Chapter 24 seedless plants

Aquatic Plants

No threat of desiccation, structure support, uv protection, gametes sent through water

First terrestrial plants

lived in humid environments, stayed small, developed uv protection and tolerance to desiccation.

First plants adaptations

1. sporopollenin

2. alternation of life cycle (sporophyte and gametophyte)

3. Apical meristem

4. waxy cuticle

5. Lignin

Sporopollenin

Spores are surrounded by cell walls made of sporopollenin which protect the spore from desiccation/degradation

Alternation of generations

Life cycle of organisms that have a multicellular diploid and haploid stages.

seedless plant life cycle

1. haploid gametophyte stage produce haploid gametes through mitosis

2. sperm and egg from 2 plants fertilize to produce diploid zygote

3. zygote develops to form diploid sporophyte

4. sporophyte creates haploid spores through meiosis to create new plant

sporophyte stage

Creates a sporangia(sporangium) structure made of sporocytes that produce spores which disperse to create a new plant.

Monoecious

Plant that has both male and female parts

Homosporous

Sporophytes that produce only 1 type of spore. germinating plant will usually be monoecious.

Heterosporous

Plant that produces 2 types of spores, a male microspore and a female megaspore.

Gametophyte stage

haploid stage in plants that produces gametes through mitosis. create a male gametangium called the antheridium which release sperm into watery enviroment to reach female archegonium which produces eggs.

Apical Meristem

comprised of undifferentiated cells that can develop into any cell. located in the shoot tip and root tip which allows for vertical up and downward growth.

Waxy cuticle

Epidermal tissue that contains wax. protects leaves and stem via covering and prevents water loss.

Bryophytes

Nonvascular seedless plants with a dominant gametophyte stage and dependent sporophyte stage. consists of mosses, liverworts, and hornworts.

Bryophyte structure

No conductive tissue. have thallus and rhizoids. no true leaves/stems/roots. very small.

Bryophyte lifecycle

Dominant gametophyte with dependent sporophyte. gametangia develop from thallous. antheridium produces sperm and archegonia produces eggs. sperm fertilizes eggs to produce zygote. zygote grows in archegonia which then grows into sporanangia and begins producing spores through meiosis

Vascular seedless plants

has xylem and phloem (conductive vascular tissue) Dominant sporophyte stage. have roots. still water dependent

Vascular seedless plants lifecycle

Spororphyte stage is dominant. sporophyte grows from parent plant but is independent on it. sporangium produces haploid spores through meiosis. spores germinate into gametophyte(haploid). gametophyte creates male antheridium and female archegonium. they produce gametes via mitosis. they then fertilize and create a zygote.