Biology 1002 Section 1: Introduction to the Plants

Charophytes

Plants evolved from green algae called ___________.

Phragmoplast

A cell structure that forms late in cytokinesis only in plants and certain charophytes.

Sporopollenin

A durable polymer that covers exposed zygotes of charophyte algae and forms the walls of plant spores, preventing them from drying out.

Embryophytes

Land plants, plants with embryos.

Alternation of generations

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

Morphological evidence

Evidence that different species are related by similar body shape and other structural features.

Molecular evidence

The universal genetic code and homologous molecules such as genes and proteins provide evidence of common descent.

Rings of cellulose-synthesizing proteins, structure of flagellated sperm, formation of a phragmoplast

The three distinctive traits that charophytes share with plants:

Spores

Produced by meiosis. Grow into haploid organisms by mitosis.

Sporangia

Multicellular organs that produce spores

Archegonia

Egg-producing female vascular plant organ

Antheridia

Sperm-producing male vascular plant organ

Apical meristem

Embryonic plant tissue in the tips of roots and in the buds of shoots that supplies cells for the plant to grow in length.

Cuticle

A waxy covering on the surface of stems and leaves that acts as an adaptation to prevent desiccation in terrestrial plants.

Stomata

A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant.

Mycorrhizae

Ecological relationship between the mycelium of a fungus and the roots of certain plants

hepatophyta, anthocerophyta, bryophyta

non vascular plant phyla (3)

lycophyta and monilophyta

2 phyla of seedless vascular plants

Ginkgophyta, Cycadophyta, Gnetophyta, Coniferophyta

phyla of gymnosperms (4)

vascular tissue

Plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plant body.

Clade

A group of species that includes an ancestral species and all its descendants.

gymnosperms and angiosperms

two clades of living seed plants

Gymnosperms

A plant that produces seeds that are exposed/naked rather than seeds enclosed in fruits

Angiosperms

A flowering plant which forms seeds inside a protective chamber called an ovary.

Ferns and other seedless vascular plants

What were the first plants to grow tall?

Xylem

Nonliving vascular tissue that carries water and dissolved minerals from the roots of a plant to its leaves

Phloem

Living vascular tissue that carries sugar and organic substances throughout a plant

Lignin

substance in vascular plants that makes cell walls rigid

Roots

Absorbs water and minerals from the ground. Anchors plant in ground.

Leaves

The main photosynthetic organs of vascular plants.

microphylls

In lycophytes, a small leaf with a single unbranched vein.

megaphylls

a leaf with a highly branched vascular system, characteristic of vast majority of vascular plants; Complex leaves

sori

clusters of sporangia

sporophylls

modified leaves with sporangia

strobili

cone-like structures formed from groups of sporophylls

homosporous

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

heterosporous

A term referring to a plant species that has two kinds of spores: microspores that develop into male gametophytes and megaspores that develop into female gametophytes.

Megaspores

develop into female gametophytes

microspores

develop into male gametophytes

Seed

plant embryo and a food supply encased in a protective covering

reduced gametophytes, heterospory, ovules, pollen

In addition to seeds, the following are common to all seed plants

Advantages of reduced gametophytes

- Can develop from spores retained within parent sporophyte; provides nutrients

- Protects gametophyte from UV radiation and drying out

Heterospory

the production of two distinct types of spores by different structures

ovule

A structure that develops within the ovary of a seed plant and contains the female gametophyte.

Integuments

Layers of sporophyte tissues that contribute to the structure of an ovule of a seed plant.

pollen grain

In seed plants, a structure consisting of the male gametophyte enclosed within a pollen wall.

Pollination

The transfer of pollen from male reproductive structures to female reproductive structures in plants

flowers and fruits

Angiosperms have two key adaptations which are:

Sepals

enclose the flower

Petals

modified leaves which are usually bright in color to attract pollinators.

Stamens

The pollen-producing male reproductive organ of a flower, consisting of an anther and filament.

Carpel

The female reproductive organ of a flower, consisting of the stigma, style, and ovary.

cross-pollination

a reproductive process in which pollen from one plant is transferred to the stigma of another plant

Fruit

A mature ovary of a flower that protects dormant seeds and aids in their dispersal.

Monocots

angiosperms that have only one seed leaf

Eudicots

Member of a clade consisting of the vast majority of flowering plants that have two embryonic seed leaves, or cotyledons.