kingdom plantae national geographic - plants. kingdom plantae what are plants? most are autotrophs...
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Kingdom
PlantaeNational Geographic - Plants
Kingdom Plantae
• What are plants?
• most are autotrophs
• eukaryotic
• have cell walls containing cellulose
• mostly land dwelling organisms
• they are the foundations of almost all ecosystems.
Non-flowering
Plants
Flowering
Spore-bearing
Naked seeds
No roots
with roots
Mosses Ferns
Gymnosperms
1 seed-leaf
2 seed-leaves
Monocots Dicots
Evolution of Plants
• ancestors of modern day plants were aquatic organism similar to green algae.
• to grow on land, plants have developed:
• an embryo – reproductive structure which develops directly into a plant.
• ability to stand upright and reach for the sun
• tissues to transport water, nutrients and wastes.
• strategies to reduce water loss
• strategies to disperse seeds without relying on water currents.
• flowering plants are the youngest in plant evolution.
Alternation of Generations
• most plants have a life cycle that alternates between diploid and haploid forms.
• diploid (2 sets of chromosomes – 1 from each parent)
• haploid (1 chromosome set)
Classification of Plants:
• there are 5 major groups of plants:
• green algae
• mosses and relatives
• ferns and relatives
• seed plants
• flowering plants
1. Green Algae – modern relatives of plant ancestors
• many species are found in shallow fresh water – edges of ponds
2. Mosses and Relatives – seedless non-vascular plants
• (Bryophytes)
• grow close to the ground in damp locations where can easily obtain water.
• no seeds or stems – no rigid support structures in cell walls, so can’t grow tall.
• non-vascular – can’t transport water or nutrients within.
• male and female gametes are produced in separate reproductive structures - sperm have flagella and swim through water to the eggs.
MossesSpore-producing capsule
3. Ferns and Relatives – seedless vascular plants
•have vascular structures to carry water.
• gives advantage: can grow taller – reach the sunlight
•vascular structures (veins) connect shoots above ground to roots below
• seedless: reproduce much like mosses – sperm swims to egg on a film of water on the underside of the plant.
4. Gymnosperms – seed plants
• conifers (pine, fir, cedar, ginko)
• ‘naked seeds’ – not protected or enclosed in an ovary.
•seeds are plant embryos packaged in a protective coat along with a food supply.
• pollen grains are small male gametophytes that contains cells that develop into sperm.
• wind carries the pollen grains to female cones – where eggs develop.
5. Angiosperms – flowering plants
• reproductive structures are flowers
• 2 groups: monocots and dicots
• ovaries within flowers completely protect the seeds.
• gametophytes of angiosperms develop within the flowers
• flowers have many adaptations to disperse pollen and seeds.
• insects, animals, birds (and wind) all transfer pollen from one flower to another.
• once pollination occurs the ovary develops into a fruit – the ripened ovary of a flower.
• fruits are a good way to disperse seeds:
• if ingested, the seed survives and drops elsewhere
• burrs stick to animal fur.
• maple keys are suited to wind dispersal
• coconuts are well suited to water dispersal
MonocotyledonsMonocotyledons DicotyledonsDicotyledons
Flowering Plants
MONOCOTS vs. DICOTS
MONOCOTS10 % of monocots (one
seed leaf) have a woody stem (rigid). Examples include bamboo and palm trees.
MONOCOTSMost have a herbaceous
stem (soft, fleshy).
These include lilies, tulips, orchids, etc.
DICOTSDicots are deciduous
trees. They are considered to be
“hardwood” and also provide a large amount of money to Canada in the lumber industry.
DICOTSDicots are often used to make furniture, hockey sticks,
and provide fuel for heating purposes.
A typical salad contains many dicots (lettuce, tomatoes, radishes).
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