22-4 & 22-5 Seed Plants

Seed Plants Divided into two groups: Gymnosperms – have seeds directly on surfaces of cones Angiosperms – have seeds within a layer of tissue that protects the seeds Also called “flowering plants”

Seed Plants Why are they the most dominant plants on land? Unlike bryophytes (mosses) and ferns, seed plants don’t require H2O to reproduce As a result, seed plants can live just about anywhere, wet or dry!

Seed Plants Adaptations that allow seed plants to reproduce without water include: Protection of embryos in seeds Seed-containing structures: cones (gymnosperms) and flowers (angiosperms) Transfer of sperm by pollination

The seed Seed – embryo of plant encased in a protective covering (seed coat) and surrounded by a food supply

Tough Seeds Seeds can survive long periods of bitter cold, extreme heat and even drought by only continuing to grow when conditions are more ideal example: Desert Paintbrush (Castilleja chromosa)

Pollination Pollen grain: entire male gametophyte (sperm) Pollination: transfer of pollen from male sex structure to female sex structure by water, wind, insects, or small animals

Gymnosperms – “naked seed” Produce seeds that are exposed Cone-bearing plants Oldest surviving seed plants Include conifers (ex. pine trees), cycads and ginkgoes

Angiosperms – “enclosed seed” Flower and fruit production are evolutionary advantage Flowers Attract pollinators Contain ovaries which surround/protect seeds Ovaries develop into fruit Fruit Protects the seeds Helps spread seeds (remember the “Seedy Side of Seeds”?)

The 2 Classes of Angiosperms Monocots: embryo has one seed leaf (cotyledon) Examples: corn, orchids and palms Dicots: embryo has two seed leaves (cotyledons) Examples: roses, tomatoes, and oaks ** They have many differences…

Monocot/Dicot Table Use same piece of paper you used for the “Alternation of Generation” drawing In 2 squares underneath the “Alt. of Gen.” drawing, you will draw figure 22-25 on p.570 of “Biology” textbook Include: all headings for rows and columns, all descriptions and color all drawings