The Plant Kingdom

Bio 20 Unit 4From “The Plant Kingdom Notes”Adapted from notes by T. Greenshields (2004) Revised by S. Pipke-Painchaud (2005)

Plant Characteristics

all plants are photosynthetic since they contain chlorophyll

plants are multicellular organismsplants are divided into 2 main

categories, or phyla Bryophytes Vascular Plants

Classification of Plants

true mosses hornw orts liverw orts

Bryophytes

angiosperms gym nosperms

seeds

club m osses horsetails ferns

spores

Vascular P lants

Land P lants

Phylum Bryophyta - 24 000 species

Bryophytes have no vascular tissue to conduct fluids throughout the body. This restricts them to moist environments and a small size. *

*

- bryophytes continued...

Bryophytes do not have true roots, stems or leaves

instead of roots, the plant is anchored by thread-like rhizoids

Many bryophytes become dormant in dry conditions

Bryophyte Reproduction

Need moisture for sexual reproduction to occur since flagellated sperm must swim to the egg

life cycle includes alternation of generations between: haploid (n) phase (gametophyte) diploid (2n) phase (sporophyte)

The sporophyte capsule forms haploid spores. These spores are released and grow into gametophyte plants with a half set of genes

the gametophytes then produce either sperm or eggs. The sperm from male gametophytes swim to eggs in female gametophytes. The egg is fertilized and grows into a 2n sporophyte.

Classes of Bryophytes

3 classes: true mosses, liverworts, and hornworts 1. Mosses are the largest class and include

sphagnum moss, some of which formed after the Pleistocene Ice Age and has grown ever since. In Ireland, sphagnum moss from bogs is drained and peat is burned in electric generators. Ireland relies heavily on coal (non-renewable

resource) - peat is also a limited supply.

Bog People

• anything that dies in a bog is well preserved• Peat contains sphagnum associated plants

• it contains pollen grains from surrounding plants which provides a log of the vegetative changes over the years

• Animals and humans are well preserved

Let’s Meet the Bog People Website

Tollund Man

2. Liverworts and, *

3. Hornworts also grow in moist areas and often have “lobed” bodies *

Vascular Plants

Phylum Tracheophyta - 211 000 species most vascular plants have adapted to

conserve water so that they can survive on land

have conducting tissue to transport water and dissolved nutrients (xylem and phloem)

true leaves and stems and well-developed root systems

Vascular plants continued ...

adapted to conserve water (waxy cuticle) reproduce by spores or seeds and do not

require water for sexual reproduction life cycle also exhibits alternation of

generations, though usually contained within one plant

2 groups: seed-producing and spore-producing

Spore - producing

1. Club mosses (Division Lycophyta) are not mosses but evergreen plants

that are usually under 40 cm tall * many species produce spores in club-

shaped cones at the tip of short-upright stems *

2. Horsetails (Division Sphenophyta) have hollow, jointed stems growing from

horizontal underground stems. They have small, scale-like leaves (at each joint) and contain silica and so are harsh to the touch. People used them to scour pans. (hence the common name scouring rushes)

* The Giant Horsetails Intro to Sphenophyta

3. Ferns like the club mosses and horsetails, these

reproduce by spores, which can be seen as small brown spots (sorus/ sporangia) on the undersides of their leaves *

lives in the shade with underground stems and roots. Everything above ground is leaves.

Life cycle includes a tiny gametophyte stage and a large sporophyte stage

Image from: Digital Saskatchewn & Kenton Letkeman © 2005

Ferns continued ….

after spores on the underside of the leaf have developed they disperse *

water is needed to reproduce spore lands somewhere and a small

heart-shaped prothallus appears * sperm swim through rain or dew from

antheridium (male part) to archegonium (female part) where fertilization occurs

Ferns continued ...

young sporophyte develops and grows into what we would recognize as a fern

most ferns live in the tropics but some occur in forest ecosystems

Psaronius (extinct) was several meters tall and had leaves up to 2 meters long. It had a diameter up to 30 cm.Was not made of wood but instead supported by

a mantle of extra roots and leaves.

Fern Lifecycle

Try these sites for lifecycle examples:

- New Zealand Plants - University of Aukland

- Sanata Rosa Tropicals

Images of Ferns:

- Discover Olympic

Seed-Producing

1. Gymnosperms (conifers) - 700 species most conifers are evergreens most are woody trees or shrubs with needles

or scales for leaves. This is well adapted to dry environments due to the low surface to volume ratio and thick waxy cuticle

produce naked seeds grouped in cones (attached to the upper surface of the scales)

includes juniper, larch, pine, spruce, fir

Gymnosperms continued …..

Bristlecone Pine in California and Nevada can be 4900 years old. The wood is not good for logging but tourists break pieces off to take home - Bristlecone Pine website

Redwoods of California are some of tallest trees in world. Tallest tree is 372 ft high. The largest is 273 ft high, 84 ft wide and 4000 years old.*

Ginkgos nearly went extinct but were saved by monks. They have high disease resistance and pollution tolerance

Gymnosperm Reproduction

cone cross section *

scale with seeds *

pollen grain *

Cone cross section

Scale with seeds

Pollen Grain

Seed-Producing con’t . . .

2. Angiosperms (flowering plants) - 200 000 species

flower is the reproductive structure sperm is transferred in pollen grains to the

egg within the carpel of a flower. This zygote develops into the seed, protected within a fruit. Part of the seed embryo consists of one or two modified leaves called cotyledons, and a root. The seed also has a food supply, either as endosperm or in the embryo itself.

2 classes of Angiosperms

Monocotyledons: single cotyledon in the seed embryo parallel veins in long, narrow leaves flower parts in multiples of 3 * includes grasses, sedges, cereal crops,

rice and corn important food source for humans

Dicotyledons: two cotyledons in the seed embryo branched venation in broad leaves flower parts in multiples of 4 or 5 * includes most fruits, vegetables, trees,

and shrubs

Summary

Bryophytes have no vascular tissue, need water to reproduce, and are considered to be the simplest land plants

Tracheophytes (vascular plants) have vascular tissue and do not need water to reproduce. They reproduce by seeds or by spores

seed bearing plants are considered to be more advanced than spore-bearing plants

angiosperms are considered to be the most advanced land plants

m osses liverw 's hornw 's

Bryophytes

angio's gym no's

seeds spores

Vascular P lants

Land P lants

How do plants influence the economy?

Spice Cinnamon, nutmeg, ginger, licorise

Pharmaceutical Good: White willow, coco leaves, mustard,

comphrey chamomile Bad: marijuana, opium, magic mushrooms,

cocainPoisons:

Rhubarb leaves, Stinging Nettle, Lily of the Valley, Cassava Root (Tapioca), Mtn Ash Berries

Textile Industry Cotton, Hemp

Fuel/Oil Industry Ethanol, Canola

Lumber Industry Oak, Walnut, Pine, Maple, etc.

Food Industry Fruits, Vegetables, Grains, etc.

The End

Please refer to your Kingdom Plantae Handout