Reading Essentials for Biology Glencoe (794133), страница 57
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The sperm are produced in this structure. The archegonium (ar kih GOH nee um)is the female reproductive structure. Eggs are produced in thisstructure. Fertilization happens in the archegonium and beginsthe sporophyte generation.READING ESSENTIALSHighlight MainIdeas Underline the name ofeach nonvascular plant division in this section. Say thename aloud. Then highlightthe words or phrases thatdescribe that plant division.Sporophyte withsporangium (2n)Gametophyte (n)Chapter 22243NameDateClassSection22.1Nonvascular Plants, continuedAdaptations in BryophytaThere are several divisions of nonvascular plants. You will lookat the mosses, or bryophytes, first. Of all the nonvascular plants,people are most familiar with bryophytes.Mosses are small plants with leafy stems.
The leaves are usuallyone cell thick. Instead of roots, mosses have rhizoids, colorlessmulticellular structures, to help anchor the plant to the soil.Mosses usually grow in a thick ground covering of hundreds ofplants. Large areas of growing moss help prevent erosion.Mosses grow in a variety of habitats. They even grow in the arcticduring the brief growing season when enough moisture is present.Sphagnum, a well-known moss also known as peat moss, is usedas fuel. Dried peat moss absorbs large amounts of water, soflorists and gardeners use it to increase the water-holding abilityof soil.1.
What are the two classifications of liverworts?________________________________________________2. What kind of body dohornworts have?________________________________________________________________________244Chapter 22Another division of nonvascular plants is the liverworts, orhepaticophytes. Like mosses, liverworts grow as clumps or massesin moist environments. The division hepaticophyta derives its namefrom hepar, which refers to the liver. The shape of the liverwortgametophyte is thought to look like an animal’s liver. Liverwortsare found all over the world.There are two classifications of liverworts. One is called thallose; the other is called leafy. The body of a thallose liverwort iscalled a thallus.
It is broad and resembles a fleshy, lobed leaf.Thallose liverworts are usually found growing on damp soil.Leafy liverworts are common in tropical jungles and places thatare often blanketed by fog. They look less like a liver than thethallose variety.
The stems have three rows of flat, thin leaves.Liverworts have rhizoids made up of one long cell to help anchorthe plant to the soil.Adaptations in AnthocerophytaAnthocerophytes are known as hornworts. They are similar toliverworts in several ways. Like some liverworts, hornworts have athallose body. The sporophyte of a hornwort resembles the hornof an animal, which is why they are called “hornworts.”Hornworts have one to several chloroplasts in each cell of thesporophyte, depending on the species. Unlike other nonvascularplants, the sporophyte, not the gametophyte, produces most of thefood used by both generations.READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Adaptations in HepaticophytaNameDateClassSection22.1Nonvascular Plants, continuedOrigins of Nonvascular PlantsFossil and genetic evidence suggests that liverworts were thefirst land plants.
Fossils from the Paleozoic Era, more than 440million years ago, have been identified as nonvascular plants.However, scientists hypothesize that nonvascular plants weregrowing even earlier than that. Both nonvascular and vascularplants may share a common ancestor. That ancestor probablyhad alternating sporophyte and gametophyte generations, cellulose in the cell walls, and chlorophyll for photosynthesis.3.
What do scientistshypothesize were thefirst land plants?________________________________________________________________________◗ After You ReadMini Glossaryantheridium (an thuh RIH dee um): male reproductive structure in which sperm developarchegonium (ar kih GOH nee um): female reproductive structure in which eggs develop1. Read the terms and definitions in the Mini Glossary above. On the lines below, tell how thetwo key terms are related.____________________________________________________________________________________Copyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.________________________________________________________________________________________________________________________________________________________________________2.
Use the table to give an example of each division of nonvascular plants. Then list the sharedcharacteristics of these plants.Nonvascular PlantsDivisionExampleShared CharacteristicsBryophytaHepaticophytaAnthocerophytaVisit the Glencoe Science Web site at science.glencoe.com to findyour biology book and learn more about nonvascular plants.READING ESSENTIALSChapter 22245NameDateClassSection22.2 Non-Seed Vascular PlantsSC.F.1.4.2 The student knows that body structures are uniquely designed and adapted for their function. Also coversSC.D.1.4.4, SC.F.2.4.1◗ Before You ReadHave you ever gone camping or visited another part of the world where plumbing was not available?What did you miss most about not having plumbing? Write your thoughts on the lines below.
Themain purposes of plumbing are to bring water and carry away wastes. Some plants have plumbing.This plant plumbing—called vascular tissues—distributes water and other dissolved substancesthroughout a plant.______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________◗ Read to LearnCreate a Quiz After youhave read this section, createa quiz based on what youhave learned.
After you havecompleted writing the quizquestions, be sure to answerthem.In this section you will learn about three divisions of non-seedvascular plants: Lycophyta, Arthrophyta, and Pterophyta. Themain difference between vascular and nonvascular plants is thatvascular plants have vascular tissue. Vascular tissue is made oftubelike, long cells through which water and nutrients travel.This makes it possible for vascular plants to live in a varietyof habitats.How do vascular plants exhibit alternationof generations?Like all plants, vascular plants have an alternation of generations.Unlike nonvascular plants, however, the dominant generation invascular plants is the sporophyte.
The sporophyte is larger in sizethan the gametophyte. The sporophyte does not depend on thegametophyte for water or nutrients.An important advance in non-seed vascular plants was theadaptation of leaves to protect the developing reproductive cells.In some of the plants, leaves that bear spores form a compactcluster called a strobilus (stroh BIH lus). The spores are releasedfrom the strobilus and can grow to form gametophytes.The illustration on page 247 shows a fern gametophyte called aprothallus (proh THA lus). Gametophytes are relatively small.They live in or on the soil.246Chapter 22READING ESSENTIALSCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.What is a non-seed vascular plant?NameDateClassSection22.2Non-Seed Vascular Plants, continuedReproductive structures—the archegonium andthe antheridium—develop on the gametophyte.Sperm are released from the antheridia.
Spermneed a continuous film of water to reach and fertilize the eggs in the archegonia. The zygote cangrow into a large, dominant sporophyte.EggArchegoniumAdaptations in LycophytaCopyright © by Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Fossil evidence shows that ancient lycophyteswere the size of trees and part of the early forestcommunity. Modern lycophytes are much smallerand are called club mosses or spike mosses. Theleafy stems look like moss gametophytes, andtheir reproductive structures are club or spikeshaped. However, unlike mosses, the sporophytegeneration of lycophytes is dominant.
The sporophyte has roots, stems, and small leaflike structures. A single vein of vascular tissue runs througheach leaflike structure. The stems of lycophytesmay be sticking up or along the ground and haveroots growing from the base of the stem.ProthallusSpermRhizoidsAntheridiumAdaptations in ArthrophytaLike the lycophytes, arthrophytes (horsetails) were once treesized members of the early forest community.
Today they grow toabout 1 m tall. The name horsetail refers to the bushy appearanceof some species. There are only about 15 species of arthrophytesin existence. Sometimes they are called scouring rushes becausethey contain silica, an abrasive material. In the past, people usedhorsetails to scrub pots and pans.Most horsetails grow in damp soil in shallow ponds, in marshes,and on stream banks. The ribbed and hollow stem is not likeother vascular plants. It appears jointed, and at each joint there isa circle of tiny scalelike leaves.Arthrophyte spores are produced in strobili. After the sporesare released, they grow into gametophytes with antheridiaand archegonia.1.
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