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?