exam 3 goat

Charophytes

Green algae; closest living relatives of land plants

Rings of cellulose-synthesizing proteins

Structures in charophytes and plants that produce cellulose for cell walls and define the shape of their cells

Flagellated sperm

Sperm characterized by their whip-like tails that enable them to swim through water, found in some plants and green algae

Phragmoplast

A group of microtubules that forms during cell division, aiding in the formation of a new cell wall

Sporopollenin

Durable polymer that prevents zygotes and spores from drying out

Alternation of generations

Life cycle in which plants alternated between multicellular haploid (gametophyte) and diploid (sporophyte) stages

Gametophyte

Haploid plant stage that produces gametes (sperm and eggs) by mitosis

Sporophyte

Diploid plant stage that produces spores by meiosis

Multicellular, dependent embryo

Embryo that develops within and is nourished by the tissue of the female gametophyte

Walled spores

Protective plant spores with walls containing sporopollenin, produced in sporangia

Sporangia

Organs in which meiosis occurs and spores are produced

Gametangia

Multicellular organs that produce gametes

Archegonia

Female gametangia that produce eggs

Antheridia

Male gametangia that produce sperm

Apical meristem

Region of dividing cells at the tip of roots and shoots, allowing growth in length

Cuticle

Waxy protective layer covering plant surfaces that prevent water loss

Stomata

Microscopic pores in leaves that allow gas exchange (CO2 in, O2 out)

Bryophytes

Nonvascular plants, including mosses liverworts, and hornworts

Liverworts (Phylum Hepatophyta)

Bryophytes that can be thalloid or leafy

Hornworts (Phylum Anthocerophyta)

Bryophytes whose sporophyte consists mainly of a sporangium without a seta

Mosses (Phylum Bryophyta)

Bryophytes with visible, elongated sporophytes

Bryophyte gametophyte

Dominant, photosynthetic generation that supports the dependent sporophyte

Bryophyte sporophyte

Dependent generation consisting of foot, seta, and capsule that produces spores

Foot (in bryophyte sporophyte)

Absorbs nutrients from the gametophyte

Seta

Stalk that elevates the capsule for spore dispersal

Capsule (sporangium)

Structure that produces and releases spores

Sphagnum (peat moss)

Type of moss that forms peat; important for fuel, soil conditioning, and carbon storage

Vascular tissue

Plant tissue specialized for transporting materials throughout the plant (xylem and phloem)

Xylem

Conducts water and minerals from roots to shoots; composed of dead cells

Phloem

Transports sugars and other organic compounds; composed of living cells

Roots

Organs that anchor plants and absorb water and nutrients from the soil

Leaves

Main photosynthetic organs of vascular plants

Microphylls

Small leaves with a single unbranched vein (found in lycophytes)

Megaphylls

Large leaves with a highly branched vascular systemS

Sporophylls

Modified leaves that bear sporangia

Homosporous

Produces one type of spore that develops into a bisexual gametophyte

Heterosporous

Produces two types of spores: microspores (male) and megaspores (female)

Lycophytes (Phylum Lycophyta)

Club mosses, spike mosses, and quillworts; seedless vascular plants with microphyll leaves

Monilophytes (Phylum Monilophyta)

Ferns, horsetails, and whisk ferns; seedless vascular plants with megaphyll leaves

Dominant sporophyte

Characteristic of vascular plants; sporophyte generation is larger and longer-living

Carboniferous forests

Ancient forests of seedless vascular plants whose remains formed today’s coal deposits

Seed

Plant embryo and its food supply, enclosed within a protective coat

Pollen grain

Structure containing the male gametophyte, enclosed in a protective pollen wall

Key adaptations for land

Seeds and pollen; allow plants to reproduce without standing water

Five derived traits of seed plants

Reduced gametophytes, heterospory, ovules, pollen, and seeds

Reduced gametophyte

Microscopic male and female gametophytes that are protected and nourished by sporophyte tissue

Advantage of reduced gametophyte

Protection from environmental stress and nutrient support from the sporophyte

Heterospory

Production of two types of spores: megaspores (female) and microspores (male)

Megasporophyll

Leaflike structure bearing megasporangia that produce megaspores

Microsporophyll

Leaflike structure bearing microsporangia that produce microspores

Megasporangium

Tissues that produces megaspores (female spores)

Microsporangium

Tissues that produces microspores (male spores)

Ovule

Structure consisting of a megasporangium, megaspore, and one or more protective integuments

Integument

Protective layer that surrounds the megasporangium; becomes the seed coat

Evolutionary advantage of seeds

Seeds survive better than spores and can be dispersed long distances

Gymnosperm

“Naked seed” plant; seeds not enclosed in fruit, usually produced on cones

Cone (strobilus)

Cluster of sporophylls where gymnosperm seeds form

Gymnosperm sporophyte

Dominant generation (e.g., pine tree) that produces male and female cones

Gymnosperm life cycle

Sporophyte produces spores in cones → gametophytes form → fertilization → seed development

Phylum Cycadophyta

Gymnosperm group with palm-like leaves and large cones

Phylum Ginkgophyta

Gymnosperm group with one extant species (Ginkgo biloba), fan-shaped leaves

Phylum Gnetophyta

Gymnosperm group including Ephedra and Welwitschia species

Phylum Coniferophyta

Largest gymnosperm phylum; includes pines, firs, redwoods

Flower

Specialized shoot with four floral organs: sepals, petals, stamens, and carpels

Sepals

Enclose and protect the flower bud before it opens

Petals

Attract pollinators with color or scent

Stamens

Male reproductive organs composed of anther and filament

Anther

Produces pollen grains (male gametophytes)

Filament

Stalk supporting the anther

Carpels (pistils)

Female reproductive organs: stigma, style, and ovary

Stigma

Sticky top of carpel that captures pollen

Style

Tube leading from stigma to ovary

Ovary

Contains ovules and becomes the fruit after fertilization

Flower symmetry

Can be radial (regular) or bilateral (irregular) depending on petal arrangement

Fruit

Mature ovary that protects seeds and aids in their dispersal

Double fertilization

In angiosperms, one sperm fertilizes the egg (2n zygote) and another fuses with two nuclei to form the triploid endosperm (3n)

Endosperm

Triploid tissue that nourishes the developing embryo in angiosperm seeds

Angiosperm life cycle

Includes double fertilization, development of seed and fruit, and alternation of generations

Basal angiosperms

Earliest-diverging angiosperm lineages (e.g., Amborella, water lilies, star anise)

Magnoliids

Angiosperms including magnolias, laurels, and black pepper plants

Monocots

Angiosperms with one cotyledon (seed leaf); includes grasses, orchids, palms

Eudicots

Angiosperms with two cotyledons; includes legumes, roses, and most trees

Monocot characteristics

One cotyledon, parallel leaf veins, scattered vascular bundles, fibrous roots, flower parts in 3s

Eudicot characteristics

Two cotyledons, netlike veins, vascular bundles in a ring, taproot system, flower parts in 4s or 5s

Products from seed plants

Food, wood, medicines, and secondary compounds like alkaloids

Secondary compounds

Chemical byproducts used in medicines, defense, and flavorings

Threats to plant diversity

Habitat destruction leading to extinction of many plant species

Three basic plant organs

Roots, stems, and leaves

Root

Organ that anchors a plant, absorbs water and minerals, and stores carbohydrates

Taproot system

One large main root with smaller lateral roots; typical of eudicots

Fibrous root system

Dense network of thin roots; typical of monocots

Root hairs

Tiny extensions of root epidermal cells that increase surface area for absorption

Root tip

Region where most water and mineral absorption occurs

Root adaptations

Modified roots with special functions (storage roots, aerial roots, prop roots, pneumatophores)

Stem

Plant organ consisting of nodes and internodes that support leaves and reproductive structures

Node

Point on a stem where leaves are attached

Internode

Stem segment between nodes

Apical bud (terminal bud)

Located at shoot tip; causes elongation of a young shoot

Axillary bud

Can form a lateral branch, thorn, or flower; located in the upper angle between leaf and stem

Modified stems

Stems adapted for functions such as storage, support, or reproduction (e.g., rhizomes, stolons, tubers)