Field Trips

Plant Adaptations

Grade Level:
Upper Elementary: Third Grade through Fifth Grade
Subject:
Science
State Standards:
Strand 4.1: ORGANISMS FUNCTIONING IN THEIR ENVIRONMENT.
Standard 4.1.1 Construct an explanation from evidence that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.

Essential Question: How do desert plant parts (internal and external structures) help them survive in some places better than others?

Utah Science with Engineering Education Standards:

Strand 4.1: ORGANISMS FUNCTIONING IN THEIR ENVIRONMENT. Through the study of organisms, inferences can be made about environments both past and present. Plants and animals have both internal and external structures that serve various functions for growth, survival, behavior, and reproduction.
Standard 4.1.1 Construct an explanation from evidence that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction. Emphasize how structures support an organism’s survival in its environment and compare the internal and external structures of plants and animals within the same and across various Utah environments.

Background
Desert plants are adapted to their arid environment in many ways. Small leaves on desert plants help reduce moisture loss during photosynthesis. Small leaves mean less evaporative surface per leaf. In addition, a small leaf in the sun doesn’t reach as high a temperature as a large leaf. Leaves and stems of many desert plants have a thick, waxy covering, keeping the plants cooler and reducing evaporative loss.

Some plants, such as Ephedra (Mormon tea) and cacti, carry out most or all of their photosynthesis in their green stems. Cactus pads are stems. Other desert plants grow leaves during the rainy season and then shed them when it becomes dry again. These plants, such as blackbrush, photosynthesize in their leaves during wet periods and in their stems during drought. Spines or hairs shade plants and break up drying winds across the leaf/stem surface.

The roots of desert plants are also adapted to help them survive. Some plants have shallow, widespread roots to absorb a maximum of rainfall moisture. Others have deep taproots to get water that is deep underground.

Plants use many mechanisms for seed dispersal, but they can be broken down into four broad categories: wind dispersal, water dispersal, external “hitchhikers”, and internal “hitchhikers”. Wind-dispersed seeds are often very light with large surface areas or cotton-like “puffs” to help them catch the wind and travel. Cottonwood “puffs” and maple “helicopters” are two very common wind-dispersed seeds. Water-dispersed seeds often have a seed coat that is very light and porous to increase buoyancy and help the seed float on waves or currents. For example, the outer husk of a coconut is very light and helps it float in the ocean.

“Hitchhiker” seeds rely on animals for dispersal. External hitchhikers usually have hooks, spines, or sticky substances to help them attach to an animal as it brushes by the parent plant. After a while, the seed will fall, often miles from the parent plant. Instead of relying on animals to brush against them, plants with internal hitchhiker seeds actively try to get animals to eat their seeds by enclosing them in a nutritious, good-tasting fruit. Inside the animal’s body, the outer fruit is digested, but the seeds are untouched. When the animal eliminates its solid waste, the seeds are dropped miles away from the parent plant along with a pile of natural fertilizer to help them grow.

Riparian zones are the areas bordering rivers, streams, and lakes. They often appear as a greenbelt with a variety of plants that are adapted to the abundance of surface water and the shallow water table. Extra moisture in riparian zones combined with an abundance of vegetation creates a relatively damp, cool area where plants can thrive. Decomposing plant matter enriches the soil, furthering plant growth.

In the western United States, riparian areas comprise less than 1 percent of the land area, but they are among the most productive and valuable natural resources. In Utah, the water-rich riparian areas and arid uplands are significantly different. Riparian areas are the major providers of habitat for endangered and threatened species in the western desert areas.

Plants that live in the riparian zone have adaptations that allow them to survive flash floods, saline soils, and being eaten by the animals coming to the area for water. Cottonwood trees grow tall to protect their leaves from browsing animals. Their thick trunks and deep roots protect them during floods. Adult trees lose enough water through evapotranspiration every day to fill the back of a pickup truck. Willows are flexible, allowing them to bend rather than break during flood events. When willow branches break, then easily reroot downstream. Tamarisk take advantage of salty soils by concentrating salt in their leaves and then dropping those leaves so that the surrounding soil becomes more saline than other plants can tolerate.
 

Cacti - Cactus pads are modified stems with a waxy coating. Their root system is very shallow, drinking up ephemeral rainwater. Small rain roots can grow as soon as soil is moistened. Prickly spines are modified leaves that break up the evaporative winds blowing across pad surfaces and can help shade the stem. Cacti utilize CAM photosynthesis, in which stomata open only at night when the plant is relatively cool, so less moisture is lost through transpiration. Gases, including carbon dioxide going in and oxygen going out, pass through the stomata as well. This gas exchange is part of the process of photosynthesis. But, photosynthesis also requires sunlight. The CAM process includes a way of chemically storing the carbon dioxide until the sun comes out, when it can be used to complete the photosynthetic process. (A stoma is like a window; it must open to let air and water in or out, but sunlight can come in even if it’s closed.)

Juniper - Leaves are reduced to tiny, waxy scales that cover the twigs and small branches. Fruits are also covered with a waxy coating. Junipers can cut off water to a major branch during a drought, leaving a dead branch but allowing the tree to survive.

Sagebrush - Hairy leaves insulate this plant against heat, cold, and dry winds. Retaining its leaves year-round allows the plant to produce food most of the year. Sagebrush has adaptations to cold winters; it can photosynthesize when temperatures are near freezing, and its leaves point in all directions, allowing them to catch sunlight from many angles.

Single leaf ash – Unlike other ash trees, the single leaf ash only has one leaf per stem, which helps it to survive in hot, dry environments. Fewer leaves mean less surface area and less water loss through evaporation.

Ephedra – Ephedra’s segmented stems are photosynthetic which allows them to produce only tiny inconspicuous scale-like leaves. The stems can be used to a medicinal tea from the stems which can be used to treat colds and congestion. The drug ephedrine comes from Ephedra chinesis, a close relative of the species that grows in Southern Utah.

Moonflower – Also known as Datura or Jimsonweed. It produces large funnel shaped white flowers which open in the evening to attract moths. Moonflower is toxic to both humans and animals. While jimsonweed can be used to cause hallucinogenic visions, it can be fatal if ingested.

Cottonwood - Cottonwood trees often grow 50-60 feet tall with a trunk diameter of 3 feet. While a single tree can consume 50- 200 gallons of water a day, these tall trees can survive with little rain because their roots stretch deep into the groundwater. During late spring, their seeds fly through the canyons attached to white fluff or “cotton”. Since their seeds prefer to germinate in sandy riparian soil, and torn branches root easily, cottonwoods are often viewed as an indicator of fresh water. Their deep roots and thick trucks stabilize the trees during flash floods.

Willow – Coyote willows are often the first plants to colonize flood deposits where moisture and full sun are consistent. Their flexible branches allow them to bend during floods, and if broken, branches root into wet soil wherever they are deposited.

Procedure

Plant Structures and Functions

Objectives: Students will be able to:           
a. Name the main structures of a plant and their function.

Essential Question: How do the structures of a plant help it achieve its functions?

Materials: 6 or 7 weeds showing roots and flowers (per class); hand lenses; two different kinds of water bottles (i/e a clean canteen and a bike bottle); structure and function cards (4 card colors); structure and function (4 colors)

Procedure:
1) Ask students to think of some plants that grow in the schoolyard or about plants in their yard or garden at home. Ask the students what plants need to do to survive? Write the students’ ideas on the board; then narrow it down to four primary functions of plants: getting water, making food, making seeds/reproducing, and avoiding getting eaten. (2-3 min)

2) Distribute hand lenses and remind students how to use them. Divide students into groups and give each group a plant to examine. Tell students they may see these plants in their yards, and that they are considered weeds, so it was okay to kill them by pulling them out of the ground. Encourage students to look for the parts that are green, identify different parts of the plant, and examine each part’s size and shape. After a few minutes, have groups switch plants. Encourage students to compare similarities and differences. If time, switch plants again. Collect the plants. (10 min)

3) Introduce the concept of structure and function. Show students two different kinds of water bottles and ask them to describe their characteristics. Discuss how the purpose, or the function, of both water bottles is the same: to carry water from one place to another. However, the bottles have different structures: one may be plastic, one may be insulated, one’s lid may allow sipping. Describe how one structure may be better than another for different activities. For example, an insulated bottle would keep ice cold on a hot day, but not be so good for a bike ride. A bike bottle would be easy to drink while riding, but it won’t keep water cold. Every plant has parts that accomplish the same functions. Roots suck water from the ground, leaves make sugar, etc, but the structures may be different. Ask if the plants students examined all had the same roots or the same leaves. Just like the different structures of water bottles made them better for one activity or another, different structures on plants can help them accomplish their functions in different environments. (3-5 min)

4) Draw a simple plant diagram on the board and label its structures: roots, stem, leaves, and flowers. Tell students their next task will be to match the structures of several plants with their functions and discover what the parts do to help the plant survive. Show students an example of the poster and place posters around the room. Distribute all the structure and function cards. If a student is given two cards, make sure both cards are the same color. Invite students to get up and find the people who match their color and structures and functions to complete the sentences on the poster. For example: the blue “Leaf” would match with blue “sunlight” and ‘sugar.” Once students find their match, they should go to their same color poster and attach their structures and function cards. (5-7 min)

5) Have students return to their seats and use their posters to review plant structures and their functions. (5 min)

Desert Plant Adaptations

Objectives:
a. Name three desert plant adaptations
b. List 2 factors that make life in the desert challenging for plants

Essential Question: What structures allow plants to conserve water?

Materials: 7 plant part cards with structures labeled (different species); Adaptation cards (7); structure/function poster and velcro structure/function cards; whiteboard; dry erase marker; soil moisture gauge; temperature gauge

Note: Adaptation cards must be hidden in advance in scavenger hunt area; place moisture gauge nearby to read.

Procedure:
1) Have students observe the habitat around them for 30 seconds. Encourage them to find different sizes, shapes, and colors in the plants. Discuss their observations and characteristics of the desert that make it difficult for plants to grow. For example, deserts are dry, windy, hot in the summer, and lots of animals may eat the plants. To support their ideas, collect data about the environment by observing the moisture gauge and taking 4-5 temperatures. If students already attended the riparian station, compare similarities and differences to a riparian area. To survive in the desert, plants try to lose as little water as possible. Invite students to suggest adaptations or ways plants might store and slowly use water so they can survive in the desert. (5-7 min)

2) Show students a plant part card and explain the name of the plant, its picture, and labels of plant parts with arrows. Hand each student a plant part card and give them a minute to read their card and make observations. Stress that students should pay attention to arrows pointing to labeled plant parts. Students should then compare their cards with a partner. Encourage them to notice how the plants are different sizes, shapes, and colors, but the parts are the same (flower/fruit/seed, leaves, stem, and roots). Invite students to share their observations. Review how plants have the same structures, but structures can look different because plants have different adaptations. Clarify that adaptations are changes to structures that help plants better survive in their habitat. Encourage students to feel the waxy leaves of the juniper tree and discuss how the waxy coating helps prevent water loss. Point out the cactus spines, and tell students spines are the leaves and the pad is the stem. Encourage students to find the stem of the ephedra and discuss its lack of leaves. (3-5 minutes)  

3) Show students the structure and function poster. Lay out label cards and match the structures and functions as a group. Invite students to attach labels to the poster. Distribute labels to students and review the function of each part as students attach their label, adding pertinent information. When the leaf label is attached, ask if students remember the science word for plants absorbing sunlight and making sugar. Stress green color helps the plant to absorb energy from the sun. If you see green on a plant, you know that part does photosynthesis. Green also means a plant is alive. (5 min)

4) Challenge students to find examples of the plants on their plant part cards. Give boundaries and tell them one example of their plant has an adaptation card hidden in it. When students find their plants and adaptation cards, they should stand next to their plant until everyone has found their plant. (5 min)

5) Invite students to introduce their plant and read its adaptation or have you read its adaptation. When you get to prickly pear, review the function of the leaves/spines. Ask students to observe the color of the spines and discuss that an adaption of cacti is that the stem absorbs sunlight. Review these ideas when observing the ephedra. Stress how the plants have the same structures (leaves, stems) but some are adapted to do different functions. (7-10 min)

6) Ask students if a seed from a plant that usually lives in a riparian area, without desert adaptations, could survive long enough in the desert to reproduce. Discuss why. Tell the students occasionally a plant sprouts with something different about it. If this trait helps the plant, the trait is passed down to its seedlings. If it does not help, the plant may not survive to reproduce. Each of the plants in the desert, at one point or another, gained adaptations, which made them more likely to survive than the plants without these adaptations. Ask students to place the cards back where they found them. (3-5 min)

Adaptations to note:

 

Flower/fruit/seed

Stem

Leaf

Root

Juniper

Waxy berries

Water distribution to branches

Waxy (prevent water loss)

 

Yucca

Tall stalk

 

Pointy (protect)

Really deep taproot

Prickly Pear

 

Pad photosynthesizes/ stores water;Waxy

Spine (protect)

Shallow and stretched out wide from plant

Sagebrush

 

 

Hairy (water loss);Very light colored;Small leaves

 

Ephedra

 

Photosynthesizes

Very reduced

 

Plant Questioning
(Adapted from Beetles Project “Interview an Organism”)

Objectives: Students will be able to
a: Identify at least two structures of a plant
b: Formulate at least one scientific question about the function of the plant’s structure

Essential Questions: How do questions help us examine the relationship between plants’ structures and their functions for survival in the desert? What functions do the structures of desert plants support?

Materials: Hand lenses; worksheets (including an example one filled out); clipboards; pencils; plant ID guide; question sentence stems poster

Procedure:
1) Observe and discuss plants while walking to the station. Once at the station, ask students if they have a favorite plant. If they do, invite students to share their favorite plants. Discuss how their favorite plants differs from the surrounding plants. Pick one of the favorite plants students named or share your own. Ask students to name a structure of this plant and guess its function. For example, a rose has a structure called a thorn that functions to protect it from herbivores. A rose also has a flower, a structure which functions to make seeds. (5-7 min)

2) Tell students that they will get to choose and investigate their own favorite plant in the desert habitat. Establish boundaries and allow the students about 2-3 minutes to explore and choose a plant. Hand out pencils and clipboards. Demonstrate how to examine the plant closely, use the hand lens, and fill out the first part of the Plant Investigation worksheet. (5-7 min)

  • Have students write what they first notice about their plant. This only needs to be a few words.

  • Draw the plant. Remind students that scientific drawings focus on the details and don’t require artistic ability. Labels can help point out relevant structures.

  • Students should label one or two structures they notice on their plant. Have them try to figure out how the structure might help the plant survive (like get water, keep in water, resist herbivore,; or make seeds).

4) Bring the students back. Tell students their next task is to pretend they are detectives solving the mystery about how plants survive without a lot of water. Their job is to interview their plant. Explain that before interviews, detectives research their subject and plan out good questions to ask to help solve the mystery. Demonstrate how to ask good questions that can be addressed through direct observation. Show a poster of examples and sentence stems to help students formulate scientific questions. Release them to return to their plants. Circulate, listen to interviews, and support students who are having trouble. Listen for patterns in the students’ observations. (5-7 min)

Some scientific questions students could ask:

  • Descriptive questions that will help describe physical features of the plant/organism, such as color, size, shape, texture, etc.

    • How does the red color help the plant?

    • What color is its flower?

  • Counting and measurement questions for details such as height (think quantitative, i.e. this plant is around 5 feet tall), amount of pine needles per bundle, tree trunk diameter, etc.

    • How many petals does the flower have?

    • How tall is this plant?

  • Action/Functionality questions about the organism, like its movement and relationship to its surroundings   

    • What eats this plant?

    • Is the plant flexible or rigid?

  • Time questions like about how the plant changes over time

    • What would this plant look like in a different season?

    • How long did it take for this plant to grow?

Some questions to redirect:

  • Thinking or Feeling questions should be discouraged as these are questions with answers that can only be inferred or assumed rather than observed. 

  • Why questions take longer to answer and can be rephrased as “How…?” “What…?” or “What happens if…?” questions. For example, “Why is this plant growing in the shade?” vs. “What would happen if I were to move this plant into the sun?”

4) Invite a few students to share their questions and observations with the group. Ask students to include structures they observed and what functions those structures seem to accomplish that help the plant survive. Point out patterns in student responses. Explain that scientists look at structures and functions and ask questions to investigate the natural world.

Where should I live?

Objectives: Students will be able to:a. Name three plant structures that help a plant survive in the riparian environment.

Essential Question: Do plants in the riparian area have special structures to survive? How are those structures different from structures that serve the same function in the desert area?

Materials: plant ID sheets; hydrometers; measuring tape; temperature gauges

1) Invite students to look around and describe the surrounding plants. If students already attended the desert stations, encourage them to describe similarities and differences between plant structures in the two areas. Have students speculate with a partner about why the plants may be different. Show students a cocklebur plant you collected before the students arrived (with roots). Review the parts of the plant and compare to plants they saw in the desert environment. Some things to point out are shallow roots, large and soft leaves, no defenses, large seeds. Mention how it was also very easy to pull out of the sand. Ask if students think it would survive well in the desert. Pay attention to the colors of the roots versus green parts.

2) Tell students they are in a special part of the desert called the “riparian zone”. Point out the creek. Tell students the creek is why the riparian zone is so different. There is plenty of water, but the riparian zone has its own challenges for plants, just like the drier part of the desert. Have students guess what some of those challenges might be and write them on the whiteboard (floods, soil too wet, animals, too crowded with other plants, etc.).

3) Tell the students they will hike in the creek bed (if dry enough) or along the banks (if too flooded) to explore the plants living in the riparian zone to discover if they have structures that can help them survive riparian challenges. Show the students how the temperature and moisture gauges work.

4) Stop at several plants, discuss each plant’s size, shape, and leaf shape; use the plant ID sheets to name the plant. Test the soil moisture and temperature around the plant. Search for signs of flooding or signs that animals may be present. Bend some branches to discover if they bounce back. Examine roots in the bank. Record structures on the whiteboard that function to help plants overcome riparian challenges.

5) Conclude by asking if students would expect to find similar patterns in other local riparian areas.

Seeds travel

Objectives: Students will be able to:
a. Understand the function of seeds
b. Describe structures that help seeds travel

Essential Question: What types of structures help seeds travel in the desert?

STEM Design Challenge: Students will use the engineering design process to build a seed dispersal mechanism.

Materials: pictures of seeds; examples of seeds (i/e cottonwood, cocklebur); Engineering Design poster; whiteboards and dry erase marker (one per team/instructor); seed models (i.e. paperclips)- one per every 2-3 students; materials to make the seed dispersal structures (tape, string, pipe cleaners, rubber bands, Velcro, small pieces of paper); bucket; extra water.

Procedure:
1) Introduce seeds by having student do a pair-share about what they know about seeds. Ask students if seeds are important. Discuss what seeds do and why humans and other animals depend on plants and seeds to survive.

2) Discuss how and why seeds travel. Invite students to think back to their second-grade field trip and share what they remember. Seeds disperse using different mechanisms (wind, water, animals). Sometimes their structures provide clues about which mechanism a seed uses. List mechanisms on a whiteboard. Allow students to observe examples of each seed type (both pictures and actual seeds if available) and discuss student observations. Look for patterns in seed structures which help seeds travel.

3) Introduce the seed dispersal design challenge. Describe the steps in the engineering design process. Explain how engineers first define the problem, next brainstorm solutions, then make a plan, create and test the plan, and finally modify and improve the design. Today, their problem is that the majestic paper clip tree needs to spread out and make more paper clip trees throughout the canyon. It has seeds that look suspiciously like paper clips which fall straight down to the ground (demonstrate). Explain their challenge will be to construct a seed dispersal structure to move the seed as far as possible via either wind, animals, or water. Point out that we don’t have enough time to experiment with internal hitchhiking, so choose one of the other three for their designs.

4) Break students into teams of 2-3. Tell students that before they are given materials, they must discuss and develop a plan and draw a simple diagram of their seed design on a whiteboard (including a list of materials). Demonstrate how to draw the plan. After students show their design to the instructor, they will receive their materials.

5) Have students test their designs, and discuss limitations of their designs. Allow time for students to share their designs. Discuss if students had options of other materials, would they use the same ones?

6) Cleanup the station by having students take apart their designs and put reusable pieces back. Spend the last minute having students look for any trash from the area and stress the importance of cleaning up micro-trash.

Adaptation Art 
(Project WILD, 1992, 114-115) 

Objectives: Students will be able to: 
a. Name three adaptations of a plant living in either a desert or a riparian environment. 

Essential Question: Could we design plant structures to increase plant survival?  

Materials: 11x17 sheets of paper; markers, masking tape (to hang drawings), decision spinner 

Procedure:  
1) Briefly review some of the desert and riparian plant adaptations that students learned about on the field trip. As part of the discussion, review the parts of the plant and characteristics of riparian and desert environments. (5 min) 

2) Explain that students will be creating and drawing imaginary plants with imaginary adaptations. Remind students that each of the four main plant parts (roots, stems, leaves, flowers) must have an adaptation to help this plant survive in its environment long enough to attract a pollinator and reproduce. As a class, create a plant as an example. Think of the wackiest adaptations possible (such as umbrella-shaped leaves for shade). (5-7 min) 

3) Pass out sheets of paper and some markers to share. Students may work alone or in pairs. Students should to first decide which environment the plant is going to live in (desert or riparian) and write it in the corner. If students cannot decide, let them use the spinner. Encourage students to be as creative as possible as they design their own adaptations for their plants. Ask students to label their drawing with the plant’s chosen name. As they work, ask students how each crazy adaptation will help their plant to live long enough to reproduce. (10-15 min) 

4) Allow students to do a gallery walk to see each other’s creations. If time, invite a few students to stand in front of the class, show their drawing, and explain how each of their plant’s adaptations will help it survive and reproduce in their chosen area. If teachers approve, display drawings on the board. (5 min) 

Brady, I. (1998). The redrock canyon explorer. Talent, OR: Nature Works.

Braus, J. (Ed.). (1989). Discovering deserts. Ranger Rick’s NatureScope. Washington, DC: National Wildlife Federation.

Caduto, M. & Bruchac, J. (1994). Keepers of life: Discovering plants through native american stories and earth activities for children. Golden, CO: Fulcrum Publishing.

Cornell, J. B. (1979). Sharing nature with children. Nevada City, CA: Ananda Publications.

Fagan, D. (1998). Canyon country wildflowers: A field guide to common wildflowers, shrubs, and trees. Helena and Billings, MT: Falcon Publishing.

Hauth, K. B. (1996). Night life of the yucca: The story of a flower and a moth. Illus. by K. Sather. Boulder, CO: Harbinger House.

Nelson, R. A. (1976). The plants of Zion National Park. Springdale, UT: Zion Natural History Association.

Project WILD: K-12 activity guide. (2nd ed). (1992). Bethesda, MD: Council for Environmental Education.

Project WILD Colorado, n.d. Riparian Habitat. Poster. Denver, CO: Colorado Division of Wildlife.

Tweit, S. J. (1992). The great southwest nature factbook. Bothell, WA: Alaska Northwest Books.

Williams, D. (2000). A naturalist’s guide to canyon country. Helena, MT: Falcon Publishing.

 

Materials

Tags: structure function riparian plant adaptations desert plant adaptations leaves roots stems seeds

Last updated: November 16, 2022