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The Diversity of Life
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Laboratory
Table of Contents
PART ONE: The Diversity of Life – Kingdom Plantae
Introduction: Diversity of and Classification ................................................................................. 1
Protista II.......................................................................................................................................... 2
Bryophytes – Non-vascular Seedless Plants .................................................................................... 5
Seedless Vascular Plants ............................................................................................................... 11
Gymnosperms ............................................................................................................................... 21
Angiosperms (Flowering Plants) ................................................................................................... 29
Plant Growth and Development .................................................................................................... 42
Plant Anatomy -- Roots.................................................................................................................. 46
Plant Anatomy -- Stems ................................................................................................................. 52
Plant Anatomy -- Leaves................................................................................................................ 66
PART TWO: The Diversity of Life – Kingdom Animalia
Kingdom Animalia I ........................................................................................................................ 1
Kingdom Animalia II ..................................................................................................................... 21
Kingdom Animalian III ................................................................................................................. 29
Kingdom Animalia IV ................................................................................................................... 41
PART THREE: Animal Form and Function
Animal Tissues ................................................................................................................................ 1
Nervous System ............................................................................................................................... 7
Senses............................................................................................................................................. 15
Digestion ........................................................................................................................................ 29
Heart............................................................................................................................................... 35
Immunology ................................................................................................................................... 39
Respiration ..................................................................................................................................... 45
Kidney, Urine Analysis and Osmoregulation ................................................................................ 57
Investigation for Concept 49.6: How do electrical stimuli affect muscle contraction? ................ 65
Reproduction.................................................................................................................................. 67
Behavior ......................................................................................................................................... 75
Investigation for Concept 50.2: How do abiotic factors affect distribution of organisms?........... 83
Investigation for Concept 53.2: How are impacts on community diversity measured? ................ 85
Investigation for Concept 50.2: How do temperature and light affect primary production? ........ 87
The Diversity of Life
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Plant Form and Function 1
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The Diversity of Life and Classification
P
lanet Earth is the only planet yet discovered which has given rise to such a multitude of living organisms.
We share this planet with wide arrays of bacteria, algae, plants, insects and other animals. Close to 3.8
billion years of evolution resulted in the diversification of organisms into a tremendous variety of shapes,
sizes and functions which allows exploitation of the different available niches. As a result of billions of years of
natural selection, organisms are adapted to particular ways of life in their peculiar environments. Today there are
over 1.6 million species which have been identified and named. This is only the tip of the iceberg; far more species
have yet to be discovered.
Studying all these organisms without a systematic and organized method would be total chaos. Therefore, a branch
of biology referred to as taxonomy, which names and classifies organisms based on distinguishing characteristics,
was developed by Linnaeus (1735). The current system of classification categorizes organisms into three domains:
Bacteria, Archaea and Eukarya. Domain Eukarya is further divided into Kingdoms “Protista” (see text book) ,
Fungi, Plantae, and Animalia. These kingdoms are further distinguished into groups within groups. This
hierarchical system of classification consists of broad categories to the more specific:
DOMAIN
KINGDOM
PHYLUM / DIVISION (for plants and protists)
CLASS
ORDER
FAMILY
GENUS
SPECIES
Furthermore, in this classification system, each organism is given a scientific name which always includes both the
genus and the species name. The following rules for writing the scientific name were developed so scientists are able
to easily recognize the scientific name. The genus is written first and capitalized, followed by the species, which is
not capitalized. The entire scientific name is either underlined or written in italics. Examples: Equus asinus or
Equus asinus (donkey); Homo sapiens or Homo sapiens (human).
2 Plant Form and Function
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Algae( Protista II)
T
he term algae, from the Latin word for "seaweed", has been used to describe simple aquatic phototrophs which
contain chlorophyll. Algae is a broad category which also can include prokaryotic organisms such as
cyanobacteria (blue-green algae).
Algae that are protists are grouped based on the predominant photosynthetic pigment :
Brown algae (phaeophytes)
Red algae (rhodophytes)
Green algae (chlorophytes)
Formerly, these algae were classified in the following phyla:
Phylum Chlorophyta (green algae)
Phylum Phaeophyta (brown algae)
Phylum Rhodophyta (red algae)
Brown algae (Phaeophytes)
This group of organisms are all multicellular, and are primarily marine and prefer colder temperatures. They are
abundant on the California and Oregon coasts. Their size ranges from small to very large, as in the giant seaweed
(kelp) found in deeper water. The stipe of kelp can grow as long as 60 meters.
Procedure: Examine a variety of preserved representatives of algae found in Southern California, and the pictures in
the botany atlas. Label the drawing below.
What is the common name of Postelsia palmaeformis? ________________________________________
What is the function of the holdfasts in brown algae? ________________________________________
What is the function of the floats? _________________________________________________________
How long can the giant sea kelp grow? ______________________________________________________
What substances give seaweed their characteristic slimy and rubbery feeling? __________________
Plant Form and Function 3
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Red algae (Rhodophytes)
Red algae are primarily marine. They are more abundant in warmer temperatures, and can be found at the deepest
depths for algae, up to 250 meters below the surface of the ocean. They contain chlorophyll, but the more abundant
pigment is a red pigment called phycoerythrin, which masks the green pigment. The majority of red algae are
multicellular.
Procedure: Examine a variety of preserved representatives of algae found in Southern California, and the pictures in
the botany atlas.
Carefully study Carolina algae as one representative, and make a drawing.
What is the substance that makes their appearance more like coral?
Green algae (Chlorophytes)
Green algae are primarily found in fresh water. Different types include unicellular, filamentous , colonialand
multicelluler, as well as motile and non-motile. Green algae are considered to be the most closely related to
terrestrial plants. Green algae are divided into two main groups: chlorophytes and charophytes.
Chlorophytes
There are more than 7,000 species identified. The majority live in fresh water, however there are also marine and
terrestrial species.
Single-Celled Chlorophytes
Organisms belonging to the genus Chlorella are single-celled green algae. [Chloros is Greek for green, and ella is
Latin for small.] The cells are spherical and do not have flagella.
Procedure: Obtain a prepared slide of Chlorella, and draw it below.
Chlorella [430X]
Colonial Representatives
4 Plant Form and Function
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Volvox is a colonial algae composed of several hundred to tens of thousands biflagellate cells.
Procedure: Obtain prepared slides of the organisms below. Draw, and label the structures.
Volvox 100 X
[motile, colonial, made up of several hundred to
60,000 bi-flagellated cells] [Atlas Figure 35b]
Hydrodictyon 430X
[water net]
[Atlas Figure 35f]
Volvox: Volvox develop daughter colonies.
Is that an example of sexual or asexual reproduction? ___________________________________
Explain how Volvox undergoes sexual reproduction. Draw the life cycle.
Plant Form and Function 5
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Spirogyra are filamentous green algae commonly found in green masses on the surface of ponds.
Spirogyra vegetative 400X
[Atlas Figure 36a]
Spirogyra:
Spirogyra sexual 400X
[Atlas Figure 36c,d,e]
What is the shape of the chloroplasts? ________________________________________
How are they arranged within the cell? ________________________________________
6 Plant Form and Function
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Closteridum 250X
[Atlas Figure 37d]
Oedogonium 400X
[unbranched, filamentous green algae]
[Atlas Figure 38a,b,c]
Micrasterias 250X
[Atlas Figure 37g]
Plant Form and Function 7
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Multicellular Green Algae
There are approximately 400 species of charophytes. These multi-cellular
algae are considered to be the closest relatives to organisms belonging to
Kingdom Plantae, based in part on the similarities in pigment composition.
Chara inhabits fresh water. It is known as stonewart due to the fact that
the plant can become encrusted in calcium carbonate (lime). It is also
sometimes referred to as musk grass or skunkweed due to its garlicky
odor.
Procedure: Obtain a prepared slide of Charai, and draw it below. Distinguish the oogonium (containing eggs) and antheridium
(containing male gametes).
Chara w.m. [430x]
Chara c.s [430x]
In addition to the composition of pigments, list three other characteristics (mentioned in the textbook) that
provide evidence for their close relationship to Kingdom Plantae.
Look at the other, non-microscopic representative samples of green algae on the side counter.
For more information on algae in California, go to the web site:
http://www.sonoma.edu/biology/algae/algae.html
8 Plant Form and Function
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Review Questions
Matching. Each question may be matched with one or more than one answer. Answers may be used once, more
than once or not at all.
1. ________ Red algae
2. ________ Green algae
3. ________ Brown algae
4. ________ Spirogyra
5. ________ Volvox
6. ________ Multicellular, attains great size and
complexity
7.
a.
b.
c.
d.
e.
Chlorophyta
Rhodophyta
Phaeophyta
Colonial algae
Filamentous algae
At what depth is each type of algae found?
Depth
Type of algae (red, brown, green)
Shallow water
_______________
Medium depth
_______________
Deep water
_______________
How is it possible for some algae to live at great depths where there is little light? Explain.
8. From which algal phylum did green plants most likely arise? Explain the evidence supporting this hypothesis.
Plant Form and Function 9
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The Diversity of Life - Kingdom Plantae
Bryophytes - Non-vascular Seedless Plants
ryophytes (from Greek bryon - “moss”) are plants that grow in moist habitats. Included in this group are
mosses, liverworts, and hornworts. The oldest known fossil of moss is about 350 million years old.
Bryophytes are not fully adapted to dry land for two main reasons. Their sperm must swim through water to
fertilize the egg. In addition, because they generally lack vascular tissue (xylem and phloem), they depend on the
surrounding water to transport fluids and minerals necessary for growth. Thus, none of the species becomes very
large, although some may form extensive low mats.
B
Phylum Bryophyta: Moss
Procedures:
Examine the preserved samples on the side counter showing:
Four different species of moss
Observe the differences in shape, etc.
Label the examples below with the correct name: Sphagnum, Mnium, Polytrichum, Funaria
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The life cycle
Be able to distinguish the gametophyte and sporophyte
and the sporangium (contains spore).
Label the identified structures.
generation,
Examine the slides of moss (Mnium) antheridia and archegonia (plural of archegonium) under low power (40X) and
high power (100X). Label the indicated structures on the microscopic images below and on the next page. [Atlas
Figure 45b]
gametophyte
Longitudinal section of moss antheridial head - 40X
Plant Form and Function 11
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Moss archegonial head l.s.- 100X
[Atlas Figure 45d]
Moss archegonium l.s. - 400X
[Atlas Figure 45e]
Draw and label the parts of the moss life-cycle below.
Moss life-cycle. On the gametophytes, which are haploid, the
sperm are released from antheridia. They then swim through
free water to the archegonia and down their neck to the egg.
Fertilization takes place there; the resulting zygote develops
into a sporophyte, which is diploid. The sporophyte grows on
the gametophyte and eventually produces spores as a result of
meiosis. These spores are released and germinate, giving rise
to gametophytes. The gametophytes initially are threadlike;
they grow along the ground. Ultimately, buds form on them,
from which leafy gametophytes arise.
Phylum Hepatophyta: Liverworts
Liverworts are often only slightly more complex than marine algae, thus they are considered to be one of the simplest
photosynthetic plants found on land. Liverworts do not have roots, but have filaments called rhizoids which are used
to absorb water and nutrients.
Examine the preserved sample. Identify the genus of the liverwort shown below and label the indicated parts.
12 Plant Form and Function
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Plant Form and Function 13
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Questions:
1. Why is the term “gametophyte generation” used to describe this stage of the moss life cycle? Is it haploid or
diploid?
________________________________________________________________________
2. Why is the term “sporophyte generation ” used to describe this stage of the moss life cycle? Is it haploid or
diploid?
________________________________________________________________________
3. Are archegonia male or female reproductive structures?
4. Are antheridia male or female reproductive structures?
_____________________
_____________________
5. Do the sperm get to the eggs by way of (a) wind or (b) swimming in water?
6. Do Bryophytes reproduce sexually via: (a) seeds or (b) spores?
7. Are spores haploid or diploid?
_______________________
8. In addition to reproduction, spores facilitate ___________________ of the organism.
(a) water intake
(b) anchorage
(c) dispersal
Engage Your Mind and Discover Your Knowledge:
1.
The genus Sphagnum in mosses is considered to be the most primitive of the mosses. Common names include:
bog moss, turf or peat moss. This type of moss is aquatic or semiaquatic, and grows in dense masses in swamps,
ponds or at lake margins. During growth, certain acids are liberated, causing the surrounding water to become
acidic (pH levels from 3.7 to 4.8).
What possible effects would the release of acid have?
How can this be advantageous to the mosses?
14 Plant Form and Function
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Plant Form and Function 15
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The Diversity of Life - Kingdom Plantae
Seedless Vascular Plants
T
he next group of plants to evolve after the bryophytes were seedless vascular
plants. Ferns are the most familiar seedless vascular plants. Unlike the
bryophytes, the ferns do possess vascular tissue (xylem and phloem) and
true roots, which makes them capable of transporting great quantities of water
and minerals over long distances in short periods of time. The presence of these
conductive tissues allow this group of plants to grow more upright and larger than
moss. The seedless vascular plants are grouped into two phyla: Phylum
Pterophyta (e.g., whisk ferns, horsetails, and ferns) and Phylum Lycophyta (e.g.,
club moss, spike moss, and quillworts).
Phylum Pterophyta
Ferns
Draw and label the life-cycle of the typical fern.
Fern life-cycle. The gametophytes, which are haploid, grow
in moist places. Eggs and sperm develop in archegonia and
antheridia, respectively, on their lower surface. The sperm,
when released, swim through free water to the mouth of the
archegonium, entering and fertilizing the single egg.
Following the fusion of egg and sperm to form a zygote -- the
first cell of the diploid sporophyte generation -- the zygote
starts to grow within the archegonium. Eventually, the
sporophyte become much larger than the gametophyte--it is
what we know as a fern plant. On its leaves occur clusters of
sporangia, within which meiosis occurs and spores are formed.
The release of these spores, which is explosive in many ferns,
and their germination, lead to the development of new
gametophytes.
Examine the lower surface of a typical fern leaf on the side counter. Note the brownish sori (singular = sorus). Each
sorus contains many sporangia (singular = sporangium) where the spores are produced. Notice the difference
between the ventral (lower) and dorsal (upper) view.
What is stored or will be released from sporangium?
__________________________
What is the chromosome component (i.e., haploid or
diploid) of the sporangium cells ?
__________________________________________
Are the spores haploid or diploid?
__________________________________________
Lower surface of a typical fern leaf
Examine the preserved life history of the fern under the dissecting microscope on the side counter or with a hand
lens. Distinguish the various stages and possible structures and compare with the drawing of the life cycle.
16 Plant Form and Function
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spores
prothallium
sporophyte
Life history of fern
Examine the slide of the fern prothallium (heart-shaped structure) using a compound microscope under low power
(prothallium) and high power (antheridia and archegonia).
Fern prothallium - 100X
Plant Form and Function 17
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Look at the display of different species of fern. Try to match the following pictures with the displays. Write down
their names: Sword fern (Nephrolepis exaltata,) Autumn fern (Dryopteris erythrosora), Leatherleaf fern (Aspidium
capense) , Asparagus fern (Asparagus densiflorus).
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Plant Form and Function 19
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CALIFORNIA PLANTS
Observe the drawings and any preserved samples, and read the descriptions of some ferns found in California
habitats.
Select four species of ferns common to California. Draw the frond (leaf) of each in a box below and complete the
corresponding information.
Common name: ___________________________________
Scientific name: ___________________________________
Elevation/ Area found: _____________________________
________________________________________________
Unique characteristics/interesting facts: ________________
_________________________________________________
_________________________________________________
_________________________________________________
Common name: ___________________________________
Scientific name: ___________________________________
Elevation/ Area found: _____________________________
________________________________________________
Unique characteristics/interesting facts: ________________
_________________________________________________
_________________________________________________
_________________________________________________
20 Plant Form and Function
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Common name: ___________________________________
Scientific name: ___________________________________
Elevation/ Area found: _____________________________
________________________________________________
Unique characteristics/interesting facts: ________________
_________________________________________________
_________________________________________________
_________________________________________________
Common name: ___________________________________
Scientific name: ___________________________________
Elevation/ Area found: _____________________________
________________________________________________
Unique characteristics/interesting facts: ________________
_________________________________________________
_________________________________________________
_________________________________________________
Plant Form and Function 21
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Some Interesting Facts - Match the facts below with the correct species.
___ 1. The Miwok Indians used rhizomes from which
California fern for brown fibers in their baskets?
___ 2. Indians used the root stalk and
young tender fronds for food.
a.
b.
c.
d.
Maidenhair fern (Adiantum jordani)
Bird’s-foot fern (Pellea mucronata)
Brake or Bracken fern (Pteridium aquilinum)
Woodwardia or Giant Chain Fern
(Woodwardia fimbriata)
___ 3. When sheep and goats eat the wiry stalk of this fern,
it results in death -- the stalk breaks into sharp pieces
which pierce the intestines.
___ 4. Early white settlers made summer shelter with their fronds.
___ 5. Which fern is the most commonly found in the Sierras?
Phylum Pterophyta
Horsetails
Horsetails are another representative sample of Phylum Pterophyta. This group of organisms was abundant in the
tropical regions about 300 million years ago. Horsetails have hollow, jointed stems and true roots. The stem
contains silica, which give them a grainy texture. Furthermore, the green stem is the main organ of photosynthesis.
The reproductive branch of the horsetail bears a terminal conelike strobilus which contains sporangia that will give
rise to spores. Horsetails grow to less than 1.3 meters (4 feet). Horsetails are commonly used in water gardens.
Examine the representative sample of horsetails and label the picture below.
What is the function of the strobilus? ___________________________________
22 Plant Form and Function
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Phylum Pterophyta
Whisk Ferns
The whisk ferns are highly specialized plants that have
evolved recently. Whisk ferns are simple vascular plants
lacking roots. They can be found in the tropics and
subtropics.
Observe the sample whisk fern and note its
Distinguish the tiny round sporangia that may be present
on the erect stems. These produce haploid spores.
sporangia
characteristics.
Phylum Lycophyta
Club Mosses, Spike Mosses, Quillworts
There are 1,200 species of lycophytes today. Even though some are referred to as club or spike “moss”, they are
vascular plants and not true mosses.
Study the representative samples and note their characteristics.
Plant Form and Function 23
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Review Questions : Phlym Bryophyta and Phylum Pterophyta
1. What is meant by "alternation of generations"? What two generations are involved? How does each reproduce?
2. What structures are found in Bryophytes that are not found in algae?
3. What structures are found in ferns that are not found in Bryophytes?
4.
How do Bryophytes absorb water and minerals?
5. What are the factors that make Bryophytes and ferns dependent on "free" water (water surrounding the plant)?
6. Which of the following have true roots? FERNS
MOSS
HORSETAILS
WHISK FERN
7. What structures or characteristics allow ferns to grow large, up to 8 meters tall, such as in the case of tree ferns?
24 Plant Form and Function
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Plant Form and Function 25
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Gymnosperms
T
he plants we have studied thus far (Bryophytes and ferns) are plants that are adapted to moist and cool
environments. More than 200 million years ago, these plants were the dominant plant-life on earth. Then 150
million years ago, temperatures started warming and as a consequence more dry land was available, presenting
opportunities for the development of plants with different sets of structures to overcome the new challenges. Thus,
evolutionary forces launched a new group of plants – plants that bear seeds.
Gymnosperms
Gymnosperms are non-flowering plants that produce seeds. The word gymnosperm comes from two Greek words
that mean "naked-seeded," which alludes to the fact that most, but not all, gymnosperm seeds are produced out in
the open on cone scales, whereas the seeds of angiosperms (flowering plants) are produced completely enclosed
within a fruit.
Gymnosperms encompass four phyla:
Coniferophyta
Cycadophyta
Ginkgophyta
Gnetophyta
Gymnosperms
A.Phylum Cycadophyta
There are 140 living species in Phylum Cycadophyta. These organisms were widespread during the age of
dinosaurs. This plant has leaves that are palm-like and the common name of one species is sago palm,
however, don’t let the name throw you off: cycads are gymnosperms while palm trees are flowering plants
(angiosperms).
During World War I, due to food shortages, people on Guam ate the seeds of the cycad, and
developed severe muscle spasms. It is now known that the seeds contain neurotoxins and carcinogenic
compounds.
Draw a typical leaf of a cycad.
26 Plant Form and Function
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B.Phylum Ginkgophyta
This phylum of plants was thought to be extinct, yet a group of Ginkgo biloba (Maidenhair) trees was found
in China. This is the only living member of this phylum. These graceful trees with their fan-shaped leaves
have become popular in landscaping due to their resistance to disease and air pollution.
The trees are dioecious and deciduous.
Observe the Ginkgo branches and the preserved specimens.
Label the structures of the Ginkgo shown below.
Smell the fleshy seed of Ginkgo. Describe the distinct odor.
___________________________________________________________
If you were going to plant a Ginkgo biloba in your yard, would you plant a male or female
tree? Why?
__________________________________________________________
C.Phylum Gnetophyta
There are 70 species in this Phylum, one of which is in California (Mormon tea). They are normally found
in hot climates, either tropical or desert. It has recently been shown that these plants are most closely
related with flowering plants.
Look at the pictorial samples on the side counter. Note some of the characteristics.
What is the genus of the plant which is known as Mormon tea? ___________________
Plant Form and Function 27
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D. Conifer
(Phylum Coniferophyta)
Conifers are the most abundant of the Gymnosperms. They are characterized by scale-like or needle-like leaves
which are adaptations to cold and dry environments. These majestic creatures include individuals which reach aweinspiring heights of 117 meters or more (Coastal Redwoods), and phenomenal ages (the oldest known bristlecone
pine is 4,725 years old).
ON THE SIDE COUNTER, OBSERVE THE MALE AND FEMALE CONES.
The pine trees produce two kinds of cones -- female (megasporophyll or seed cone) and male (microsporophyll or
pollen cone). Female pinecones usually take two growing seasons to mature. Notice the paired winged seeds at the
base of each cone scale. It is possible that the seeds are missing, if so, the slight depressions in which the seeds
rested should be discernible.
Examine and explain the differences in the structures. Be able to recognize male and female cones.
___________________________________________________________________________________
Apart from the size differences, how can you distinguish a female pinecone from a male pine cone?
___________________________________________________________________________________
Female Cones
Sugarpine
Ponderosa
Pine
Coastal Redwood
wing
Fir
Giant Sequoia
seed
Male Cones
28 Plant Form and Function
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Examine the prepared slide of a male pine cone
(Pinus staminate cone). Label the pollen grains
and microsporangium (pollen sac).
Male pine cone(l.s.) 40X
[Atlas Figure 55c]
Prepare a wet mount slide of pollen. Observe
under high power. Label the structures.
Does this remind you of any cartoon figure?
________________________
Pollen 400X
In this group of organisms pollination is aided by _____________ .
[insects / bats / water / wind ]
What do the pollen grains of pine trees have that aid in their dispersal?
__________________________________________________
Plant Form and Function 29
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Examine the prepared slide of a female pine cone
(megasporangium) l.s.. Draw and label
ovuliferous scale, ovule.
Female pine cone 40x
[Atlas Figure 56c]
Examine the prepared slide of a Pinus mature
embryo (l.s.). Draw and label: female
gametophyte, embryo, cotyledons
Pinus mature embryo
[Atlas Figure 57d]
Draw and label the life cycle of a pine.
30 Plant Form and Function
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Identification of Organisms and Construction of Dichotomous Key
People often depend on biologists to identify organisms that they may encounter. Experts in a particular field may
know the names of local organisms, but no biologist can remember or learn all the features which distinguish
different species, or their names. Biologists have developed dichotomous keys via keen observations and patience,
utilizing distinct characteristics to systematically narrow down the possible identification of an organism to the
species level.
A dichotomous key uses a two-branch system in which two choices are given at each level. Each of these two
choices provides unambiguous questions to further separate and distinguish the organisms. Through this continuous
series of binary choices, one can reach the proper identification. A key should be precise, simple, and easy to use.
For example, if you have eight objects of four shapes, different sizes and two colors, a possible key would look
something like this.
KEY TO 8 OBJECTS
1a. If it’s red, go to ................................................................ 2
b. If it’s not red, go to .......................................................... 5
2a. If it’s a circle, go to ........................................................... 3
b. If it’s not a circle, go to ..................................................... 4
3a. If the diameter 15 cm, it is .............................. “Object A”
b. If the diameter < 15 cm, it is ............................. “Object B”
4a. If it’s a square, it is ............................................ “Object C”
b. If it’s a triangle, it is .......................................... “Object D”
5a. If it’s a rectangle, go to ..................................................... 6
b. If it’s a circle, go to ........................................................... 7
6a. If the length > 29 cm, it is ..................................“Object E”
b. If the length  29 cm, it is ................................... “Object F”
7a. If the diameter = 5 cm, it is ............................... “Object G”
b. If the diameter = 19 cm, it is ............................. “Object H”
To better understand the process and the use of dichotomous keys for identification purposes, you will construct your
own dichotomous key for a group of conifers provided to you. The goal is for anyone to be able to use your key to
determine the species of an unknown plant. In addition, creating a key helps you to sharpen your observation skills,
and at the same time become more familiar with characteristics of common conifers in California.
Plant Form and Function 31
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Study the specimens of pine branches and cones. With your keen observations, distinguish all the characteristics and
differences among the samples provided. The names of the plants are provided. Your task is to develop a
dichotomous key that allows any individual to key out these plants and determine their identity. Pay attention to
such characteristics as: number of needles in a bundle, size of leaves, type of leaves (needle-like, scale-like), size of
the cone, fleshy seeds, color, etc.
Common name/
Scientific name
(if available)
Description of leaves
Description of cones
Other observations
32 Plant Form and Function
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KEY for Samples of Conifers
Plant Form and Function 33
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It is not essential to know the names of all the California pines, however you should be able to distinguish cypress
from juniper and other pines by recognizing distinct characteristics.
Explain the distinct characteristics of cypress.
Explain the distinct characteristics of juniper.
34 Plant Form and Function
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REVIEW QUESTIONS
1. How are gymnosperms better adapted to terrestrial living than the plant species (fern, moss) you examined
in the last lab?
2.
What is the evolutionary importance of wind-pollination?
3.
What are two different ways in which conifers disperse their seeds?
4.
What are some of the important evolutionary adaptations of Giant Sequoias?
5.
What do botanists mean when they use the terms dioecious and monoecious? Give examples of each.