Plants

• Origin of plants• Key features of plants• Major groups

Kingdom: Plantae

Origin of Plants• Chlorophyta• Gave rise to land

plants

• Evidence:• DNA sequence• Chlorophyll• Store starch• Cell walls of cellulose

Key features of plants

• Multicellular• Most are autotrophic• Reproductive cycle• Alternating multicellular haploid and diploid

generations• Sporophyte: Diploid• Gametophyte: Haploid, male and female

Life on land

• Problems include• Lack of buoyancy• Drying out• Reproduction

Key Adaptations• Roots to absorb water

and support• Waxy cuticle to prevent

drying out• Pores called stomata to

allow photosynthesis without drying out

• Conducting vessels• Lignin for support• Pollen• Seeds• Fruits for

dispersal/protection

Reproduction in Plants

Major groups

Evolution of plants

Bryophytes

• Non-vascular• Seedless• Small size• Needs water for

reproduction

Mosses and Liverworts

Seedless vascular plants

• Club mosses• Horsetails• Ferns• Sporophyte is

dominant• Ancient plants

(carboniferous forest)

Reproduction

Fern, club mosses & Horsetails

Seed Plant

• Gymnosperms• Angiosperms

(flowering plants)• Dicots and Monocot

• Two major adaptations:

• Seed • Pollen

Adaptations

Gymnosperms

Groups

Cycad Ginkgo

Plants Under the Hot Sun

Angiosperms

• Flowers• Fruits• Annual plants

Life Cycle

Pollinators: Mutualism

Eucalyptus trees