Download Biology of Seed Plants Laboratory 1 - spring 2014 John

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Biology of Seed Plants
Laboratory 1 - spring 2014
John H. Crow, Ph.D.
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© 2014 John H. Crow, Ph.D., all rights reserved
Seed Plants - Laboratory 1 - spring 2014!
Page 2
The Plant Body
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General Information
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The objective of this laboratory is to begin to discover and explore the form of the plant. This
will involve studying the outer morphology and gross anatomy of a variety of common plants –
any plant will do. Understand that there is no set number of tasks or specific exercises to do in
this lab session but some lesson guidance is put forward as a minimum. Also, we will continue
with the same general type of exercise next week but overlapping with other work. The more
you do using unprepared slides and materials, the more you will truly learn.
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Please refer to the class website at http://www.drcrow.org for information about lab and lecture
requirements and grading. Understand that you have to participate in laboratory and perform
well each and every week. If you cannot commit to this, drop the course now.
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Before you begin, make sure that you have white, unlined paper on which you can draw, make
graphs, etc. You must get a lab kit at New Jersey Books or the Rutgers Book Store that will help
you do dissections, make slides, etc. We recommend getting a magnifying glass (hand lens); it
will be very useful to you and, if you call yourself a biologist, you should have a good one (I
recommend the Bausch & Lomb 10X Hastings Triplet hand lens at about $33.00 and it will last a
lifetime).
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As a first step, we will begin by selecting lab team members to work with. This proves to be
more efficient when doing repetitive tasks and is a means to teach and test each other. Two or
three of you should make up a group. Report the group member names to your lab instructor and
give the group a name or letter identifier ("A” Students Group, for example). This group will
work together the entire semester and sit next to each other in lab.
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In this laboratory we are going to examine the features of a number of plants that are provided.
Some of the plants come from the campus and others come from the Rutgers greenhouse or
elsewhere. You will also find a number of the illustrations provided in this set of laboratory
materials that I hope will be useful.
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We will begin with some basics concerning different kinds of plants. This work will begin
simply but it is fundamental and easy, on the one hand, but truly profound, on the other. Mastery
as you go along is important to your overall success in the course and beyond. Don’t assume
that you know the material going in! I can prove to you pretty quickly that you don’t really
know a lot of what you think you do. Carefully think about everything.
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© 2014 John H. Crow, Ph.D., all rights reserved
Seed Plants - Laboratory 1 - spring 2014!
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General Instructions
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Where appropriate, examine the plant materials and try to sketch what you see. This does not
require artistic talent but some patience and good observational skills. Use magnification too.
How do the magnified structures relate to the body of the plant? Professor Crow will provide
some discussion of how to go about this in lecture. Always make sure that you know the relative
size of what you are looking at and where the magnified view is located. If you do this, you will
better understand the plant and what you will be seeing.
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In this first laboratory we do not care too much about precise names for the things you are
seeing. We care about making good observations and that you actually see the parts of the plant.
We will put names on the things you see soon enough. The words will connect your brain what
you see so make careful observations. In fact, some of the things you observe you may have
already learned about in lecture and here you can see exactly what Professor Crow was talking
about. If so, label accordingly. If not, don't worry! Make sure you see everything. We can
always add labels. Your sketches will help guide you through the process of making better and
better observations. Some drawings can be diagrammatic, but try to make sure that what you
draw will be helpful when you want to recall what the plants feature really looks like.
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Plants tend to have clear sets of patterns. So, if you learn these patterns, you will much more
easily recognize what you are looking at and appreciate the variation and beauty of nature.
Professor Crow will help you with these and the laboratory will give you a chance to observe the
patterns in living, preserved, diagrammatic, and photo representations of plant materials.
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Not only does the external morphology of the plant have clear patterns, but the anatomy of the
plant is also important and is supremely rich in diagnostic patterns you can easily learn. Looking
inside a plant will require some patience and a little skill but you will master it quickly if you
care to. This week we are emphasizing herbaceous plants; woody plants will come next week.
Rather than merely chopping up the plants, try making thin slices or peels of various plant parts.
Do this on stem, leaf, and root parts. If you keep the sections wet and properly prepared, you
will have the best luck making observations under a microscope. Stains will help. We also have
selected prepared slides to fall back on but I caution you to do as much as possible with the fresh
materials and try to avoid the prepared slides until the very end.
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Go from big to small. Look at the whole plant. Examine closely details with a hand lens, then
dissecting scope, and finally use a microscope when necessary and appropriate. This will help
you keep size in perspective. For example, when you look at a leaf, examine the overall look of
the leaf, get closer and examine the vein patterns, leaf margins, and hairs with a hand lens, get a
bit closer view of interesting details using the dissecting scope, and then get really close with a
regular microscope (you might, for example, examine details of hairs).
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Right away you will notice that details in slides you prepare are usually much more difficult to
see than those in prepared slides. Overcoming the difficulty is worth it however. You will soon
© 2014 John H. Crow, Ph.D., all rights reserved
Seed Plants - Laboratory 1 - spring 2014!
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become adept at seeing the parts in any plant you pick up and will better understand how plants
are put together. You won’t be tied to purchased material and can work anywhere.
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Do not get bogged down making excruciating drawings. Prof. Crow will have run through the
'rules' in lecture before this lab. We will continue to learn how to do this in order to increase
your speed, skills, and powers of observation.
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As noted, your lab instructor may also have some prepared slides available. It is okay to look at
these but the more you use live materials the more you will really learn! Biology is the science
of living things! Botany is known as the beautiful science so, take your time and enjoy the
labs.
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© 2014 John H. Crow, Ph.D., all rights reserved
Seed Plants - Laboratory 1 - spring 2014!
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Cones and Fruits
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The seed plants Angiosperms) all have seeds, as you might expect, and all have structures that
surround the seeds. Sometimes the covering is for protection, dispersal of the seed, and so forth.
In the Gymnosperms we usually have something a bit different from what we might think of as
fruits found in the Angiosperms but there are still similarities and if one is generous with the
definition of “fruit” then we can see that the fruit is really just a covering for the seeds.
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To the right are some common “fruits.” It is easy to recognize these for what they are but at least
one example might fool you at first. More on that one later. Here, the Gymnosperm examples
have recognizable cones and the two brown objects on the left are seen as such. The large one is
from a Ponderosa Pine and the smaller one is from a Giant Sequoia, the largest living plants.
Both were collected in Sequoia National Park.
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How the cones are different from the true fruits is illustrated by the remaining 5 true
fruits? The answer is, by the way, the number one distinguishing feature separating
Angiosperms and Gymnosperms. The Angiosperm fruits illustrated are tomato, banana, corn,
apple, and a peach. Where are the seeds found in all of these examples (including the cones)?
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How about the ear of corn? Identify the fruit and identify the seed or seeds. Explain.
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Later in the semester we will study fruits in more detail but there is no reason to get off to a slow
start with respect to the basics. At that time we will carefully refine the uses of the scientific
terms and our concepts. We will see how liberties are taken by botanists with some of the most
basic terms and fruit types and how laymen use and misuse these words too.
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How would you define fruit?
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What is a seed?
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Can you think of any other type of Gynmosperm “fruit” or do they all have cones?
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Do any plants, other than Angiosperms and Gymnosperms, have seeds and “fruits?” If not how
do they reproduce? How about ferns?
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© 2014 John H. Crow, Ph.D., all rights reserved
Seed Plants - Laboratory 1 - spring 2014!
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© 2014 John H. Crow, Ph.D., all rights reserved
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Seed Plants - Laboratory 1 - spring 2014!
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Morphology
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The Superficial, External Parts of a Plant
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Some of the photos provided are examples of the terms. If I were you, I would label the photos
too. Make sketches of everything you observe.
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Sketch an entire plant. For the moment we are going to emphasize Angiosperm plants.
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Label: shoot and root, stem, nodes, internodes, terminal bud(s), axillary buds, leaves, stipules,
petiole, and blade (lamina). What is a leaf called if it has no petiole?
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Are the roots as regular as the stems in terms of brancing patterns? What are some significant
differences between roots and stems.
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Describe the types of leaves and arrangement using terms discussed in lecture.
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Arrangement of leaves: alternate, opposite, decussate, and whorled.
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Leaves: simple vs. compound
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Compound leaves: pinnate, palmate, and trifoliate are basic. We also have bipinnate, tripinnate,
and so forth.
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Now, look at the venation of leaves. We see several types: pinnate, palmate, parallel, and open.
“Open” or dichotomous applies only to one seed plant. Which one?
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Look closely at the leaves and see how the small nets are formed in all but the dichotomous
venation. Can you find any places where gases may enter and leave the plant (you will have
better luck on the underside).
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Some simple leaves are lobed. Can you suggest some names for a few of these? Leaves also
have shapes that are variously named. For example, chordate, lanceolate, ovate, etc. The tips
and bases are also named but we will not dwell on that here.
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The margins of leaves vary greatly and have particular names. A few are: entire, dentate,
serrate, crenate, serrulate, and so forth. Identify a few from the plants before you.
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Angiosperms are divided into two main groups, the Monocots and the Dicots. How are these
different. If I were to hand you a plant, could you tell me which I gave you?
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Can you see any hairs? On stems? On roots? On roots?
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© 2014 John H. Crow, Ph.D., all rights reserved
Seed Plants - Laboratory 1 - spring 2014!
For the plant to the right, what is the
leaf arrangement?
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How would you describe the leaf?
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Is there a petiole?
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Monocot or Dicot?
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Describe and label what you see to the right.
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Can you tell if this is a Monocot or Dicot?
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For the plant to the right, describe the leaf
arrangement.
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Describe the venation pattern.
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Monocot or Dicot?
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Describe the venation pattern here.
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Monocot or Dicot?
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Describe the margin.
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Describe this leaf or leaves. Is it simple or
compound?
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How about the venation pattern? What is the
margin like?
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Monocot or Dicot?
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© 2014 John H. Crow, Ph.D., all rights reserved
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Seed Plants - Laboratory 1 - spring 2014!
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Anatomy - Looking inside the Plant (herbaceous forms only in this week’s lab)
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Look at some Monocots and Dicots - Make drawings! Compare roots. Compare stems. At first,
do not try to look at all the details but look at the sections to try to recognize overall patterns and
then try to identify major tissues and areas within the sections. What is a tissue?
Some areas to note are: epidermis, cortex, vascular tissue, vascular bundles, vascular cylinder,
phloem, xylem, cambium, pith, and ground tissue.
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What differences can you see that help to distinguish between roots and stems?
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Can you see and differences between Monocot and Dicot leaves?
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Remember, materials will available on the web that supplement selected laboratories.
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Recall that the lab will continue into next week and overlap with new material. It is important to
actually see as much as possible with your own eyes and I have asked the lab instructors not to
run the labs like a lecture. Do not rely on the book but use it to help you understand the general
scheme(s) of the plant(s). Make your own observations. We will be looking for quality
observations in lecture and laboratory. Do not plan on leaving lab early. The lab is your
scheduled time to learn and if you leave early (earlier than the TA and I believe is appropriate),
you will not be given credit for your attendance in that laboratory.
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If you have questions that cannot be answered in lab, write them down and bring them to lecture.
Don’t expect your TA to know everything. We will have a general integration of lecture and lab
that will help you most of the time! Be prepared to ask and answer questions in lecture that
relate to laboratory. JHC
© 2014 John H. Crow, Ph.D., all rights reserved