Ch27: Seedless plants

all land plants evolved from a common ancestor, known as

green algae

complex multicellular eukaryotes with cellulose cell walls, chlorophylls a and b in plastics, starch as a storage product, and may have cells with two anterior flagella

plants

unlike green algae, all land plants develop from…

multicellular embryos enclosed in maternal tissues

a _________ __________ prevents plant tissues from drying out

waxy cuticle

_________ allows gas exchange through the cuticle

stomata

plant sex organs have a layer of ____________ ________ that protects the gametes

nonreproductive cells

plant life cycles have a haploid __________ stage and a diploid ______________ stage

gametophyte, sporophyte

antheridia

male gametangia that form sperm cells

archegonia

female gametangia that bears a single cell

red algae, green algae, and land plants are collectively classified as _____________

archaeplastids

plants consist of four major groups:

bryophytes (nonvascular plants), seedless vascular plants, gymnosperms, angiosperms (flowering plants)

_______ and ____________ are small nonvascular plants that lack a specialized vascular system to transport nutrients, water, and essential minerals, so they rely on __________ and __________ to obtain needed materials which restricts their size

mosses & byrophytes, diffusion & osmosis

vascular plants (seedless vascular plants, gymnosperms, and flowering plants) have two types of vascular tissues:

xylem & phloem

xylem

conducts water and dissolved minerals

phloem

conducts dissolved organic molecules, such as sugar

a key step in evolution of vascular plants was the ability to produce _______

lignin (hard outer shell)

seedless vascular plants reproduce and disperse primarily via ______

spores

____________ reproduce by forming unprotected seeds on a stem or in a cone

gymnosperms

angiosperms reproduce by….

forming seeds enclosed within a fruit

the only living nonvascular plants

byrophytes

bryophytes have three phyla:

byrophyta (mosses), hepatophyta (liverworts), anthocerophyta (hornworts)

live in dense colonies/beds, have tiny hairlike absorptive structures, play an important role in forming soil

mosses (phylum bryophyta)

body form is a thallus, not differentiated into leaves stems or roots, hairlike rhizoids anchor plants to soil, lack stomata

liverworts (phylum hepatophyta)

liverwort life cycle is basically the same as that of _______.

• sexual reproduction involves production of __________ on the haploid ________

• some liverworts produce asexually by forming tiny balls of tissue called _________

mosses

• gametangia

• gametophyte

• gemmae’s

superficially resemble liverworts, but cell structure resembles certain algal cells more than plant cells

hornworts

In hornworts, archegonia and antheridia are embedded in the _______________ ________ rather than on archegoniophores and antheridiophores

• a single gametophyte often produces multiple _______; meiosis occurs, forming spores within each __________

• sporophytes have ________ growth

gametophyte thallus

• sporophytes, sporangium

• intermediate

Botanists use ________ to study plant genetics, growth and development, ecology, hormones, and photoperiodism

bryophytes

Physcomitrella

moss; important for studying plant evolution, features comparable to algae and flowering plants

specialized vascular tissues allow vascular plants to….., water, minerals, & sugar are transported to all parts of the plant

grow to larger sizes

_________ _________ plants have true stems with vascular tissues - most with true roots or leaves

• _______ are the main organs of photosynthesis (microphylls and megaphylls)

seedless vascular

• leaves

The two main clades of seedless vascular plants:

club mosses & ferns

small, evergreen plants with true roots; rhizomes and erect aerial stems; and microphylls

• sporangia are borne on _______________ _______

• common in

club mosses (phylum lycopodiophyta)

• reproductive leaves

• temperate woodlands

most terrestrial plants with a dominant sporophyte generation and true roots

• sporophyte has a horizontal underground stem (________), that bears complex, compound leaves (______) that emerge from the ground tightly coiled (______________)

ferns (phylum pteridophyta)

• rhizome

• fronds

• fiddlebond

The fern life cycle alternates between the ______________ & the ________________

• spore production occurs in _____ on fronds of the ___________

• flagellate sperm cells swim from an ____________ to the neck of an ____________ through a thin film of water on the ground underneath the ___________

dominant diploid sporophyte & haploid gametophyte

• sori, sporophyte

• antheridium, archegonium, prothallus

Relatively simple ferns with vascularized stems, but lack true roots and leaves

• whenever the stem forks, it divides into _________

• tiny, round sporangia are borne on _______, _________

• haploid prothalli grow ____________, are nonphotosynthetic, and have a _________ relationship with mycorrhizal fungi

whisk ferns

• two equal halves

• erect, aerial stems

• underground

• symbiotic

ferns with true roots; hollow, jointed stems impregnated with silica; and small leaves fused in whorls at each node

• each reproductive branch bears a terminal conelike strobilus that contains _________

• the life cycle is similar to that of

horsetails

• sporangia

• ferns

Homospory

production of only one type of spore as a result of meiosis

Heterospory

production of two types of spores

Each strobilus bears two kinds of sporangia:

microsporangia & megasporangia

microsporangia produce ______________, which undergo meiosis to form microscopic, haploid _______________, and then develop into _______________

microsporocytes, microspores, male gametophytes

megasporangia produce ______________, which undergo meiosis to form haploid ______________, and then develop into ________________

megasporocytes, megaspores, female gametophytes

Botanists use _________ _____________ _______ as models to study plant physiology, growth, and development

seedless vascular plants

Seedless vascular plants are useful in studying how apical meristems give rise to ________ ________

plant tissues

Ferns are interesting subjects for genetic studies because they are ___________, but express genes like a ________ _______

polyploids, diploid plant

Evolution of Seedless vascular plants

• the oldest known megafossils of early vascular plants are from ________, but microscopic spores of early vascular plants appear in the fossil record earlier

• botanists assign the oldest vascular plants (rhynia, aglaophyton) to ________ _______________

• the oldest megafossils of fernlike trees are dated

• 420 mya

• rhylum rhyniophyta

• 380 mya