Weston Middle School
Life Science Course Materials
The great physicist and Nobel laureate, I. I. Rabi, was once asked what accounted for his professional and scientific success.
He said that when most kids came home from school, their mothers asked, "What did you learn today?" His never did. Instead, she would inquire, "Izzy, did you ask a good question today?"
Sequence based on that of Prentice-Hall Biology, by Miller and Levine
I. Prologue- Classroom Policies and Procedures/ Lab Safety/The Nature of Inquiry-Based Science.
In the first week, the students should be introduced to classroom policies and procedures, keeping a course notebook, lab safety, and all the rest. But more importantly, perhaps, they should be introduced to a sense of wonder at the natural world,to the importance of careful observation and measurement, and that science is a way of knowing, not a bunch of vocabulary words. DON'T SPEND THE FIRST DAY TALKING AT THEM! GO OUTSIDE! Let them explore the woods, find as many different kinds of organisms as they can- lichens, worms, mosses, trees, and what not. Close their eyes, unplug their Ipods, and listen to as many different sounds as they can.
After the policies and procedures, etc. have been gone through, there are a variety of labs they can do. The One Small Square lab, based on the books of that name by Donald Silver, gets students outside again, this time for a more thorough examination of a square meter. The measurement lab reviews the use of a variety of measuring devices ( and also provides a source of apples which can be set aside to rot slowly in the corner for a decomposition lab- shades of Spallanzani vs Redi).
The heart rate lab, while thematically part of the human body unit, demonstrates the use of dependent and independent variables, as well as letting the kids enjoy the outdoors again. These labs can be repeated later; studies show that repeating a lab, after analyzing a first run, greatly increases student understanding. Another lab using independent and dependent variables can also be used.
Keep in mind that, while students will be exposed to a great deal of learning, which will prepare them to be better citizens, for high school and beyond, our chief objectives are:
- That students will enjoy science, so they will want to learn on their own;
- That students will be introduced to the wonders of the world around them, whether a bit of moss or the color of their hair.
CHOOSING WHAT NOT TO TEACH
Before I discuss the regular 'content' units, it should be mentioned that one of the great challenges that all teachers face is the issue of 'broad' vs 'deep' coverage. All research on how students learn shows that it is far more effective to explore a few topics in great depth than a large number of topics superficially. Yet between our own interest in certain topics, the Massachusetts Frameworks, and the exquisite beauty in so much of biology, this is a very hard choice.
NONE of what constituted biology in the last century- botany and zoology is part of the Massachusetts Frameworks. Yet I think we have a duty to help students understand the living world around them- if students become too isolated from nature, and see it as something separate from themselves, they will no longer value it and preserve it.
II. Environmental Science: Setting the Stage for the Story of Life.
Environmental science is one of the major unifying themes of biology, for it is the living and non-living components that determine what species will thrive and which will die off. It is changes in the environment, whether millions of years ago or in the present day, which is a major driving force of evolution .
For example, for the first few billion years of earth's history, only bacterial life could exist, due to the low oxygen levels; as oxygen levels increased, some scientists believe, true cellular respiration came into being; when they arose still further, bodies ( the Cambrian Explosion) could then occur. Today, global warming is causing similar changes in which species are most successful.
The Environmental Science Unit provides a basis for understanding cellular physiology and plant and animal evolution, as well as introducing concepts of photosynthesis, respiration, and symbiotic relationships, which are then explored in greater depth in several later units, without requiring any prior biological knowledge. As eukaryotic cells( studied in the next major unit) are thought by many to have come about through symbiotic relationships between various types of bacteria, it is helpful to study symbiosis first.
While many teachers begin life science with the study of classification, I feel it is useful to delay this until after the study of evolution( see below), which should be the great organizing principle for the year; otherwise biology can become 'just one damned fact after another'.
As environmental science is, along with cell biology, a major chunk of the Massachusetts middle school life science Framework, it is also advantageous to study it at the beginning of the year, rather than the end, when various scheduling quirks ( MCAS, assemblies, etc.) might force teaching time to be curtailed.
In addition, by placing it at the beginning of the year, students are able to do out-of-doors projects such as the Leaf Project and the Pond Study while the weather is still pleasant; also sending the message immediately that biology is about the actual living world, not just something in a book. Other projects include paper recycling and organic composting.
Environmental
Science should wind up before the Thanksgiving break. There is probably
not time in the year to devote separate study to environmental issues;
accordingly study of the policy/political ramifications of environmental
science should be incorporated throughout the unit wherever appropriate.
III. Cell Biology
As the weather grows colder after Thanksgiving, and the stage has been
set through the study of the environment, our story moves indoors, to
the study of the common structures and physiology of all eukaryotic cells-
cell theory, organelles, DNA, and heredity.
The eukaryotic cell, which with its complex structures and exquisite biochemical machinery may have taken billions of years to evolve. Many organelles, such as mitochondria, chloroplasts, and ribosomes, retain their own distinct DNA and ways of extracting energy, hinting at their possible evolutionary origins as distinct bacteria.
Understanding how a single cell grows, communicates, uses energy, moves, and reproduces gives a better understanding of how multicellular organisms create specialized organs and tissues to carry out these functions.
IV. Heredity
The Heredity unit (part of the Cells and Heredity book ) studies are traits are inherited; alleles ( variants of traits); how genes are re-shuffled during meiosis; and how DNA provides a "blueprint" for the building of proteins. An amazing cast of characters as well- Mendel, the monk whose work was ignored; Watson and Crick; Rosalind Franklin, and all the rest.
V.
Evolution
Evolution ( the last part of the Cells and Heredity book) helps
students understand how the life processes, and the diversity of life,
arose in their environmental context, and how genetics shows how all life
is inter-related and shares a common orgin; how body plans are inter-related,
etc. A major MCAS topic as well.
VI. Classification
The study of the diversity of life, and how it is classified, makes much
more intuitive sense here, as the study of evolution helps students understand
how the variety of life forms arise. Because at this point students have
learned about common life processes, mutations, and how evolution and
environmental pressures cause changes in plants and animals, the diversity
of life-forms can be seen as a whole, rather than a set of arbitrary divisions.
VII. The Plant Unit somewhat arbitrarily deals with stuff
you can see- fungi, gymnosperms, angiosperms, and the like. Photosynthesis,
respiration, autotrophs/heterotrophs, symbiotic relationships, etc., which
were introduced in the fall, are here explored in greater depth, and the
structure of plant vs animal cells is revisted and reinforced. The MCAS
does not test traditional botany; how much not to explore is
always a difficult choice.
VIII.
Animals make sense in this place in the year, as illustrations
of evolution in action. An Animal Report is often assigned as part of
this unit.
Plants and Animals often must be rushed through somewhat; they are not
major Frameworks topics; there are unlikely to be many MCAS questions
on it. Yet as teachers it is our duty to help students understand the
world which they see around them; how can we not introduce them to the
plants and animals which surround them?
IX. Organ Systems/Human Body.
By now, one is coming into May and June, when student interest typically is flagging. However, adolescents are typically most interested in this area ( having an unceasing interest in themselves and the changes occuring to them) which helps compete with the nice weather. If you don't get to a few systems it is not critical in terms of MCAS. The earlier study of body plans and evolution helps to make sense of the various organ systems, whose tissues all have specialized proteins (studied earlier in Cell Biology) which enables them to be more efficient.
And no one says you cannot do exercise physiology experiments outdoors,
or take the class out to the pond now and then, just because it is a nice
day...
How can we help students experience what we teach as an interconnected
whole, rather than as a disparate series of topics?
If there is one big idea, one organizing principle in modern biology, it is evolution- that all life on earth descended from a common ancestor, and shares one common set of biological machinery, and much of the same genetic information.
Links
Alternate theories:
Symbiotic relationships as a driving force for evolution
Last Child in the Woods:Saving Our Children from Nature-Deficit Disorder
Getting Out: