Plants

Kingdom Plantae

Eukaryotes

Possess cellulose-rich cell walls, store starch

Have chloroplasts containing chlorophylls a and b, carotenoids

Multicellular

5 derived characters (synapamorphies):

     1. apical meristems in shoots and roots Fig. 29.3

     2. multicellular dependent embryos Fig. 29.4

     3. alternation of generation Fig. 29.6

     4. walled spores produced in sporangia Fig. 29.8. A fern spore - Fig. 29.7

     5. multicellular gametangia Fig. 29.9

Charophyceans (Chlorophyta) - Chara - Fig. 29.2a

Evolved from a green alga called a charophycean, a type of Chlorophyta

Homologies between green algae and plants

     Similarities in chloroplasts

     contain chlorophyll a & b and carotenoids

     DNA and RNA sequence analyses indicate that green algae are the ancestors  of all plants.

Homologies between chaophyceans and plants     

     have similar cell division to higher plants - cell plate formation (phragmoplast - Fig. 12.8)

     have same enzymes in peroxisomes to minimize loss of organic product due to photorespiration

     rosette cellulose-synthesizing complex

     plants with sperm have sperm similar to charophyceans

The Green Invasion of the Land - these enabled a terrestrial existence rather than aquatic.

• cuticle Fig. 29.10 and Fig. 35.19
• stomata Fig. 10.2
• strengthening chemicals like lignin
• protection of gametes and embryos - gametangia

The Plant Life Cycle

     Alternation of Generations Fig. 29.6

Alternation of diploid sporophyte and haploid gametophyte

Generalized life cycle:

• In sporophyte, meiosis produces haploid spores
• Spores divide by mitosis to produce haploid gametophyte
• Gametophyte produces haploid gametes
• Gametes fuse forming diploid zygote
• Zygote mitotically divides to form sporophyte

Trends in the evolution of the plant life cycle - from flagellated sperm & spores, to pollen and seeds. Also from a dominant gametophyte to a dominant sporophyte. Fig. 30.1

A phylogeny for plants. Fig. 29.1. Also see Table 29.1

Mosses, Liverworts and Hornworts = Bryophytes (traditional name) - Fig. 29.15

• Life cycle of a moss Fig. 29.16. See the movie
• Gametophytes nutritionally independent of sporophyte but sporophyte nutritionally dependent on gametophyte
• Flagellated sperm
• No vascular tissue

Features of Vascular Plants - General characteristics

• Large, dominant, nutritionally independent sporophytes
• Specialized leaves, stems, roots.
• Vascular system

Seedless Vascular Plants

     Pterophyta: The Ferns Fig. 29.21- life cycle Fig. 29.23. See the movie

• Earliest vascular plants lacked seeds - produced spores
• Flagellated sperm
• Dominated during the Carboniferous - this forest consists almost entirely of Pterophyta that produced the coal we use today. Fig. 29.25

Seed Plants

• Produce pollen and seeds. Fig. 30.2: From ovule to seed
• Embryo protected within coat of sporophyte tissue
• Derived from single, common ancestor
• Two major groups Fig. 30.4

         Gymnosperms

         Angiosperms, flowering plants

Gymnosperms - Naked seeds

• Dominant in the Mesozoic
• The Pine Life Cycle Fig. 30.9 - Pine Life cycle - the movie! Conifers - Fig. 30.8b - seeds in cones
• Pine seed Fig. 30.3     Male cones Fig. 30.10a1        Pine pollen Fig. 30.10a3      Pine female cone Fig. 30.10b1

Angiosperms - flowering plants - seeds enclosed in ovary

• Major clades - Fig 30.11
• Ovules enclosed by sporophytic tissue
• Flowers - Fig 30.13a (Time lapse flower movie) and fruit - Table 30.1
• Angiosperms exhibit unique process of double fertilization -image 1 and image 2 image 3 Fig 30.17 (life cycle) The Movie!
• Also coordinates developmental timing between embyo and food stores.

Unique characters that made Angiosperms successful

• Pollination by animals: coevolution - Fig 30.18 Movie - Bee movie
• Double fertilization
• Fruits
• Dispersal of seeds by animals

Plant diversity is a non-renewable resource. Some medicines derived from plants. - Table 30.2 (Do NOT need to memorize table). Deforestation - - Fig 30.19