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Kingdom Plantae The Plants- Kingdom Plantae

Multicellular, eukaryotic, photosynthetic, autotrophic

All have: Chloroplasts, evolved from single-celled green

algae Non-motile, rigid cell wall, sexual reproduction Require light, water, minerals, CO2, other stuff

which they must get from their environment

The First Plants- The Algae

Plant evolution begins in the sea Single celled Multicelled colonies

But still have very little specialization between cells

Three divisions of algae- all can be seen in tide pools

Rhodophyta- Red Algae Phaeophyta- Brown Algae Chlorophyta- Green Algae

Life cycles of most algae

2 multicellular phases- Alternation of Generation

2n n 2n n.etc. Sporophyte and Gametophyte One phase may be dominant in structure Example on board and overhead

General Algal /Plant lifecycle Plants move onto LandAdvantages Low competition Low predation Ample sunlight Ample landscape Higher CO2

Challenges Motile sperm need water No water to hold up body H2O, minerals- absorb and

transport issues Desiccation Dispersal problems Temperature changes Need to protect embryos

2

Water vs. Land

Evolution of Land Plants All land plants evolved from Division

Chlorophyta, or the Green Algae Photo pigments- Chl. a & c, Carotinoids Store food as Starch

Bryophyta- The Mosses and Liverworts

1st terrestrial plants Non-vascular- so they cant transport water

very wellwhat does this mean? Motile sperm- Need water to reproduce Small size, gametophyte is dominant Must live near water in a moist habitat!

Bryophytes Sphagnum, or peat moss: Peat bog in Oneida County, Wisconsin

3

A peat moss bog in NorwayBryophyte lifecycle

The Vascular PlantsAdaptation Trends of Vascular Plants Roots- obtain H2O and nutrients Vascular tissue

Xylem- H2O and nutrient transfer Phloem- sugar transport

Cuticle- prevents drying Stomata-prevent drying and helps gas ex. Leaves- efficient photosynthesis

The Vascular Plants, cont.

Xylem and Lignin- support for tall stems Hormones- coordinate growth, help with

changing conditions Pollen- replaces motile sperm- how get

around? Wind or animals Seeds- protects and dispersal of next gen. Fruits- enhance dispersal- animals Flowers- amt. pollen, pollination/fert.

4

Ferns, club mosses, horse tails

Ferns Large, many-veined leaves= Fronds Rhizome- underground stem w/ roots Dominant Sporophyte w/ vascular tissue.

Independent gametophyte- Vulnerable, no roots Still has motile sperm-Needs moist environment Most gametophytes die or are eaten

25 million year period of drought and glaciation 280 mya. Strong selection pressure for desiccation resistance

Horsetail

Fern Sorus and SporangiumThe life cycle of a fern

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Life cycle of a fern: mature sporangium Life cycle of a fern: germinating

Life cycle of a fern: gametophyteFig. 15.14

The stem of a fern Xylem and phloem in the stem of a fern

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Carboniferous forest based on fossil evidence

The Gymnosperms- Pines

The first truly terrestrial plants Reduced and retained gametophytes-Cones Separate sexes- self fert, outcrossing, gen. vari. Pollen- non-motile sperm- Wind- random, expensive Seed- Sporophyte embryo- 3 generations

nourished and protected Needles- low evaporation Slow life cycle- 7-10 years

Vascular tissue

Stem Tissues Sequoia

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Sequoias Cypress

Common juniper Bristlecone Pine

Oldest Living Trees

4,766 years old!!!

The life cycle of a pine The life cycle of a pine

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The life cycle of a pine

Fig. 15.14

Male pine cones Pine Sporangia with sporesPollen

Pine pollen Winged seed of a White Pine (Pinus strobus)

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Pine embryo

The Angiosperms- Flowering Plants

Cone Flower: Flower Power! Attractive colors, nectar, pollen- All for animals! Specific coevolution Non-random, efficient fertilization

Gameto- dependent Leaves with stomata Short life cycle- Fruit- efficient dispersal Increasing specialization of vascular tissue

The typical angiosperm plant

The structure of a flower

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Pollen grainsFig. 15.5

Relationship between a pea flower and a fruit (pea pod)

Angiosperm Lifecycle

Fig. 15.14 Angiosperm Vascular Tissues

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Vascular tissue- Roots Vascular tissue- Stems

Angiosperm leaves How does Vascular tissue work?

Pollen dispersal- Smart delivery devisesSeed Dispersal

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Fruit adaptations that enhance seed dispersal: Red berries (left), dandelion (right) Dandelion seed dispersal

The Angiosperms other trick Fruits Animal Dispersal

Table 15.1