1

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 can’t transport water

very well…what 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

5

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

6

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

7

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

8

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)

9

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

10

Pollen grainsFig. 15.5

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

Angiosperm Lifecycle

Fig. 15.14 Angiosperm Vascular Tissues

11

Vascular tissue- Roots Vascular tissue- Stems

Angiosperm leaves How does Vascular tissue work?

Pollen dispersal- Smart delivery devisesSeed Dispersal

12

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

The Angiosperm’s other trick… Fruits Animal Dispersal

Table 15.1