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Presentation on theme: "Plants."— Presentation transcript:

1 Plants

2 Classification Timeline
500 million years ago: Algae Example: Blue-green algae 425 million years ago: Land plants (bryophytes) Example: Mosses 375 million years ago: Vascular seedless plants (pterophytes) Example: Ferns 200 million years ago: Vascular seeded plants (gymnosperms) Example: Pine Trees 130 million years ago: Flowering plants (angiosperms) Example: Daffodils

3 Non-vascular plants: Algae
Non-vascular- no tubes to transport water & nutrients or provide support All movement occurs through osmosis Aquatic Can photosynthesize- use sunlight to produce its own energy Essential source of oxygen in aquatic ecosystems (70-80% oxygen comes from algae)

4 Non-vascular plants: Bryophytes
Bryophytes- non-vascular plants No tubes to transport water & nutrients or provide support to the plant All movement occurs through osmosis No true stems, leaves, or roots Rhizoids act as roots- absorb water & minerals Need water to reproduce Less likely to survive harsh conditions because of need for water

5 Vascular Plants: Pterophytes, Gymnosperms, & Angiosperms
Contain vascular tissue Xylem & Phloem Xylem transports water Phloem transports sugars Pterophyte Gymnosperm Angiosperm

6 Angiosperm Classification: Monocot vs. Dicot

7 Angiosperm Classification: Alternate vs. Opposite Leaves

8 Roots Purpose Increase surface area to absorb more water & minerals
Anchor plant Store water & minerals

9 Types of Roots Tap- one main root that goes straight down
I.e. Carrot Fibrous- has root hairs or lateral roots Aerial- roots exposed to air aerial

10 Parts of the Root Cross section Root hair- increase surface area to absorb more water & minerals Epidermis- protection & absorption Cortex- Movement of water & minerals to center of root Storage of food Endodermis- assists in movement of water & minerals to center of root Xylem- movement of water Phloem- deliver food to root Apical meristem- area of growth Root cap- protection & helps root elongate farther into soil Longitudinal

11 Herbaceous Stem Contains vascular bundles
Monocot- vascular bundles spread throughout Contains vascular bundles Xylem & phloem Xylem (inside of vascular bundle) Dead cells Main purpose to move water through the stem Phloem (outside of vascular bundle) Alive at maturity Main purpose to move sugars down through stem Cortex Water & minerals transported Epidermis Protection Dicot- vascular bundles in a ring

12 Woody Stems Consists of sapwood & heartwood
Heartwood- xylem that no longer transports water, provides support Sapwood- xylem that still transports water

13 Woody Stems: How Tree Rings Form
Vascular cambium Layer outside of wood Create new xylem every year in the spring & the summer (tree rings!) Indicator of weather Good season, wider ring Bad season, narrower ring

14 Woody Stems: Bark Bark- includes cork & phloem
Vascular cambium creates new phloem Cork cambium produces new cork (bark that we see)

15 Leaf Cross Section Leaves Cuticle- waxy covering; prevents drying out and provides support Stomata- opening for gas exchange Guard cells- open & close stomata Vein Contains xylem & phloem Xylem- transport water Phloem- transport sugar Palisade- packed closely together- photosynthesis Sponge- open spaces- allow gas exchange within leaf

16 Stomata Opens to allow gas exchange between plant and atmosphere
Open- photosynthesis, at risk to dry out Closed- no photosynthesis, maintains moisture

17 Water Movement in Plants
Root pressure Moves water through osmosis Works up to 1 meter Capillary Action Movement due to small area Cohesion & adhesion Cohesion- water sticks to itself Adhesion- water sticks to walls of xylem

18 Water Movement in Plants
Transpirational Pull Main source of upward water movement in plants Water evaporates from stomata in leaves Water moves up plant to replace lost water Occurs through cohesion & adhesion If guard cells open longer, greater transpirational pull

19 Food Movement in Plants
Food (glucose) moves downward starting from the leaves _________: vessel that transports glucose

20 Plant Hormones Have specific receptors that enable specific responses
Auxins Stimulate cell elongation & suppresses growth of lateral (side) buds Enables plants to bend toward light

21 Plant Hormones Gibberellin
Stimulate stem elongation by stimulating cell division & elongation

22 Plant Hormones Cytokinin
Stimulates growth of lateral (side) buds and release apical dominance (more growth on sides of plant rather than at the top) Stimulate flowering

23 Plant Hormones Abscisic acid (ABA) Inhibits plant growth (short)

24 Plant Hormones 5. Ethylene Promotes fruit ripening and flower opening

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