
Overview of Land Plants:
○ Bryophytes  “non-_____________________________”; mosses; flagellated sperm; gametophyte
= dominant phase and sporophyte is dependent on the gametophyte
○
Pteridophytes

“___________________________”; but __________________________; ferns; flagellated sperm; __________________________ = dominant phase; free-living gametophyte
○
Gymnosperms

“____________________________” with ________________ (so nonflagellated sperm); conifers; no _____________________________________; sporophyte = dominant phase; gametophyte retained within the sporophyte (gametophyte = non-photosynthetic)
○
Angiosperms

“__________________________” with _____________________ (so nonflagellated sperm) and _____________________________; flowering plants; sporophyte = dominant phase; gametophyte retained within the sporophyte (gametophyte = non-photosynthetic)
Concept 29.1 Land plants evolved from green algae.

Researchers have identified a lineage of green algae called ___________________________
( ___________________________________ ) as the closest relatives of land plants.

Many key traits of land plants also appear in some algae.
Multicellular, ___________________________, ___________________________________.
Cell walls made of _______________________________.
Chloroplasts with chlorophyll _____ and _______ .

The charophytes (charophyceans) are the only algae that share the following four distinctive traits with land plants , strongly suggesting that they are the closest relatives of plants.
1.
Distinctive rings of cellulose-synthesizing complexes (synthesize the cell wall.)
2.
Peroxisome enzymes
3.
Flagellated sperm
4.
Formation of a ______________________________________ (cell plate) during division.
Four key traits distinguish land plants from algae (so only land plants have these traits):
1.
______________________________________________ (along with multicellular, dependent embryos)

in green algae, embryos are NOT retained within the parental tissue
29-1

2.
Sporangia that produce __________________________________
3.
Gametangia that produce ________________________
4.
________________________________________

NOTE: Some of these traits are not unique to plants; not every land plant exhibits all four traits.
Plant life cycles are characterized by alternation of generations, with multicellular, dependent embryos.

All land plants show alternation of generations in which two multicellular adult body forms alternate.
In alternation of generations:
One of the multicellular bodies is called the gametophyte and has ____________________ (___) cells .
Gametophytes produce ______________________ , __________ and ________________, by mitosis .
The fusion of egg and sperm during ________________________ forms a __________________
(____) _________________________ .
Mitotic division of the diploid zygote produces the other multicellular body, the __________________ .
__________________________ in a mature sporophyte produces haploid reproductive cells called
_______________________ . Mitotic division of a plant spore produces a _______________________
____________________________________________ .
○
A spore is a reproductive cell that can develop into a new organism without fusing with another cell.
(2n) Spores (n)
Microspore – male
Gametophyte (n)
Pollen – male
Megaspore - female
Embryo Sac - female
Mitosis Mitosis
Gametes (n)
Sperm – male
Egg - female
In plants, walled spores are produced by ______________________________.

Plant spores are haploid reproductive cells that grow into gametophytes by mitosis.

________________________ makes the walls of spores very tough and resistant to harsh environments.

Multicellular organs called ______________________ are found on the sporophyte and produce spores.
29-2

○
Within sporangia, diploid cells called sporocytes undergo __________ and generate haploid spores.

The outer tissues of the sporangium protect the developing spores until they are ready to be released into the air.
Plant gametophytes produce gametes within multicellular organs called ____________________________.

A female gametangium , called an _________________________________, produces a single _______ cell in a vase-shaped organ and the egg is retained within the base.

Male gametangia , called ______________________________, produce and release _______________ into the environment.
Land plants have diversified since their origin from algal ancestors.

Land plants can be informally grouped based on the presence or absence of an extensive system of
_______________________________ tissue , cells joined into tubes that transport ________________ and nutrients throughout the plant body.
○
Most plants have a complex vascular tissue system and are called vascular plants .
○
Plants that do not have an extensive transport system (liverworts, hornworts, and mosses) are described as __________________________________ plants (which are bryophytes).
Concept 29.2 BRYOPHYTES  no vascular tissue!
Mosses and other nonvascular plants have life cycles dominated by ______________________________.

The nonvascular plants (bryophytes) are represented by three phyla:
1.
Phylum __________________________— liverworts
2.
Phylum Anthocerophyta— _____________________________
3.
Phylum Bryophyta— ______________________________

In bryophytes, haploid gametophytes are the largest and most conspicuous phase of the life cycle.
( Gametophyte = Dominant Phase )
○
Sporophytes are _____________________ and are present ________________________________. o Bryophyte spores germinate in favorable habitats and grow into gametophytes by ______________.
 Lacking vascular tissue, most bryophytes are only _______________________________________ tall.

The thin structure of bryophytes makes it possible to distribute materials for short distances without specialized vascular tissue.
29-3


Although bryophyte sporophytes are green and photosynthetic when young, they cannot live
__________________________________ from their parental gametophyte.
○ The sporophyte generation remains ________________________________________________ , from which they absorb __________________, amino acids, ____________________, and water.
● Bryophytes have
________________________________ sperm .
Concept 29.3 PTERIDOPHYTES

seedless, vascular (ferns!)
Ferns and other seedless vascular plants were the first plants to grow tall.

Bryophytes were the prevalent vegetation for the first _________________________ years that terrestrial communities existed.
○
__________________________ plants dominate most landscapes today.

The sperm of ferns and all other pteridophytes are _______________________________ and swim through a film of water to reach eggs.

Unlike bryophytes, these plants had branched sporophytes that did not remain dependent on gametophytes for growth.

Three main traits characterize modern vascular plants:
1.
Life cycles with ________________________________________________,
2.
Transport in vascular tissue called _______________ and _____________________,
3.
Well-developed ________________ and _____________________, including spore-bearing leaves called _______________________________.
Vascular plants have life cycles with dominant sporophytes and a reduced gametophyte.

Among living vascular plants, the ________________________________ (diploid) generation is the larger and more complex plant.  remember diploid organisms are protected by many effects of mutation because there are TWO sets of chromosomes

The reduced size of the gametophytes is even more extreme in _________________ plants.
Vascular plants have two types of vascular tissue: xylem and phloem.

Xylem conducts most of the _____________________ and ___________________ up from the
________________; the cells are ________________________ at functional maturity. o The xylem of all vascular plants includes tracheids , _____________________________________
________________________________________________________________________________.
29-4

o The water-conducting cells in vascular plants are _____________________________, strengthened by the polymer ________________________ .

___________________________ is a living (cells are alive!) tissue in which _____________________
_____________________ cells are arranged into tubes that distribute sugars, amino acids, and other organic products; they generally transport from ________________________________________ of the plant (leaves) to the rest of the plant.

Lignified vascular tissue permitted vascular plants to grow tall.
Lignified vascular tissue (hard material in cell walls) allowed the evolution of roots.

Roots are organs that _________________________________________________________________
___________________________________________________________________________________.
○ Roots also anchor vascular plants, allowing the shoot system to grow taller.
○
So land plants (except for bryophytes) have true _______________ , ____________________ and
_______________________ because of the vascular tissue.
Leaves capture solar energy for photosynthesis.

Leaves are organs that increase the ________________________________________ of vascular plants to capture ____________________.
Vascular plants have sporophylls, modified leaves that bear sporangia.

Sporophylls vary greatly in structure. Sporophylls are leaves specialized for _____________________.

Most seedless vascular plants are _____________________________ , producing a single type of spore.

A heterosporous species produces ______________________________________________________.
○
Megasporangia produce __________________________ , which develop into _________________
________________________________ .
○ Microsporangia produce comparatively smaller _________________________________ , which develop into _______________________________________ .

All seed plants and a few seedless vascular plants are heterosporous.
Seedless vascular plants played an important role in the history of life on land.

The first forests gave rise to modern-day coal. o In the stagnant waters of the ________________________ period, dead plants did not fully decay.
29-5

o The organic material turned to thick layers of _________________. Marine sediments piled up on top, and over millions of years, __________________ and ______________________ converted the peat to ____________________.

Humans still burn ______________________________ tons of coal each year. o Coal, formed from plants that contributed to global cooling, now contributes to _________________
________________________ by returning ____________________________ to the atmosphere.
Other Important Notes :
Water conservation was an issue when plants came out of the water to colonize land, so they had the following structures to try to prevent dessication (drying out) and help adapt : o Waxy cuticles

prevent water loss o Stomata

pores on the surface of leaves that function in gas exchange; controlled by guard cells o Vascular Tissue

xylem and phloem for transport
Other adaptations for land existence in addition to vascular tissue were apical meristems , seeds , and flowers .
-
If leaves wilt because there isn’t enough water, the stomata close so there is a decrease in gas exchange and therefore there is a decrease in photosynthesis
-
The first land plants didn’t have to deal with animal predators
29-6