Ch 26 Algae and Plants

primary endosymbiosis

when a eukaryotic cell engulfs a
prokaryotic cell, leading to a symbiotic relationship.
Incorporation of a cyanobacterium into a primitive
eukaryotic cell, which eventually evolved into the
chloroplasts found in plants and algae.

secondary endosymbiosis

a process in which a
eukaryotic cell engulfs another eukaryotic cell that has
already undergone primary endosymbiosis. This typically
involves a eukaryotic host cell ingesting a photosynthetic
eukaryote, such as a green or red alga, which itself
contains chloroplasts derived from primary
endosymbiosis.

glaucophytes

a group of freshwater algae (a protist)
• Unique Chloroplasts that retain a peptidoglycan layer, similar to
those found in cyanobacteria.
• They typically have a simple unicellular structure, although some can
form colonies.
• Chlorophyll a pigment

red algae

Most are multicellular.
Red color results from the accessory
photosynthetic pigment phycoerythrin.
The chloroplasts also have chlorophyll a and
other accessory pigments

holdfast

Most red algae are marine; a few live in
freshwater; most grow attached to a
substrate by a…

green algae

have chlorophylls a and b and
store photosynthetic products as starch in
chloroplasts

chlorophytes

Largest group of green
algae; most are aquatic.
Unicellular and multicellular species; great
diversity of shapes and body forms

volvox

a freshwater unicellular alga, forms
large colonies with some cells specialized
for reproduction

ulva

similar to volvox, but multicellular

streptophytes

All green algae other than
chlorophytes, plus land plants

coleochaetophytes and stoneworts

closest relatives of land plants; they are multicellular

embryophytes

A synapomorphy of land plants is an embryo
protected by tissues of the parent plant.
They are also called…

vascular plants

Vascular systems
transport materials throughout the plant
body (7 clades)

tracheophytes, tracheids

another name for vascular plants is _____ they have fluid-conducting cells called ________

Non-vascular plants

The other 3 clades
lack tracheids (liverworts, mosses, and
hornworts)

things plants on land need

Water transport mechanisms
• Physical support
• Mechanisms to distribute gametes and
progeny

cuticle

adaptation of land plants: waxy coating that retards water
loss (most important and earliest)

Stomata

adaptation of land plants: openings in stems and leaves;
regulate gas exchange and water loss

gametangia

adaptation of land plants: organs enclosing gametes

soil structure

Organic material from dead plants
contributes to…

alternation of generations

1.Multicellular diploid state and a
multicellular haploid state
2. Gametes produced by mitosis. Spores
produced by meiosis that developed into
haploid organism.

Alternation of Generations on Land Plants

1. gametophyte produces haploid gametes by mitosis

2. gametes fuse to form zygote

3. zygote develops into siploid sporophyte

4. sporophyte produces haploid spores by meiosis

5. spores germinate anddivide to form haploid gametophyte

sporophyte

Multicellular diploid plant is the…

sporangia

Cells in ____ undergo meiosis to
produce haploid, unicellular spores

gametophyte

Spores develop into a multicellular
haploid plant—the …

haploid, mitosis

gametophytes produce___gametes by _____

fertilization

fusion of gametes

diploid zygote

fertilization results in a…

multicellular sporophyte

zygote develops into the

diploid, fusion of gametes

The sporophyte is the _____phase of
the plant life cycle that develops from the_____

haploid, spores from sporophyte

the gametophyte is the ____ phase of the plan life cycle that develops from the___

reduction

There is a trend toward ______ of the
gametophyte generation in plant evolution

larger, more self-sufficient

In nonvascular plants the gametophyte is
_____, longer-lived, and _______
than the sporophyte

liverworts, mosses, hornworts

Nonvascular Plants

short

NONVASCULAR PLANTS: No vascular transport system—plants are…

diffusion

NONVASCULAR PLANTS: Water transport is via__

thin or no

non vascular plants have _____or_____ cuticle and most live in moist habitats

true leaves, stems, and roots

nonvascular plants lack…

mutualistic associations with fungi

Some nonvascular plants can live on bare
rock and other marginal habitats because
of_______

sporophyte, gameto

___phyte is always nutritionally dependent
on the ___ophyte and is permanently
attached

sporangium

sporophyte produces spores in a _____

gametophyte

___ophyte is the photosynthetic form

water

nonvasculuar reproductive cycle needs_____ to bring sperm to egg

vascular plants

Key synapomorphy is a vascular system.
Ability to transport water and food
throughout the plant body allowed them to
spread to new environments and diversify
rapidly.

xylem

conducts water and minerals from soil
up to the rest of the plant (1 way)

phloem

conducts products of photosynthesis
throughout the plant (2 way)

lignin

Some xylem cell walls have ____, which
provides support

more spores, complex

A branching sporophyte can produce ____ and develop in ____ ways.

The sporophyte is the familiar,
photosynthetic form; it is nutritionally
independent from the gametophyte

In vascular plants:

vascular

Vascular or nonvascular: sporophyte is nutritionally independent from gametophyte

nonvascular

vascular or non vascular: sporophyte is nutritionally dependent on gametophyte

Rhyniophytes (Silurian)

Earliest vascular plants (now extinct)
• Simple vascular system
• Dichotomous branching
• Lacked leaves and roots
• Anchored by rhizomes (horizontal
stem) and rhizoids (water-
absorbing filaments)

lycophytes

Club mosses, spike
mosses, quillworts; 1,200 species.
• Stems and true roots with
dichotomous branching.
• Simple leaflike structures
(microphylls) arranged spirally.
• Some have sporangia arranged in
clusters called strobili.

monilophytes

ferns and horsetails are…

Horsetails

True roots; sporangia on short
stalks called sporangiophores.
• Reduced leaves grow in whorls.
• Silica in cell walls—“scouring
rushes.”

ferns

Most are terrestrial, a few are aquatic.
• Large leaves with branching vascular
strands, some fern leaves climb and may
grow up to 30 m

homosporous

The most ancient vascular plants were
______—having one type of spore

megaspores and microspores

Heterosporous plants produce 2 spore
types:

megaspores, megagametophytes

______develop into female
gametophytes—_____gametophytes,
which produce only eggs

microspores, microgametophytes

______ develop into male
gametophytes—___gametophytes,
which produce only sperm