Gymnosperms and Angiosperms

Gymnosperms

seed-producing plants with “naked” seeds not enclosed in an ovary

Spermatophytes

seed-producing plants including gymnosperms and angiosperms

Seed

structure containing an embryo, food supply, and protective seed coat

Pollen

male gametophyte that carries sperm without needing water

Evolutionary advantage of pollen

eliminates need for water for fertilization

Evolutionary advantage of seeds

protection, nourishment, and dispersal of embryo

Gymnosperm

“naked seed” plant with seeds exposed on cones or scales

Angiosperm

flowering plant with seeds enclosed in a fruit

Gymnosperm life cycle

sporophyte dominant with reduced gametophyte

Heterosporous

produces two types of spores (microspores and megaspores)

Microspore

develops into male gametophyte (pollen grain)

Megaspore

develops into female gametophyte within ovule

Ovule

structure containing the female gametophyte and egg

Micropyle

opening in ovule where pollen enters

Pollination

transfer of pollen to ovule

Fertilization in gymnosperms

sperm reaches egg via pollen tube or swimming (cycads and ginkgo)

Zygote

fertilized egg that develops into embryo

Embryo

young sporophyte within the seed

Gymnosperm cones

reproductive structures containing sporangia

Male cone

produces microspores (pollen)

Female cone

produces megaspores and contains ovules

Phyla of gymnosperms

Cycadophyta, Ginkgophyta, Coniferophyta, Gnetophyta

Example Gymnosperm 1

Ginkgo biloba

Example Gymnosperm 2

Pinus longaeva

Example Gymnosperm 3

Sequoia sempervirens

Mycorrhiza

symbiotic association between fungal and plant roots

Coralloid roots

specialized roots in cycads with nitrogen-fixing bacteria

Angiosperms

flowering plants with enclosed seeds and fruit formation

Flower

reproductive structure of angiosperms

Function of flower

enables fertilization and seed development

Four flower parts

sepals, petals, stamens, carpels

Sepals

protect developing flower bud

Petals

attract pollinators

Stamens

male reproductive structures producing pollen

Carpels

female reproductive structures containing ovules

Anther

structure that produces pollen

Ovary

structure enclosing ovules

Ovule

develops into seed after fertilization

Fruit

mature ovary that aids in seed dispersal

Double fertilization

one sperm fertilizes egg forming zygote, another forms endosperm

Endosperm

nutrient-rich tissue that nourishes developing embryo

Pollination in angiosperms

often involves animals such as insects

Advantage of pollination

increases genetic diversity

Inflorescence

cluster or arrangement of flowers on a plant

Monocots

plants with one cotyledon

Dicots

plants with two cotyledons

Monocot characteristics

scattered vascular bundles and parallel leaf veins

Dicot characteristics

vascular bundles arranged in a ring and branching veins

Vascular tissue

transport system including xylem and phloem

Xylem

transports water and minerals

Phloem

transports sugars

Adaptation of angiosperms

flowers and fruits enhance reproduction and dispersal

Success of angiosperms

diversity, pollination strategies, and efficient reproduction