Biology I - Article Abstract 1 – 25
Points
INSTRUCTIONS: Read the article
and produce an abstract of it, outlining the articles important points (see bottom).
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Assembling
the Tree of Life.
By Emily Sohn, published in Science News for Kids,
May 31, 2006.
It's easy to
see how you're related to your parents, grandparents, brothers, sisters, and
cousins. It's not so easy to see how you're related to apple trees, worms, or
elephants. From algae to zebras, all living things on Earth have a common
ancestor. The Tree of Life Project aims to show how these species are related
to one another by putting them into a family tree. Biologists and other
scientists all over the world are working to identify and sort Earth's
organisms—from plants to microbes to animals, living or extinct—to see how they
fit together.
By organizing
knowledge of living things into a single evolutionary tree, researchers hope to
create a tool that will help them unravel the underlying rules that drive life
on Earth, in all its diversity. "There are many, many things we can
understand better if we realize that the organism we're looking at doesn't
exist in a vacuum," says Scott Lanyon. "It's actually related to
other things." Lanyon is director of the Bell Museum of Natural History in
Millions
of species. So
far, scientists have identified about 1.7 million species around the world. At
least 4 million more species remain to be discovered. And these numbers don't
include the millions of species, such as dinosaurs, that have already gone
extinct. Amazingly, this diversity apparently arose from a single primitive
organism that lived roughly 3.5 billion years ago. Over time, cells formed,
changed, and merged. Groups of cells developed into distinct organisms,
splitting into different species that could not reproduce with each other.
For most of
history, no one was around to record what was happening. So, there are lots of
gaps in the record and many questions about how, when, and where species split.
Extinct creatures aside, scientists have plenty to learn about links among the
different species of plants, microbes, and animals that are living today. Biologists
who specialize in studying ants, frogs, plants, monkeys, or some other group of
living things, for example, don't always know how their own discoveries might
relate to findings about other species.
Male
red-winged blackbirds, for example, are more brightly colored than females.
"To understand why, it's helpful to know what the closest relatives to
redwings do," Lanyon says. "But to answer these questions, we have to
delve into the past. We have to talk about history." Katja
Schulz, an entomologist at the
DNA
tests. Getting a
detailed look at the past has become possible because of recent advances in our
understanding of the genetic material DNA, which is found in all cells.
Changes, or mutations, in DNA drive evolution. Members of the same species
start with lots of DNA in common. But as species split, their DNA becomes less
similar. Using new technologies, scientists can compare stretches of DNA to
find out the point at which two organisms split from their common ancestor.
Supercomputers
do the math required for making such comparisons. But even computers have
limits. "If you have DNA for four species, it doesn't take a computer long
[to make a comparison]," Lanyon says. "But when you have thousands of
species, you quickly get to the point where computers can't handle it."
"This is a huge nightmare for computer scientists," he adds.
"We're producing data much faster than we can analyze it in a
sophisticated fashion."
So, there's a
lot of research aimed at improving computers and the methods that they use to
make comparisons. Even though it's far from complete, the evolutionary tree of
life can be a great resource for scientists, Lanyon says. Several decades ago,
for example, scientists found a compound in the bark of the Pacific yew tree
that helps fight cancer. Unfortunately, this yew species contains only tiny
amounts of the stuff. By checking the tree's closest relatives, researchers
were able to find another species that produces a larger supply of the
compound.
Web
project. As some
scientists struggle to assemble a complete evolutionary tree, researchers at
the
At this
point, the site contains more than 4,000 pages. And it's getting bigger all the
time. "When you see that humans and jellyfish share a common
ancestor," Schulz says, "it makes you aware that all life on Earth is
one big community." Schulz is the project's managing editor. Only experts
can add information to the evolutionary tree, but anyone can contribute to the
Web project. With your teachers, you can build "treehouses"—special
pages on the Tree of Life Project Web site where you can post your own
scientific studies, poems, pictures, stories, or art projects. The only
requirement is that your treehouse must be about organisms in some way, Schulz
says. Each contribution also has to be original.
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1. List the title of the article, the
author, where it was published, and the date it was published.
2. Give me one sentence telling me what
the article is about.
3. What is the name of the “Project” that
the article is talking about?
4. What are the goals of this project?
5. What part or aspect of the creatures
they are studying will help them determine relationships between
species?
6. How is the University of Arizona
helping to make the information these scientists are working to collect
accessible to the public?