Several important evolutionary adaptations (or conditions) occurred that helped to make the invasion of land by plants permanent. Which of the following is NOT one of those changes?

a) Evolution of a water‑impermeable cuticle.

b) Evolution of a chlorophyll as a pigment for photosynthesis.

c) Evolution of protective layers for the gamete‑bearing structures.

d) Initial absence of herbivores.

e) Development of tracheids.

Figure 30.2. Variations on gametophyte/sporophyte relationships

Figure 30.3 From ovule to seed

Winged seed of a White Pine (Pinus strobus)

Chapter 30. Plant Diversity IIThe evolution of seed plants

30.1. A seed consists of the embryo, its food supply and a protective coating.

epiphytes

Chapter 30 Key Concepts

• Seeds and pollen grains are key adaptations for life on land

• Gymnosperms bear naked seeds, typically on cones

• Flowers and fruit are adaptations of angiosperms

• Human welfare (including healthcare) depends greatly on seed plants

“Hotlips”Heliconia

Figure 29.7 Some highlights of plant evolution

Match the derived characters listed below with the correct branch point in the diagram

a. Flowers

b. Embryos

c. Seeds

d. Vascular tissue

Hypothetical phylogeny of the seed plants

Winged seed of a White Pine (Pinus strobus)

Pollen grains (male gametophyte enclosed within a pollen wall)

30.5 Gymnosperm diversity(see also p. 622)

(Naked seeds - lack ovaries where eggs develop)

Phylum Ginkgophyta: Ginkgo biloba[maidenhair tree]

30.5 Phylum Ginkgophyta: Ginkgo biloba

Ginkgo: Male (left, pollen), female (right, seeds)

Hypothetical phylogeny of the seed plants

30.6 Phylum Cycadophyta: cycads (“sago palms”)

30.7 Phylum Gnetophyta: Welwitschia

Gnetophyta: Ephedra sp.(arid regions)

Ephedrine used medicinally as decongestant, stimulant or appetite suppressant.

(Chemically almost identical to amphetamine and methamphetamine)

Hypothetical phylogeny of the seed plants

30.5 Gymnosperm diversity(see also p. 623)

Phylum Coniferophyta: Douglas fir

Phylum Coniferophyta: Sequoia

Phylum Coniferophyta: Cypress swamps

Phylum Coniferophyta: ‘Lone Cypress’, Monterey California

Phylum Coniferophyta: Pacific yew

Phylum Coniferophyta: A pine farm

Bristlecone Pine(some of the oldest living organisms)

Fir: Ovulate cones

Pinus: pollen cones

Figure 30.6 The life cycle of a pine

Figure 30.6 The life cycle of a pine

Figure 29.5 Alternation of generations: a generalized scheme

Figure 30.6 The life cycle of a pine

Pine Sporangium with spores

Pine pollen

Pine embryo

Gymnosperms and angiosperms have the following in common, except

a) Seeds

b) Pollen

c) Vascular tissue

d) Ovaries

e) Ovules

Figure 29.7 Some highlights of plant evolution

Figure 30.13 Representatives of major angiosperm clades (Anthophyta)

Monocots – (Eu)dicots

Figure 30.13A comparison of monocots and Eudicots

Xylem cells in angiosperms(see also 35.10)

Perfect flowers: Both male and female parts(as opposed to imperfect flowers)

Mono-ecious: Both male and female flowers occur on the same plant(as opposed to di-ecious plants with truly female and male plants)

30.7 The structure of a flower

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

30.8. Some variations in fruit structure

Figure 30.9 Fruit adaptations (shape, color, smell, time of flowering, etc.) that enhance seed dispersal:red berries (left), dandelion (right)

Dandelion seed dispersal

A bird eating berries containing seeds that will be dispersed later with the animal's feces

30.9.

30.14, 30.15. Flower-pollinator relationships: Scottish broom flower and honeybee (left), hummingbird (middle), baobab tree and bat (right)

30.10 The life cycle of an angiosperm

Flowering plants - Double fertilization

Why protect this diversity?

Human welfare depends greatly on plants!

Table 30.1A sampling of medicines derived from plants.

In the U.S., some 25% of prescription drugs contain active ingredients extracted directly from plants. Other ingredients were first discovered in plants and then synthesized artificially

The rosy periwinkle (Catharanthus roseus): a plant that saves lives

Pacific yew (Coniferophyta) – Taxol (ovarian cancer drug)

Eucalyptus – Menthol (ingredient in cough medicine)

Poppy (Papaver somniferum) - opiatesMorphine , codine (pain relievers), heroin (synthesized from morphine)

Deforestation is an international practice

Deforestation

Deforestation of tropical forests

Deforestation in the United States

Fragmentation of a forest ecosystem

Chapter 30 Review

1. Seeds and pollen grains are key adaptations for life on land

2. Gymnosperms bear naked seeds, typically on cones

3. Flowers and fruit are adaptations of angiosperms

4. Human welfare (including healthcare) depends greatly on seed plants

One of the major functions of double fertilization in angiosperms (flowering plants) is to

• emphasize embryonic survival by increasing embryo size.

• increase the number of fertilization events and offspring produced.

• promote diversity in flower shape and color.

• decrease the potential for mutation by insulating the embryo with other cells.

• coordinate developmental timing between the embryo and its food stores.