1. Plants
Chapter 21

2. Plant Evolution
Plant: multicellular, photosynthetic eukaryotic organism that contains tissues and organs with specialized structures and functions
Plants share a common ancestor with green algae.
Plants developed derived traits (adaptations) to be able to live on land.
Cuticle
Stomata
Vascular tissue
Reproductive strategies
Seeds

3. PLANT
LEAF performs photosynthesis
Not pictured
Vascular tissues: specialized transport tissues that move water and nutrients from the roots to the rest of the plant; provides support
Reproductive strategies: adaptations of gametes and mutually beneficial relationships with other living things
Seeds: Seed coats protect embryo of new plants as they scatter on land
CUTICLE reduces water loss; STOMATA allow gas exchange (photosynthesis
and cellular respiration)
STEM supports plant (and may perform photosynthesis)
ALGAE
Surrounding water supports the algae
WHOLE ALGAE performs photosynthesis; absorbs water, CO2, and minerals from the water
ROOTS anchor plant; absorb water and minerals from the soil (aided by mycorrhizal fungi)
HOLDFAST anchors the algae

4. Plant Classification Two main categories:
Nonvascular Plants (earliest to diverge)
Called Bryophytes
Common examples: mosses, hornworts, and liverworts
Small plants
Lack true leaves; use root-like rhizoids to anchor them into to a surface
Live in damp, shady areas to assist in providing water to tissues
Vascular Plants (evolved later)
Seedless Plants (ferns) and Seed Plants
Contain a xylem and phloem
Have well-developed root system
Rigid stem

5. Vascular Seedless Plants - Ferns
Tend to live in damp, shady areas
Water is need for flagellated sperm to reach the egg to reproduce new generations of the plants.

6. Vascular Seed Plants
The appearance of seeds is a major evolutionary step.
Pollen grains transport sperm rather than water.
Seed Structure – protects embryo:
Seed coat: protective coating
Embryo: growing, developing new plant
Cotyledons: store food or help absorb food for the growing embryo
Monocotyledons – have one cotyledon
Dicotyledons – have two cotyledons
Location of Seeds
Angiosperms – seeds are found in a fruit
Gymnosperms – seeds are NOT part of a fruit; naked seeds

7. Gymnosperms – Naked Seed Plants
Gymnosperms diverged before angiosperms. Fruits are a more recent adaptation.
Division Coniferophyta:
Male cones produce pollen, which carries sperm.
Female cones are larger and more open to allow the sperm to collect.
Female cones remain on the plant until seeds are mature.
When the cone drops from the tree, seeds are spread.

8. Angiosperms – Fruit-bearing, Flowering Plants
Flowers are reproductive structures in plants.
Sepal: protects flower buds
Petal: attracts pollinators and provides landing pad
Stamen – MALE reproductive organ; filament supports the anther; anther produces pollen (sperm)
Pistil or Carpel – FEMALE reproductive organ; pollination occurs at stigma; embryo (SEEDS) develop in the ovary; fruits form from the ovary

9. Fruits – Seed Dispersal
Fruits are seed dispersal adaptations.

10. Categories of Angiosperms

11. Categories of Angiosperms

12. Categories of Angiosperms
Monocot is on the left
Oat plant
Dicot is on the right
Bean plant
Notice the differences in the two plants.

13. Categories of Angiosperms
In monocots, the vascular bundles in the stem cross section are usually scattered or more complex of an arrangement as compared to dicots.
The vascular bundles in the stem cross section of dicots are arranged in a circle, or ring.

14. Types of Monocots and Dicots