Download Biology Notes: Chapter 13

Biology Notes, Chapter 12a, page 1
Biology Notes: Chapter 13
I. Plant Classification
A. Botany: study of plants
B. Kingdom Plantae -- Characteristics
1. organized into tissues (cells grouped according to function)
2. cell wall -- rigid boundary composed of cellulose
3. autotrophic -- performs photosynthesis (conversion of light energy to chemical
energy)
4. sessile
5. reproduction -- sexually by gametes -- asexual usually by spores
C. Phyla -- divisions determined by presence of vascular tissues (structures that conduct
water and dissolved materials in plants) and seeds
1. Bryophyta: non-vascular plants
2. Tracheophyta: vascular plants
a. Sub-phylum Pterophyta: non-seed producing vascular plants
b. Sub-phylum Coniferophyta: cone-bearing vascular plants
c. Sub-phylum Anthophyta: flowering vascular plants
II. Bryophyta
A. Characteristics
1. 25,000 types including mosses and liverworts
2. Limited in size because of the lack of tubes to carry water.
B. Example: Mosses
1. The structures of a moss:
a. rhizoids: root-like structures
b. sporophyte: produces spores
c. antheridium: produces sperm
d. archegonium: produces ova
e. leafy shoots: leaf-like structure of single-cell thickness
2. Reproduction of a moss
a. Alternating reproductive cycles in generations:
b. The zygote grows into the sporophyte which produces spores.
c. The spores grow into leafy shoots.
-- top of each shoot is either an antheridium or an archegonium.
-- gametes produced on the leafy shoot fertilize each other to produce a zygote.
III. Pterophyta: 12,000 types including ferns
A. Example: Ferns
1. Structures of a fern
a. frond: leaf-like structure of a fern
b. fiddle-head: immature frond
c. rhizome: underground stem of a fern
d. sporangia: produces spores; located on the underside of frond
Biology Notes, Chapter 12a, page 2
e. prothallus: heart-shaped structure that produces sperm and ova
2. Reproduction of a fern: alternating reproductive cycles
a. Sporangia produces spores.
b. Spores germinate and form prothallus.
c. Prothallus produces sperm in the antheridia and ova in the archegonia.
d. Sperm swim to ovum and fertilizes it.
e. The zygote matures and grows rhizomes and fronds.
f. The fronds grow sporangia.
IV. Coniferophyta
A. 600 types in the following families:
1. pine family: have needles and cones
2. yew family: waxy green needles; produces red fruit like open-ended berries
3. cypress family: overlapping evergreen scales instead of needles
4. redwood family: largest conifers
B. Conifers are a group of gymnosperm plants. Gymnosperm plants produce seeds which are
not enclosed in an ovary when mature.
1. Structures of a conifer
a. pollen cone: produces male gametes; cones are smaller and found near the tips of
the branches; the most numerous cone
b. seed cone: produces the female gamete; cones are large with open scales to
receive pollen; scales close once ova is fertilized; once seeds mature, scales open
to release them
2. Reproduction is always sexual
V. Anthophyta
A. 300,000 types divided into two groups:
1. monocot
a. produces seeds with one cotyledon (stored food section)
b. leaves have parallel leaf venation (vein pattern)
c. floral parts are in multiples of threes or sixes
d. fibrous roots
e. Examples: orchid, cattail, grass, palm, lily
2. dicot
a. produces seeds with two cotyledons
b. leaves have netted venation
c. floral parts are in multiples of fours or fives
d. usually a tap root
e. Examples: dandelion, oak, rose, orange tree, cactus
B. Reproduction in anthophyta is always sexual
1. All seeds are enclosed in an ovary and flowers.
2. A mature ovary is a fruit.
I. Plant Organs and Tissue types
Biology Notes, Chapter 12a, page 3
A. Plant Growth Pattern
1. Annual -- life cycle through one season
2. Biennial -- life cycle through two seasons
3. Perennial -- life cycle through several seasons
B. Tissue Types:
1. Meristematic -- found in the growing areas; buds, tips of roots and
stems
2. Vascular tissues -- xylem and phloem tissue
a. Xylem tissue: long, thick-walled cells that carry water and dissolved minerals;
moves materials upward from roots
b. Phloem tissue: thin-walled cells that carry water and dissolved sugars; moves
materials downward from leaves
3. Structural tissues: produce food, cover, support and protection for plant; ex. leaf,
root, stem
II. Leaf Structure
A. Venation -- vein pattern
1. Parallel venation: veins start at the stem and proceed to the top of the leaf in a
roughly parallel fashion
2. Netted venation: large veins that branch to form a network of smaller veins
a. Pinnate: veins branch off one large central vein
b. Palmate: veins branch off two or more main veins
3. Diagram page 302 - 303
B. Covering
1. Epidermis -- one-cell layer covering of leaf
2. Cuticle -- waxy substance over the epidermis
3. Stomata -- openings on underside of leaf that allows the exchange of gases
4. Guard cells -- cells around stomata; when turgid (filled with water) they open the
stomata; when lacking water they collapse and close the stomata
C. Internal Structure
1. Palisade mesophyll: Top layer of cells
a. Tightly packed, orderly cells
b. Much greener that underside of leaf because it has more chloroplasts
2. Spongy mesophyll: Under side of leaf
a. Loosely packed cells
b. Multiple air spaces for the exchange of gases
3. Collenchyma: supporting tissue for the vascular tissues
4. Diagram pg 303
D. Classification by leaves
1. Deciduous: lose leaves every year
2. Evergreen: keep leaves year round
E. Modified leaves include tendrils, needles, spines, and aquatic leaves
Biology Notes, Chapter 12a, page 4
III. Root Structure
A. Types
1. Taproot system: has a predominant root
2. Fibrous root system: has many secondary roots
B. Internal Structure:
1. Root cap: dead cells that protect new growth
2. Meristematic region: area where new cells are being formed by mitosis
3. Elongation region: area where cells mature to full size
4. Maturation region: area where cells differentiate into tissues types (such as xylem,
phloem, collenchyma, etc.)
5. Diagram pg 306
C. Growth in the root takes place in the Meristematic region
D. Tissue Types
1. Cortex: stores food in young roots
2. Endodermis: strains nutrients as they enter root
3. Vascular cylinder: bundles of vascular tissues
E. Root modifications: Storage (taproots, carrots, beets, radish, sweet potatoes), adventitious
(vines), aerial (orchids, bromeliads), aquatic (water lilies)
IV. Stem Structure
A. Purposes of stem are to hold leaves and transport water
B. Growth:
1. Bud: new stem growth
2. Bud scale scar: shows record of growth of branch
C. Two types of stems: herbaceous and wood
1. Herbaceous: non-woody stem without cork cambium
a. Pith: flesh of herbaceous stem
b. Vascular bundles: xylem and phloem tissues
2. Wood: dead layers of xylem tissue
a. Heartwood: center of woody stem; dark wood; no longer
conducting water;
oldest part of stem
b. Sapwood: middle layer of stem; light wood; conducts sap (water and sugars)
c. Bark: Outer most layer of stem
-- cork cambium: inner bark where phloem tissue is produced
-- cork: outer bark that protects stem
d. Annual rings: record of growth in woody stems
3. Modified stems
a. tuber: storage stems; ex. potatoes
b. rhizomes: thick stem that produces fronds and branches; ex. ferns
c. stolon: underground thin stem that produces secondary roots; ex. crabgrass
d. bulb: layered storage leaves; ex. tulip