biodiversity plants

What are Thallophytes?

Simplest form of a plant, aquatic, no specialized vascular system

What are Bryophytes?

Plants found in aquatic and land habitats with dominant gametophyte (haploid) stage; examples: mosses, liverworts, hornworts

What are Tracheophytes?

Vascular plants that grow vertically/tall with dominant sporophyte (diploid) stage; examples: ferns and pine trees

What are Angiosperms?

Seed-bearing plants with flowers and fruits, undergo double fertilization, most diverse land plants, non-flagellated male gametes

What happens during meiosis in the ovary of angiosperms?

Megasporocyte (2n) → four megaspores (n); one survives to form female gametophyte

What are synergid cells?

Two cells that flank the egg and guide pollen tube to the female gametophyte

What are antipodal cells?

Cells of unknown function in the female gametophyte

What happens during meiosis in the anther of angiosperms?

Microsporocytes (2n) → four microspores (n), each forms a pollen grain (male gametophyte)

What is inside the male gametophyte (pollen grain)?

Generative cell (forms 2 sperm) and tube cell (forms pollen tube)

What happens during double fertilization in angiosperms?

One sperm (n) fuses with egg (n) → zygote (2n); another sperm (n) fuses with polar nuclei → endosperm (3n)

What is the function of the seed coat?

Tough outer covering that protects the embryo/seed

What is the function of endosperm?

Primary storage tissue providing nutrients for embryo

What is the function of cotyledons?

Transfer nutrients from endosperm to embryo

What is dermal tissue in plants?

Epidermal cells covering plant surfaces, secrete waxy cuticle, contain guard cells for gas exchange

What is ground tissue in plants?

Performs most metabolic functions

What is vascular tissue in plants?

Consists of xylem (water transport) and phloem (sugar transport)

What are tracheids?

Long, tapered xylem cells; water passes laterally through pits

What are vessel elements?

Short, wide xylem cells with perforations for efficient water transport

What are sieve-tube members?

Phloem cells that transport sugars throughout plant

What are the three main plant tissues?

Dermal, vascular, ground

What is the epidermis of leaves?

Protective layer with cuticle to reduce transpiration

What is palisade mesophyll?

Leaf cells with chloroplasts; primary site of photosynthesis

What is spongy mesophyll?

Leaf cells with air spaces that allow gas exchange

What are stomata?

Microscopic pores that allow gas exchange; regulate balance between photosynthesis and water loss

What is the role of guard cells?

Specialized epidermal cells controlling stomata opening/closing

What is primary plant growth?

Increase in plant length

What is secondary plant growth?

Increase in plant girth/thickness

What is phototropism?

Plant growth in response to light

What is gravitropism?

Plant growth in response to gravity

What is thigmotropism?

Plant growth in response to mechanical stimuli (touch)

What is photoperiodism?

Plant’s response to changes in day length (light vs dark)

What are short-day plants?

Plants that flower when daylight is less than half the day

What are long-day plants?

Plants that flower when daylight is more than half the day

What are auxins?

Plant hormones that influence light and gravity responses; promote cell elongation

What are gibberellins?

Plant hormones that promote flower and stem elongation

What are cytokinins?

Plant hormones that stimulate cytokinesis (cell division)

What is abscisic acid?

Plant hormone that inhibits growth and promotes seed dormancy

What is ethylene gas in plants?

Plant hormone that promotes fruit ripening, flower production, and leaf abscission

What is the difference between monocots and dicots?

Monocots: 1 cotyledon, parallel veins, scattered vascular bundles, fibrous roots, flower parts in 3s; Dicots: 2 cotyledons, net-like veins, ringed vascular bundles, taproot, flower parts in 4s/5s

Give examples of monocots.

Lilies, Kentucky bluegrass

Give examples of dicots.

Oak trees

What are vascular bundles?

Groups of xylem and phloem, surrounded by bundle sheath cells

What is the epicotyl?

Part of embryo that develops into shoot tip (above cotyledons)

What is the hypocotyl?

Part of embryo that develops into stem below cotyledons

What is the radicle?

Embryonic root

What is the cotyledon?

Seed leaf that stores/transfers nutrients to embryo

What is a pro-tip comparison between angiosperm seeds and animal systems?

Angiosperm seeds are equivalent to fertilized animal eggs