Transcript Plant Kingdom Notes

Kingdom Plantae
General Characteristics
• Use photosynthesis to gain energy, therefore
autotrophic.
• Live in all aquatic and terrestrial habitats except
at the poles.
• Are the main source of oxygen for the planet
• The basis for every food chain or food web
Classification of Plantae
• Although there are a vast variety of plants in the
world, they can all be placed in one of four main
groups.
• Each large group contains several divisions, which
are the rough equivalent to a Phylum.
1) Non-Vascular Plants (Mosses and their
relatives)
• Three divisions (mosses, hornworts and
liverworts).
• No vascular tissue, therefore depend on
osmosis and diffusion to transport nutrients.
• Usually grow in dense mats of low tangled
vegetation that can hold water like a sponge,
allowing them to survive cold or dry periods.
• Have no roots, instead have root-like
rhizomes.
• Sexual reproduction.
Non-vascular Plants
Mosses (Bryophytes)
•
Very successful and widespread as they thrive in such
diverse habitats as bogs, tundra, on bare exposed rocks,
and in deep shade.
•
Twice as many species of mosses as there are mammals!
Liverworts (Hepatophytes)
•
Grow flat, low to the ground and are rarely more than 30
cells thick.
•
80% are leafy and live in tropical forests and in humid
climates.
•
Thallose liverworts are the other 20%.
•
Many small chloroplasts per cell.
Hornworts (Anthocerophytes)
•
Broad, flat and are commonly blue-green in colour.
•
One large chloroplast per cell
2) Seedless Vascular Plants (Ferns and their
relatives)
• came about 300 million years ago
• developed the vascular tissue that allowed them to
grow tall
Seedless Vascular Plants
Whisk Ferns (Psilotophytes)
• Look like small green whisk brooms
• No leaves or roots
• Short rhizomes, which are horizontal,
underground stems.
• Produce spores.
Club Mosses (Lycopodophytes)
• Small evergreen-looking plants that grow in
dense mats in moist temperate or tropical
forests.
• Not related to true mosses!
• Have true roots and stems.
Seedless Vascular Plants
Horsetails (Sphenophytes)
•
Once included tree-sized members, but now just
smaller plants (1 m).
•
Often found in damp areas or along roadsides.
•
Can be used to scour pots.
•
Have silica in their cells, which accounts for the
roughness.
•
Can be made into a shampoo to combat head lice.
Ferns (Pteridophytes)
•
Dominated the forests during the Carboniferous period
(315-280 mya).
•
Most familiar and successful of the seedless vascular
plants.
•
Have roots, stems, a waxy epidermis that reduces water
loss by evaporation and stomata in their leaves for gas
exchange.
•
Ferns produce millions or even billions of spores in their
lifetime.
•
Have fronds, which are seed leaves that grow up from
rhizomes.
3) Gymnosperms (Conifers and their
relatives)
• disperse by means of seeds
• reproduce sexually without
needing water
• have seeds that are exposed on the
surface of cone scales
• gymnosperm means ‘naked seed’
• includes cone-bearing trees: pines,
firs, spruce, yew, cedars, redwood
and many other large trees.
• Also includes the cycadophytes,
gnetophytes and ginkgophytes.
Gymnosperms
Conifers
•
Form vast forests in the colder regions of the world
•
As well as reproducing without water, they have bark to
prevent water loss.
•
The pyramidal shape of many conifers helps snow and
ice slide off the tree reducing branch breakings.
•
The needle like leaves have a thick, waxy cuticle and
sunken stomata, which reduce the rate of evaporation.
•
These are evergreens, which are continually losing and
replacing needles all year round.
Gnetophyta
•
Very rare, found in southern Africa
Gymnosperms
Cycadophyta
•
100 species in the tropics, once
dominated the earth.
•
Short, palm-like trees with scaly
trunks.
Ginkgophyta
•
The only living species is Ginko
biloba, which was common
during the Jurassic period (200
mya).
•
Cultivated in Asian temples for
hundreds of years, which
helped protect against
extinction.
4) Angiosperms (Flowering Plants)
• Plants that protect their seeds within the body
of a fruit are called angiosperms or flowering
plants.
• Appeared on earth more than 150 mya.
• Include vines, grasses, shrubs, trees and water
plants.
• Grow everywhere on land from tundra to
tropics.
• Divided into monocots (1 seed leaf) and dicots
(2 seed leaves)
• Sexual reproduction by pollination. Use wind,
water, animals, bats, birds and insects as pollen
carriers.