Introduction to PlantsIntroduction to Plants
A. Obstacles to living on land
Harsh ultraviolet light Harsh ultraviolet light oxygen produced in oxygen produced in oceans converted to ozoneoceans converted to ozone
Absorbing minerals Absorbing minerals mutualism with fungi, mutualism with fungi, similar to mycorrhizaesimilar to mycorrhizae
Conserving moisture Conserving moisture Waxy cuticle, with Waxy cuticle, with pores called stomatapores called stomata
Reproducing on land Reproducing on land sperm protected in sperm protected in pollen grainspollen grains
Pollen Grains
B. Vascular Tissue and SeedsB. Vascular Tissue and Seeds
Tissues to conduct materials within a plant.Tissues to conduct materials within a plant. Xylem moves water and dissolved minerals Xylem moves water and dissolved minerals
from roots to leaves.from roots to leaves. Phloem moves carbohydrates from leaves to Phloem moves carbohydrates from leaves to
roots. roots. A seed contains the embryo of a plant.A seed contains the embryo of a plant. Seeds provide advantages such as protection, Seeds provide advantages such as protection,
nourishment, dispersal, and delayed growth.nourishment, dispersal, and delayed growth.
Cladogram of Plant diversityCladogram of Plant diversity
Mosses
Vascular tissue
Ferns
Seeds
Gymnosperms (conifers)
Fruits and flowers
Angiosperms-Monocots
-Dicots
C. Phyla of Living PlantsC. Phyla of Living Plants Nonvascular plants include mosses, liverworts, and Nonvascular plants include mosses, liverworts, and
hornworts. These require water for reproduction, and are hornworts. These require water for reproduction, and are small in size.small in size.
Mosses do Mosses do
not make not make
seedsseeds
Mosses do not have xylem or phloemMosses do not have xylem or phloem
Vascular, Seedless plants include ferns and Vascular, Seedless plants include ferns and horsetails. These have xylem and phloem, horsetails. These have xylem and phloem, but do not produce seeds.but do not produce seeds.
Gymnosperms (with seeds) are primarily the Gymnosperms (with seeds) are primarily the conifers and cycads. These rely on wind for conifers and cycads. These rely on wind for pollinationpollination
Angiosperms (with flowers and fruits) are the most Angiosperms (with flowers and fruits) are the most numerous plantsnumerous plants
D. Alternation of GenerationsD. Alternation of Generations
Plants alternate between a haploid Plants alternate between a haploid gametophyte that produces gametophyte that produces gametes and a diploid sporophyte gametes and a diploid sporophyte that produces sporesthat produces spores
E. Evolution of flowersE. Evolution of flowers
Flowering plants are more efficient than conifers, Flowering plants are more efficient than conifers, because animals often carry the pollen.because animals often carry the pollen.
Flower have four basic structures:Flower have four basic structures:
A. Sepals – modified petals, protect flower A. Sepals – modified petals, protect flower while it is a budwhile it is a bud
Petals – may be scented and/or colored to Petals – may be scented and/or colored to attract attract animalsanimals
Stamen – Stamen – male male reproductive structure, with reproductive structure, with antheranther and and filamentfilament
Pistil – Pistil – female female reproductive structure, with reproductive structure, with stigmastigma, , stylestyle, and , and ovaryovary. Fertilized egg develops within . Fertilized egg develops within ovary, becomes a ovary, becomes a seedseed..
A cotyledon is a A cotyledon is a leaf-like structure that stores leaf-like structure that stores food for the embryofood for the embryo
Angiosperms are divided into two classes:Angiosperms are divided into two classes:
1.1. Plants with one cotyledon are called Plants with one cotyledon are called monocotsmonocots..
2.2. Plants with two cotyledons are called Plants with two cotyledons are called dicots.dicots.
MonocotsMonocots DicotsDicots
EmbryoEmbryo One cotyledonOne cotyledon Two cotyledonsTwo cotyledons
MonocotsMonocots DicotsDicots
FlowersFlowers flower parts are flower parts are in multiples of 3in multiples of 3
flower parts are in flower parts are in multiples of 4 or 5multiples of 4 or 5
MonocotsMonocots DicotsDicots
StemsStems xylem and xylem and phloem is phloem is scatteredscattered
Xylem and phloem is Xylem and phloem is in a ring patternin a ring pattern
MonocotsMonocots DicotsDicots
LeavesLeaves Veins are parallelVeins are parallel Veins are branchingVeins are branching
MonocotsMonocots DicotsDicots
RootsRoots Fibrous – Fibrous – numerous roots of numerous roots of approx. the same approx. the same lengthlength
Taproot – a main root Taproot – a main root with small lateral rootswith small lateral roots
MonocotsMonocots DicotsDicots
ExamplesExamples Wheat, Rice, Wheat, Rice, Grass, Grass,
DaffodilsDaffodils
Peas, Radishes, Peas, Radishes, Lettuce, Carrots, most Lettuce, Carrots, most trees (apple blossom trees (apple blossom below)below)
Monocot or dicot?Monocot or dicot?
Monocot or dicot?Monocot or dicot?
Monocot or dicot?Monocot or dicot?
Monocot or dicot?Monocot or dicot?