash Player and audio speakers.

In each section, you can Play the Documentary in its entirety and then
explore the Related Exhibits, or you can jump to selected exhibits
when the viewscreen prompts that you can Learn More at different
points in the video. (Note: Some videos do not offer jumps to every
Related Exhibit.) When you Close Exhibit, you will return to the point
where you left. As you move through the content, you can also click
underlined key terms for definitions.

Click on the page where it says to Journey through the story of human
evolution, and then Begin the Program. Watch and listen to
Paleoanthropologist Don Johanson's introduction, and then begin
exploring the Evidence section and Play the Documentary. About how old
were the hominid remains found here in Africa? In what ways did Lucy
provide new insight which shifted scientific theories about human
evolution?

Browse through the Related Exhibits, starting with The Scientific
Method. How exactly does the "Circle of Science" work? What are the
three major principles of scientific thinking? In what other
scientific fields have your seen the circle and these principles
applied? Explore the next Related Exhibit, Finding Fossils. How are
fossils and dig sites found and catalogued?

In the third exhibit you will get to Explore a Dig. Here, you will
meet several different types of scientists who work together to
reconstruct what the site looked like and who and what lived there
thousands of years ago. After one scientist explains his or her role,
place your cursor over the Venture Forward icon to move through the
dig site.

Once human fossils are found, then what? In the next Evidence exhibit,
you will learn about Profiling Fossils. How do scientists determine
the species of hominid, the gender, the age upon death, and how
healthy he or she was?

Next, find out how The Dating Game works, why Context Clues are
important, and exactly how scientists go about Interpreting the
Evidence. What are some of the different methods of dating fossils
found at a site? Why is recognizing the context of where a fossil was
discovered critical to interpreting the evidence, and to the Circle of
Science?

Also, learn more about how scientists go about Reconstructing
Environments and what role Environmental Impacts have played in
shaping hominid lifestyles and movements.

Now begin exploring the site's Anatomy section and Play the
Documentary. Explore the various Related Exhibits during the video or
afterward. How exactly are we related to chimpanzees? Why was the
evolution of bidpedalism important to hominid development? What other
kinds of physical and mental skills did our early ancestors possess
that made it possible for them to migrate and multiply so
successfully?

As you will soon discover in the Lineages section, there is still
argument over why the Neanderthals seem to have disappeared. What do
you think happened? How would your viewpoint shape the Human Family
Tree?

Now check out how human Culture evolved. In what ways did
consciousness and creativity influence how they viewed themselves and
others in the world? How did fulfilling our basic needs as a social
group&mdashfor example, food gathering or defending against
predators?help humans develop other skills such as language and art?

--
Bob.

.

Relevant Pages

  • Re: Young Earth Creationist Arguments. Do they realize how they look?
    ... scientists though, ... I don't 'believe' in evolution, I merely accept it as the best ... I suppled a SCIENTIST who believes in the Creation. ... then show that there indeed are true scientists who do ...
    (talk.origins)
  • Re: Young Earth Creationist Arguments. Do they realize how they look?
    ... scientists though, ... The only people who 'believe' that evolution is 'wrong' are those ... I suppled a SCIENTIST who believes in the Creation. ... then show that there indeed are true scientists who do ...
    (talk.origins)
  • Re: Just who is immoral in the evolution debate?
    ... > the evolution THEORY. ... aspects of reality and then tryto find evidence to support or refute ... The mechanism behind evolution is a theory with less support, ... for the most part scientists aren't like that. ...
    (soc.religion.christian)
  • Re: News: Evolution Exposed on the Big Screen
    ... theory of evolution. ... FALSEHOOD #1 ... robust and thoroughly tested theories in any field of science. ... Evolutionary scientists, far from being an "elite group", have far ...
    (talk.origins)
  • Re: A Challenge to Evolutionists
    ... FALSEHOOD #1 ... Scientists are generally as sane as anyone else. ... Evolutionary theory represents mainstream science ... Among the declarations that ran through the thread was that evolution ...
    (talk.origins)
Loading