Chapter 30: Plant Diversity The Evolution of Seed Plants 30.1 Admit Slip 3. List 3 words you think of when you look at the picture/diagram 2. Write 2 ideas you have based on the picture and your words. If possible, use your words as you write your ideas. 1. Write 1 question you have.

Seeds and Pollen Grains are Key Adaptations for Life on Land Seeds are plant embryos that have a food supply and are surrounded by a protective coat

5 Crucial Seed Plant Adaptations Reduced gamteophytes: microscopic, dependent on sporophyte for food and protection Heterospory: production of 2 types of spores Megaspores: female gametophytes-produce eggs Microspores: male gametophytes-contain sperm Ovules and the production of eggs: Increases protection of the egg and developing zygote

5 Crucial Seed Plant Adaptations Pollen and production of sperm: pollen grains have water-proof coating which eliminates the need for water transfer of sperm. Inside the pollen grain is a male gametophyte with 2 sperm nuclei. Seeds: multicellular, safe-guarding of embryo, stored energy for embryo, can remain dormant while awaiting good germination conditions

Chapter 30: Plant Diversity The Evolution of Seed Plants 30.2

Evolutionary trends in land plants Reduction in gametophyte bryophytes pteridophytes gymnosperm angiosperm

Gymnosperms “naked” seed, seeds not enclosed in ovaries, (usually on modified leaves that form cones) No fruits

Gymnosperm life cycle

Pollination and Fertilization Pollen lands on ovulate cone, drawn into micropyle germinates; grows a pollen tube Fertilization Embryo develops Cones open, seeds released 2009

Chapter 30: Plant Diversity The Evolution of Seed Plants 30.3

Angiosperms Seed plants that produce flowers and fruit 90% of all plants are angiosperms

Angiosperms Flower structures: Stamen: male reproductive structure-produces microspores that develop into pollen grains Carpels: female reproductive struction-produces megaspores and products (female gametophyte and egg)

Figure 38.9 Growth of the pollen tube and double fertilization 2009

Angiosperm life cycle 2009

KEY FEATURES: Double Fertilization 3n endosperm 2009

Mature ovaries of plant Angiosperm Fruits Mature ovaries of plant After fertilization, the seed develops from ovules. The wall of the ovary thickens to become fruit. Fruit helps to disperse seeds

2009

SEED DISPERSAL

Angiosperm Classification Monocot: 1 cotyledon in seed Parallel leaf veination Flowering parts in multiples of 3’s Eudicot 2 cotyledon in seed Net leaf veination Flowering parts in multiples of 4’s and 5’s

Monocots vs. dicots 2009

2009

Land Plant Evolution