Biology TEKS StudentEQ: Where are the leaves on a cactus?

Biology TEKS StudentEQ: Where are the leaves on a cactus?

Enduring UnderstandingVariations within species provide a means for adaptation and survival in a changing environment.

Plant Station LabBroad Brush Knowledgeplant structure and function; vascular/nonvascular; adaptations to diverse environmentsPlant Station LabPlant Station LabConcepts Important to Know and UnderstandBiodiversity in Plants

Targeted Skillsobservation, analyzing, making scientific drawings, making wet mount slides, correct microscope use

Targeted Skillsobservation, analyzing, making scientific drawings, making wet mount slides, correct microscope use

Core Objectives16. Analyze and categorize the characteristics of plants, recognizing their significance to living systems.

PURPOSE: To observe and learn the characteristics of plants.

BACKGROUND INFORMATION: Plants share many characteristics with green algae, including DNA, which confirms that they are closely related. Fossil evidence suggests that the first true plants were dependent on water to complete their life cycles. Over time, the demands of life on land favored plants that were not as dependent on water. Plants had to find ways to conserve water, reproduce without water, and obtain minerals. Botanists divide the plant kingdom into four groups based on three important features: water-conducting tissues, seeds and flowers. These four groups are mosses, ferns, cone-bearing plants and flowering plants.

MATERIALS: Materials will be located at each station. You will need your textbook.

PROCEDURE: Follow teacher instructions.

PLANT STATION #1Evolutionary Advances of Plants

Algae are not plants; they are protists. Algae are mostly unicellular. Some are multicellular but remain at the cellular level with no true tissues (although some have primitive “tissue-like” groups of highly specialized cells). All land plants evolved from forms of the green algae, Chlorophyta. Algae have many things in common with land plants such as cellulose cell walls and a chlorophyll-type of pigment. However, algae are not placed in the Plant Kingdom because algae do not develop from multicellular embryos which are protected and nourished for a time by tissues of the parental plant. Multicellularity with true tissues and nourished embryos are an evolutionary development of the land plants, first seen in the moss.

__________________________________1. What characteristics do algae and plants have in common? __ _________________________________________________________________________________

__________________________________2. Why are algae not considered part of the Kingdom Plantae? __ _________________________________________________________________________________ __ _________________________________________________________________________________

3. As plants evolved and moved onto land, what major obstacles did they have to overcome (see __________________________________________________________Background Information)? 1)

__ _________________________________________ 2) ___________________________________, 3) 4. What are some possible adaptations that plants developed to overcome these obstacles (p. 502-503)?

_______________________________________________________________________________1) __ _______________________________________________________________________________ 2) __ _______________________________________________________________________________ 3)

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 1

Mutualistic associations have played a key role in the initial occupation of organisms on land. Mycorrhizae are symbiotic relationships between fungi and the roots of plants. The fungus lives within the root cells. The plants provide the fungi with carbohydrates and other organic molecules made by photosynthesis. The fungi absorb from the soil phosphorous and other minerals needed by plants since the first plants lacked roots. Therefore, botanists think that these relationships may have enabled the first plants to absorb minerals from Earth’s rock surfaces. Eighty percent of all plants form mycorrhizae.

_ ____________________________________________5. Where is the mycorrhizae located in the plant? __ ___________________________________________________ Why is this a mutualistic relationship? __ _________________________________________________________________________________ __ _________________________________________________________________________________ __ _________________________________________________________________________________

_6. How do you think this evolutionary relationship played a key role in the initial occupation of organisms __________________________________________________________________________on land?

__ _________________________________________________________________________________ ___7. What are the functions of the cuticle and stomata (p. 502)?

____________________________________________________ ____________________________________________________ ____________________________________________________ ____________________________________________________ __ How do these two evolutionary advances allow plants to live on

_____________________________________________land? ____________________________________________________

Using the book, draw a stomata and guard cells showing it open, then closed

_ ________________________________8. What are the functions of xylem and phloem? (p. 507) xylem: __ _________________________________________________________________________________ __ __________________________________________________________________________ phloem: __ _________________________________________________________________________________ __ ________________________________________ How are xylem and phloem evolutionary advances? __ _________________________________________________________________________________

_ ____________________________________9. What are the functions of roots, stems and leaves? root: __ _________________________________________________________________________________ __ ____________________________________________________________________________ stem: __ _________________________________________________________________________________ __ _____________________________________________________________________________ leaf: __ _________________________________________________________________________________ __ _______________________________ Why would roots, stems and leaves be evolutionary advances? __ _________________________________________________________________________________

PLANT STATION #2Nonvascular Plants

___________________________________________________________1. Define nonvascular (p. 504). __ _________________________________________________________________________________

2. Nonvascular plants are commonly referred to as bryophytes. Three phyla of nonvascular plants are:1) _______________________, 2)_______________________, and 3)_______________________.

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 2

3. What 3 things do bryophytes lack (p. 508)?__ _______________________________________________________________________________ a. __ _______________________________________________________________________________ b. __ _______________________________________________________________________________ c.

4. Nonvascular plants transport materials by _________________ and ________________ (p. 508). _______________________________________5. These plants need a constant supply of water. Why?

__ _________________________________________________________________________________ __ _________________________________________________________________________________

____________________________________6. In what environments would you find nonvascular plants? __ _________________________________________________________________________________

____________________________7. Discuss the overall size of the bryophytes. Why are they this size? __ _________________________________________________________________________________

_______________________________________________________8. How do these plants reproduce? __ ____________________________________________________ How does the sperm get to the egg? __ _________________________________________________________________________________

_9. Examine the sample of moss under the stereoscope. __ Draw and color the moss in detail.

________________________10. Why are these leaf-like structures not considered true leaves? (p. 509) __________________________11. If nonvascular plants do not have roots, what do they have? (p. 508)

__ _________________________________________________ What is the function of these structures? __ _________________________________________________________________________________ __ _________________________________________________________________________________

PLANT STATION #3Vascular Plants

One of the characteristics of the vascular plants is that they all have tissues. There are three tissue systems that make up the vascular plant body and extend throughout the entire body of the plant. The three basic functional units, or systems, are (p 552):

1. Dermal tissue system – Covers the plant’s entire body and serves as a protective layer.2. Ground tissue system - Contains chloroplasts, performs photosynthesis, stores water and

carbohydrates, assists in transport, and surrounds and supports the conducting tissues.3. Vascular tissue system – Conducts water, mineral, nutrients, and carbohydrates made by

photosynthesis.

_____________________1. To what human body system would you compare the dermal tissue system? 2. __ What cellular organelle needed for photosynthesis is found in the ground tissue system? (p.508) ______________

________________________________________________________3. Define vascular tissue (p. 422). __ _________________________________________________________________________________ __ _________________________________________________________________________________

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 3

________________________4. What three processes work together to move water up a plant (p. 560)? __ _________________________________________________________________________________

_____________________________________________5. Define xylem (p. 554). What does it conduct? __ _________________________________________________________________________________ __ _________________________________________________________________________________

____________________________________________6. Define phloem (p. 554). What does it conduct? __ _________________________________________________________________________________ __ _________________________________________________________________________________

_____________________________7. Why would these structures allow a plant to live away from water? __ _________________________________________________________________________________ __ _________________________________________________________________________________

______________________________________8. What is the overall size of vascular plants?(p.506-507) __ __________________________________________________ Why is it different from the bryophytes?

9. Name three structures that vascular plants have that bryophytes lack. Remember vascular tissue (transport tubes) means they have:

__ ____________________________________________________________________________ a. true __ ____________________________________________________________________________ b. true __ ____________________________________________________________________________ c. true

____10. Look at the picture of the human circulatory system. How is it similar to the xylem and phloem? __ _________________________________________________________________________________ __ _________________________________________________________________________________ __ _________________________________________________________________________________

11. Xylem provides structural support for the plant. To what human body system can this be compared?__ _________________________________________________________________________________

12. Go to the stereoscope and look at the celery.__ Draw and color what you see.__ Label the xylem and phloem together as a vascular bundle.

PLANT STATION #4Roots

The first structures to appear on a germinating seed are the roots. The initial root to grow from a seed is the primary root, which is then followed by secondary roots that branch out from the primary root. In a taproot system, the primary root grows longer and thicker than the secondary roots. In a fibrous root system, the secondary roots continue to grow, and eventually all the roots are of equal or nearly equal size.

Roots anchor the plant in place, absorb water containing dissolved minerals from the environment, and act as storage areas for excess food. Adventitious roots grow from parts of the plant other than the roots. There are two types of adventitious roots. Aerial roots are roots that are suspended in the air. Prop roots grow above the ground and anchor the plant in place (p. 555).

Look at the pictures of the 4 types of roots below. Label each root by its type:

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 4

___________ ___________ ___________ ___________

1. What are three functions of roots? __ _______________________________________________________________________________ a. __ _______________________________________________________________________________ b. __ _______________________________________________________________________________ c.

_____________________________________2. What is the difference between a fibrous and a taproot? __ _________________________________________________________________________________ __ _________________________________________________________________________________ __ _________________________________________________________________________________

_____________3. Do root hairs appear to significantly increase the volume or the surface area of a root? __ ______________________________________ What benefit does this increase provide for the plant? __ _________________________________________________________________________________

_______________4. Which root is more likely to be a food source – a fibrous root or a tap root (p. 555)? __ __________________________________________________________________________ Explain. __ ___________________________________________________ Give an example of a taproot you eat.

PLANT STATION #5Leaves

Leaves are the main organs of photosynthesis in a plant. In order to produce sugars, leaves must have a way of obtaining the materials needed for photosynthesis as well as distributing its end products.In order to collect sunlight, most leaves have thin, flattened sections called blades. Leaves have an outer covering of dermal tissue and inner regions of ground and vascular tissues. The top and bottom are covered by epidermal cells. The epidermal cells are covered by a waxy cuticle on many leaves. This forms a waterproof barrier that limits the loss of water through evaporation.The vascular tissue in the leaf contains bundles called xylem and phloem. The bulk of the leaf is made of ground tissue called mesophyll. Photosynthesis takes place in the mesophyll of most plants. Air spaces called stomata (stoma is singular) are tiny openings on the underside of leaves. These allow carbon dioxide, oxygen, and water vapor to diffuse into or out of the leaf. Two guard cells expand or contract to control whether the stomata is open or closed. When water enters the guard cells, they swell and bulge so that there is an opening (stomata). When water leaves the guard cells, they shrink and relax the opening. Generally, the stomata are open during the day and closed at night (p 558-559).

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 5

Stomata may also be closed when the weather conditions are hot and dry and water conservation is needed.

_1. Use clear nail polish to paint a small section of the underside of a leaf. Allow the nail polish to dry for 10 minutes. Set aside and work on #s 2-4.

_ _____________________________________________________2. What is the main function of a leaf? __ ___________________________________________________ Why do they need to do this function?

_ _________________________________3. How are leaves protected from the excessive loss of water? __ _________________________________________________________________________________

__________________________4. What would happen to a plant if its stomata stayed open all the time? 5. Now look at the leaf with the nail polish. If the

polish is completely dry, press clear tape over it. Carefully peel the polish from the leaf by pulling gently on the tape. The polish should remain in one piece on the tape. Turn the tape so the sticky side is down and place it on a slide. Place the slide on the microscope stage. Locate the stomata on low power. Turn to high power. Draw the outline of a leaf. Draw stomata on the leaf. Count the number of stomata. _____# of stomata _____ X

6. Describe an environment where the leaves would have stomata that are closed most of the time. (think!) _________________________________________________________________________________

____________________________7. In what part of the leaf does photosynthesis usually occur? (p. 559) _____________________________8. How does the leaf get water for photosynthesis? (think! or p. 560)

__ _________________________________________________________________________________ ________________9. How does the leaf get carbon dioxide for photosynthesis? (p. 559 Last paragraph)

________________________________10. What happens to the sugars after they are produced? (p. 97) __ _________________________________________________________________________________

11. What happens to the oxygen made during photosynthesis? (Think! What do humans get from plants?) _________________________________________________________________________________

12. Look at the cross section of the leaf. Label the epidermis, cuticle, vascular bundles, mesophyll, stomata and guard cells. (p. 559)

13. Look at the pictures of different kinds of leaves at the lab station. What are some possible adaptations for the different shapes and sizes of these leaves? (p. 558-559)

TYPE OF LEAF ADAPTATION

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 6

PLANT STATION #6Primitive Vascular Plants

Fern plants are considered primitive vascular plants. They have developed many adaptations that allow them to live on land. (p. 423 and 511)

1. Name 3 adaptations that these plants have developed. (hint: Don’t write roots, stems, and leaves p.510)__ _______________________________________________________________________________ a. __ _______________________________________________________________________________ b. __ _______________________________________________________________________________ c.

_3. Jim Martin, the manager at Calloway’s plant nursery in Plano says that many people return ferns and ask for a refund. His customers lug their fern back to the store and exclaim, “This fern is sick! Look at all of these big brown spots on the back of the leaves!” Jim rarely has to provide a refund. Use Figure 3 on p. 532 to explain why he rarely has to give a refund.

__ _________________________________________________________________________________ __ _________________________________________________________________________________

__________________________4. Look at your fern. What are the rounded brown spots on fern called? _____________________________5. What is the purpose of the rounded brown spots on the fern leaf?

__ _________________________________________________________________________________

6. Draw, color and label the back of a fern leaf. Label the sporangia.

7. Put a drop of water on a slide. Take a scalpel and gently scrape the spores from the leaf onto a slide. Put a cover slip over the spores. Look at these spores under the microscope. Draw what you see.

PLANT STATION #7Gymnosperm

____________________________________________2. The word “gymnosperm” means what (p. 512)? _____________________________3. What advancements allow gymnosperms to live on land (p. 512)?

__ _________________________________________________________________________________ _____________4. Conifers are an example of gymnosperms. How do conifers conserve water (p. 513)?

__ _________________________________________________________________________________ __ _________________________________________________________________________________

___________________________5. Why are conifers not tied to water for reproduction (p.513-Figure 15) __ _________________________________________________________________________________

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 7

__ _________________________________________________________________________________ ___________________________________________6. Conifers pollinate using what type of pollination?

__ ________________________________________________ Explain this type of reproduction (p. 536). __ _________________________________________________________________________________ __ _________________________________________________________________________________

7. Conifers produce two different types of cones. Describe the two types, seed cones and pollen cones (p. 536-537). Draw each in the spaces below:Describe a seed cone. Drawing Describe a pollen cone. Drawing

_8. Look at the printed pollen grain microscope slide. Draw it in the space to the right.

__ ______________________________________ __ ______________________________________

PLANT STATION #8Angiosperms

1. Angiosperms are seed plants that have _____________________ (p. 514).2. In contrast to gymnosperms, angiosperms produce seeds that are enclosed in ___________________

(p. 514).3. The great evolutionary advancement of angiosperms is the flower. It promotes ___________________

(p. 514).___________________________________________5. Why are they not tied to water for reproduction?

__ _________________________________________________________________________________ __ _________________________________________________________________________________

You may not realize it, but you were forced to drink liquefied plant ovaries as a child! Many unsuspecting parents also feed their children squished plant ovaries. Restaurants serve pizza covered with squished plant ovaries.

________________________________________________________6. What do plant ovaries become? __________________________________7. Name one beverage that is actually liquefied plant ovaries?

_______________________________8. What type of squished plant ovaries are found in pizza recipes?

PLANT STATION #9Angiosperm specimens

What is the difference between a vegetable and a fruit? When you eat broccoli, are you eating a vegetable or a fruit? What about corn?Go to your computer and look up the following website: http://vric.ucdavis.edu/faq.htm

1. Read section 1 and define the terms fruit and vegetable.

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 8

__ _____________________________________________________________________________ fruit: __ ________________________________________________________________________ vegetable:

2. Look up the following website and read sections 1 and 2: “To Be or Not to Be a Vegetable” and “Supermarket Botany: Vegetable Anatomy”: http://waynesword.palomar.edu/plsept96.htm

3. Add to your definition of vegetables based on this information. Identify all the different parts of a plant _________________________________________________________________that are vegetables.

__ _________________________________________________________________________________ 4. Give an example of:__ _____________________________________________________________________________ fruit: __ _____________________________________________________________________________ root: __ _____________________________________________________________________________ leaf: __ ______________________________________________________________________ flower cluster: __ ____________________________________________________________________ sunflower head: __ ____________________________________________________________________________ stem: __ ____________________________________________________________________________ tuber: __ _____________________________________________________________________________ bulb:

5. Everything at this station is a fruit or a vegetable. Make a list of the fruits and vegetables. Identify them as a fruit or a vegetable. If you identify something as a vegetable, further identify what part of the plant it is from.NAME FRUIT OR VEGETABLE PART OF PLANT

PLANT STATION #10Parts of a Flower

Flowers are important in making seeds. The basic parts of a flower are the male and female parts. Flowers can have all male parts, all female parts, or a combination. Flowers with all male or all female parts are called imperfect (cucumbers, pumpkin and melons). Flowers that have both male and female parts are called perfect (roses, lilies, dandelion).

1. In the space provide below, sketch and label the parts of the flower as we learn them. Use correct labeling techniques.

2. Fill in the functions of each structure in the chart at the end of station 10.

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 9

3. Some parts of the flower that are important are the petals and sepals. Petals attract pollinators and are usually the reason why we buy and enjoy flowers. The sepals are the green petal-like parts at the base of the flower. Sepals help protect the developing bud. A receptacle holds and positions the flower. Draw petals, sepals and a receptacle on the drawing in the space above.

4. The male part of the flower, the stamen, has two parts: anthers and filaments. The anthers carry the pollen. These are generally yellow in color. Anthers are held up by a thread-like part called a filament. Draw 4 anthers and filaments on the drawing in the space above. Label the anthers, filaments and stamen.

5. The female part of the flower, the pistil , has three parts: stigma, style, and ovary. The stigma is the sticky surface at the top of the pistil; it traps and holds the pollen. The style is the tube-like structure that holds up the stigma. The style leads down to the ovary that contains the ovules. The ovules are the eggs. Draw the stigma, style, ovary and ovule above.

7. Fill in the chart below.

PARTS OF A FLOWER FUNCTION

Petals

Sepals

Receptacle

Stamen

Anther

Filament

Pistil (carpel)

Stigma

Style

Ovary

Ovule containing ovum

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 10

PLANT STATION #11Two Types of Angiosperm

Flowering plants are divided into two basic groups, monocotyledons and dicotyledons. The seeds of these groups are different, as is the development of the embryonic plant.

1. Complete the chart of characteristics of monocots and dicots. Make sketches of each characteristic (See sheet at lab station).

MONOCOTS DICOTS

Embryos- (Cotyledons) Embryos- (Cotyledons)

Vein arrangement in Leaf- Vein arrangement in Leaf-

Flower- petal and anther number Flower- petal and anther number

Vascular Bundles-roots, stems and leavesVascular Bundles-roots, stemsand leaves

Roots Roots

2. After you have completed the chart of the characteristics of monocots and dicots you are ready to identify specimens. Observe the specimens in your tray. Identify them as a monocot or a dicot. Then identify the characteristic that makes the specimen a monocot or dicot.

Specimen Monocot or Dicot Characteristic#1

#2

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 11

#3

#4

#5

#6

PLANT STATION #12Cross Sections of Roots, Leaves and Stems

At this station you will be looking at the cross sections of monocot and dicot roots, stems and leaves. Use the lowest power on the microscope for this section. (Page 552 and the few that follow might help with labeling)

1. Obtain the slide of monocot and dicot roots. Both are on the same slide. The dicot root has a cross shaped pattern at the center of the root. The xylem is the cross itself. The phloem are the smaller cells between the arms of the cross. The monocot root has vascular bundles that are in a circular pattern within the central area of the root. In the spaces to the right draw and color the cross sections. Label: Vascular bundles

Monocot Dicot

2. Obtain the slide of monocot and dicot leaves. Both are on the same slide. The dicot cross section has a thick “midrib”. Because the veins in a dicot leaf are not parallel, the vascular bundles do not have a uniform appearance. The monocot cross section does not have a thick “midrib”. Because the veins are parallel, the vascular bundles appear highly organized and uniform. In the spaces to the right, draw and color the cross sections.

Label: Vascular bundles, Mesophyll, Stomata

Monocot Dicot

3. Obtain the slide of the buttercup stem (dicot) and the slide of the corn stem (monocot). The dicot vascular bundles are arranged in a single ring around the outer edge of the stem. The monocot vascular bundles are scattered around the outer edge in a ring then scattered throughout the stem cross section. In the spaces to the right draw and color the cross section.

Label: Vascular bundles

Monocot Dicot

PLANT STATION #13Seed dispersal

Seed development was a major factor in the success of angiosperms and gymnosperms. Seeds offer protection and nutrition of the embryo. Angiosperm seeds have an advantage over gymnosperm seeds by having a fruit surrounding the seed. This fruit is instrumental in the dispersal of the seed.

1. There are four types of seed dispersal: explosive, wind, animal and water. Go to the following web site on the computer and fill in the chart. When you get to the web site, click on each type of dispersal to discover how it works. http://www.offwell.free-online.co.uk/seed_dispersl/

Plant Station Lab - Student (Revised June 8, 2004) (printed 3/21/11) p. 12

Seed Type Explanation Advantage Example Sketch

Explosive

Wind

Animal

Water

2. Look at the specimens on your lab tray and try to decide what type of seed dispersal would be involved.

Specimen Type of Seed Dispersal

# 1

#2

#3

#4

#5

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PLANT STATION #14Evolutionary Advancements

An evolutionary advancement is a characteristic or adaptation that enables the organism to better survive in its environment. There may be several correct answers, choose the best answer. (p. 509-516).

_____________________________________________1. Name an evolutionary advancement of moss. ______________________________2. Name an evolutionary advancement of seedless vascular plants.

______________________________________3. Name an evolutionary advancement of Gymnosperms. _______________________________4. Name an evolutionary advancement of seeds (p 564 and 565).

__ _________________________________________________________________________________ ____________________________________________5. Name an evolutionary advancement of flowers.

_____________________________________________6. Name an evolutionary advancement of fruits.

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