Plant Diversity

Front 1

Monophyletic

Back 1

Land plants are monophyletic, all descend from a single common ancestor.

Front 2

Synapomorphy

Back 2

Development from an embryo
protected by tissues of the parent plant (embryophytes)

Front 3

First land plants

Back 3

Plants first appeared on land between 400–500 million years ago.
Adaptations were needed to survive in a dry environment.
Large plants needed a way to transport water to all parts of the plant.
Land plants also needed support and methods to disperse gametes.

Front 4

Clades of land plants

Back 4

Vascular plants (seven)
Nonvascular plants (three)

Front 5

Vascular plants

Back 5

All have conducting cells called tracheids. The seven groups of vascular plants constitute a clade.

Front 6

Tracheids

Back 6

Conducting cells in vascular plants.

Front 7

Nonvascular plants

Back 7

The remaining three clades—
liverworts, hornworts, and
mosses.
These groups do not form a
clade.

Front 8

Alternation of Generations

Back 8

All land plants have a life cycle with alternation of generations.
Includes multicellular diploid
(sporophyte) and multicellular haploid (gametophyte) individuals.

Meiosis-spore-mitosis-multicellular gametophyte-mitosis-gametes-fertilization-zygote-mitosis-multicellular sporophyte-meiosis

Front 9

Sporophyte

Back 9

Gametes fuse and fertilize, make spores that grow up to be gametophytes

Front 10

Gametophyte

Back 10

Makes gametes by mitosis

Front 11

Characteristics of nonvascular plants

Back 11

Today’s nonvascular plants are
thought to be similar to the first land plants.
They grow in moist environments in dense mats.
They are small, there is no
system to conduct water from soil to plant body parts.

Front 12

Differences between sporophyte and gametophyte stages in nonvascular plants.

Back 12

In nonvascular plants, the
gametophyte generation is
photosynthetic.

The sporophyte may or may
not be photosynthetic, but is
always nutritionally dependent on the gametophyte, and is
permanently attached.

Front 13

Reproduction in Nonvascular Plants

Back 13

e.g. Bryophytes (moss)
The haploid gametophyte produces gametes in
specialized sex organs.

Front 14

Archegonium

Back 14

Female: archegonium;
produces one egg.

Front 15

Antheridium

Back 15

Male: antheridium;
produces many sperm
with two flagella each.

Front 16

Sori

Back 16

clusters of sporangia

Front 17

Characteristics of Vascular Plants

Back 17

The vascular system consists of
tissue specialized for the transport of materials.
Xylem conducts water and minerals from soil up to aerial parts of plant.
Some cells have lignin provides support.
Phloem conducts products of
photosynthesis through plant.

Front 18

Xylem

Back 18

Conducts water and minerals from soil up to aerial parts of plant.

Front 19

Lignin

Back 19

Hardens and strengthens a cell to provide support

Front 20

Phloem

Back 20

Conducts products of
photosynthesis through plant

Front 21

Reproductive characteristics of Non seeded Vascular Plants

Back 21

e.g. ferns In the seedless vascular plants, the large sporophyte is independent of the small, shortlived gametophyte.
The single-celled spore is a resting stage.
Must have water for part of the life cycle—for the flagellated, swimming sperm.

Front 22

Reproduction in a Non-seeded
Vascular Plant: The Fern

Back 22

Spore mother cells in sporangia form haploid spores by meiosis.
Spores can be blown by wind and develop into gametophyte far from parent plant.

Haploid SPORES form on the Sporophyte (2n) of a Fern

Front 23

Seeded plants fall into two
groups:

Back 23

Gymnosperms: pines and cycads
Angiosperms: flowering plants

Front 24

Reproduction Characteristics of Seeded Vascular Plants

Back 24

Gametophyte generation is reduced even further than it is in ferns.
Haploid gametophyte develops partly or entirely while attached to the sporophyte.
Only the earliest gymnosperms had swimming sperm.
Without swimming sperm, seed plants were able to be independent of water for sexual
reproduction; an advantage for existence on land.

Front 25

Reproduction in the Seeded Plants

Back 25

Pollen: the male gametophyte
Pollination: when a pollen grain lands near a female gametophyte.
A pollen tube is produced that digests its way through the sporophyte tissue to the female gametophyte.
Sperm are released from the tube, and fertilization results in a diploid zygote.
Diploid zygote divides to produce an embryonic sporophyte.
Growth is then suspended, the embryo enters a dormant stage, with the end product being a multicellular seed.

Front 26

Pollen

Back 26

The male gametophyte

Front 27

Pollination

Back 27

When a pollen grain lands near a female gametophyte

Front 28

Pollen tube

Back 28

Produced to digests its way through the sporophyte tissue to the female gametophyte. Sperm are released from the tube, and fertilization results in a diploid zygote.

Front 29

Seeds

Back 29

Well-protected resting stages.
May remain viable for many
years, germinating when conditions are favorable.
Seed coat protects from
drying out as well as predators.
Many seeds have adaptations for dispersal.

Front 30

Gymnosperm

Back 30

“naked-seeded”—the ovules and
seeds are not protected by ovary or fruit tissue.
Exant gymnosperms are probably a clade.
e.g. pine tree

Front 31

Synapomorphies (shared traits) of
the Angiosperms:

Back 31

1. Double fertilization
2. Triploid endosperm
3. Ovules and seeds enclosed in a carpel
4. Flowers
5. Fruits
6. Xylem with vessel elements and fibers
7. Phloem with companion cells

Front 32

Double fertilization

Back 32

Microgametophyte has two male gametes.
Nucleus of one combines with egg.
The other nucleus combines with two haploid nuclei of female gametophyte to form a triploid nucleus—becomes the endosperm.
Endosperm nourishes developing sporophyte.

Front 33

Angiosperm

Back 33

“enclosed seed”—the ovules and seeds are enclosed in a modified leaf called a carpel (aka pistil)
Vascular Plants: Angiosperms
Carpels provide protection
The flower is the reproductive organ

Front 34

Animal-pollination

Back 34

Most angiosperms are animal-pollinated—by insects, birds, and
bats.
Many flowers entice pollinators with nectar and pollen.
Plants and their pollinators have coevolved; some relationships are very specific.

Front 35

Angiosperms clades

Back 35

Monocots e.g. corn
Eudicots e.g. beans

Front 36

Differences between monocots and eudicots

Back 36

Monocots have one cotyledon, eudicots have 2. Monocots veins in leaves are parallel, eudicots are net-like. Monocots flowering parts are in multiples of 3, eudicots are in multiples of 5. Monocots arrangement of primary vascular bundles in the stem are scattered, eudicots are in a ring.