chapter 25 - seedless plants

more light, more CO2 and minerals, less competition/herbivory

what are the advantages of plants moving to land?

desiccation, no water support, harder reproduction

what are the disadvantages of moving to land?

desiccation

when plants dry out due to the evaporation of water

waxy cuticle

prevents water loss by forming a waterproof layer on plant

secondary compounds

chemical compounds produced by plants strictly for repelling or attracting predators or pollinators (defense mechanism)

mycorrhizae

ecological relationship between the mycelium of a fungus and the roots of certain plants -> helps plants absorb nutrients

apical meristems

localized regions of cell division at the tips of roots and shoots that facilitate growth

sporopollenin

walled spores that facilitate dispersal

gametangia

a reproductive organ that houses and protects the gametes of a plant

alternation of generations

the alternation between the haploid gametophyte and the diploid sporophyte in a plant's life cycle

bryophytes

non-woody, small, ground-covering plants that requires water for reproduction

- gametophyte dominant

- no vascular tissue

- have rhizoids

- grow w/in archegonium of gametophyte and sporangium makes many haploid spores

rhizoids

a thin, rootlike structure that anchors a moss and absorbs water and nutrients

liverworts

aka "marchantiophyta"

- a type of bryophyte

- flat (thalloid) or leafy miniature trees

- simple or very small sporophytes

hornworts

aka "anthocerotophyta"

- a type of bryophyte

- long horn-shaped sporophyte

- good colonizers of moist soils

- symbiotic relationship w/ nitrogen fixing cyanobacteria

moss

aka "bryophyta"

- most common type of bryophytes

- sporophyte grows up from female gametophyte to gain elevation for spore dispersal

- major primary producers in cold or high altitude regions

- fertilization occurs for this group when the flagellated sperm enters the archegonium

moss life cycle

- a sporophyte has a specialized capsule that holds the spores which grow into separate male and female gametophytes.

- antheridia produce sperm on the male gametophytes and the archegonia produce eggs on the female gametophyte

- antheridium fertilizes the egg of the archegonia which grows into a new sporophyte

seedless vascular plants

plants that have vascular tissue but reproduce by spores

- sporophyte dominant

- rely on vascular tissue to transport water and nutrients

xylem

vascular tissue that carries water upward from the roots to every part of a plant

phloem

vascular tissue in plants that conducts sugars and other metabolic products downward from the leaves

microphyll leaves

small, spine-shaped leaves supported by a SINGLE strand of vascular tissue

- only lycophytes have these

megaphyll leaves

leaves w/ highly branched vascular system

- have greater photosynthetic productivity

- all other vascular plants have these kind of leaves

sporophyll leaves

modified leaves that bear sporangia which produce haploid cells via meiosis

- in ferns these are called sori and generate spores on the underside of leaf

- in lycophytes these are called strobilus and appear in a cone like structure

homosporous

referring to a plant species that has a single kind of spore, which typically develops into a bisexual gametophyte

heterosporous

referring to a plant species that has two kinds of spores: microspores (male gametophytes) and megaspores (female gametophytes)

lycophytes

small microphylls that live in tropical and temperature areas

- a type of seedless vascular plants

- encompasses club mosses, spike mosses, and quillworts

- club mosses are homosporous while quillworts and spike mosses are heterosporous

monilophytes

group that includes ferns, horsetails, and whisk ferns and their relatives

- a type of seedless vascular plants

whisk ferns

aka "psilophyta"

- a type of monilophyta

- homosporous plants w/o true leaves or roots

- dichotomous branching

- photosynthesis occurs in the stem

horsetails

aka "equisetum"

- a type of monilophyta

- homosporous plants w/ joined stems and tiny leaves

- have strobili

- photosynthesis occurs in the stem

ferns

aka "pterophyta"

- most widespread and diverse monilophyta

- homosporous w/ large megaphylls

- sori on underside of sporophylls

- mostly in understory or as epiphytes

epiphytes

plants that grow on the surface of other plants

fern life cycle

1) zygote develops into leafy adult plant

2) spores are released from spore cases and grow into tiny, heart-shaped gametophytes. each gametophyte has both male and female structures.

3) sperm swim to another gametophyte to fertilize eggs