EXAM 2 - Unit 11: Plant diversity

be able to identify the features of bryophytes

• have life cycles dominated by a larger haploid gametophyte

• live in moist environments, growing low to the ground, have no vascular tissue to transport water, and are dependent upon motile sperm for reproduction

• lack true leaves

• have small pores called stomata that allow CO2 uptake

be able to identify features of lycophytes

• similar to mosses and ferns, small vascularized

• they have microphyll leaves that arise from rhizome

• microphylls have a single, unbranched vein

• suggests that modern leaves may have arisen from simple extension of the stem

be able to identify features of ferns

• vascular but seedless

• xylem is lignified, the walls of the individual tracheid cells made up of a woody-like polysaccharide, lignin, similar to cellulose

• the xylem cells are dead at maturity, and carry water and minerals upward

• water molecules are hydrogen bonded together so they stick together, however if they break the bonds, they can bond to the side wall of the xylem

be able to identify features of gymnosperms

• cycads, pine trees, fit trees, etc

• the sporangia are found on cones

• pine trees have 2 different kinds of cones:

  • pollen or staminate cones, which give rise to sperm-producing gametophytes

  • and ovulate, or seed or egg cones, which give rise to egg producing gametophytes

be able to identify features of angiosperms

• the “shells” or “vessel” “seeds” (angio, sperm)

• the flowering plants, the fruiting plants

• often, confine male and female reproductive organs in close proximity to each other

• most numerous and successful of multicellular life forms

be able to identify the structure and function of antheridia

structure:

• small sacs on the “leaf” edges (little flowers)

function:

• produces sperm cells

be able to identify the structure and function of archegonia

structure:

• flask-shaped female (old seeds)

function:

• produces female gametes, eggs (non-motile)

be able to label parts of a leaf

stipule: small leaf-like appendages at the base of the lead stalk or “petiole”

• photosynthetic and may protect the keaf with spines or sticky secretions

petiole: attaches blade to stem but can twist to alter blade oreintation to sun or wind

blade: flat, laminate structure providing surface area for photon absorption, CO2 uptake, and water and O2 release

base: attaches blade to petiole

margin: the perimeter edge of a leaf

apex: the tip of the leaf, acts as a diminished surface allowing for water to run off

be able to identify the structure and function of leaves

structure:

• outer protective laters (epidermis and cuticle), the inner tissues (mesophyll) where photosynthesis occurs, and a network of vascular veins (xylem and phloem) for transport

function:

• photosynthesis, gas exchange, transpiration

be able to identify the structure and function of gemma cups

structure:

• cup-shaped structures found on some bryophytes, like liverworts and some mosses

• the cups are filled with small, green, disc-like gemmae and the cups protect the gemmae and faciliate their dispersal, often through the splash-cup mechanisms where rain droplets dislodge and carry them away from the parent plant

function:

• asexual reproduction

be able to identify the structure and function of gemmae

structure:

• small, green disc-shaped structures located inside the gemma cups

function:

• asexual buds that, when dispersed by water, can grow into a new, geetically identical plant

be able to identify the structure and function of lignin

structure:

• woody-like polysaccharide, similar to cellulose

function:

• enhances plant cell wall rigidity

be able to identify the structure and function of microphylls

microphyll: the gap in the ovularian integument

structure:

• small leaf with a single, unbranched vein with no leaf gap

function:

• performs photosynthesis in simple, low-growing plants like lycophytes

be able to identify the structure and function of megaphylls

structure:

• a large complex leaf with a system of multiple, branching veins, which makes megaphylls have a large complex vascular system, which allows for efficient transport of water, nutrients, and sugars for photosynthesis

function:

• their large size and branching structure produces a greater surface area for photosynthesis, allowing the plant to capture more sunlight for greater energy production

be able to identify the structure and function of phloem

structure:

• composed of a column of individual cells called “sieve tube elements” (not vessel elements)

• connect to each other by sieve plates at each end

• companion cells facilitate the maintenance of the sieve elements and the loading and unloading of materials

  • aphids and other hemipterans will tap into the phloem layer with specialized mouthparts including a piercing “stylet”

function:

• transports water, sugar, and other molecules up and down the plants (and lateral)

be able to identify the structure and function of pinna

structure:

• a primary leaflet or segment that grows from the rachis

function:

• increases the plant’s surface area for photosynthesis

be able to identify the structure and function of rhizoid

structure:

• simple hair-like structures

function:

• functions as anchors and absorb water and nutrients for non-vascular plants like mosses, liverworts, and some algae (meaning they lack the specialized vascular tissues like xylem and phloem)

be able to identify the structure and function of rhizome

structure:

• branched underground

function:

• the stem of the fern and is often underground. even when it’s still above the ground it is called a rhizome

be able to identify the structure and function of roots

structure:

• at germination: the radicle (the first part of the plant to emerge) equipped with a tough, dense, compact root cap (or calyptra)

• centered in front of the meristem, the area where constant mitosis occurs, and the root is elongated

function:

• they anchor the plant, absorb water and nutrients, and can store food

be able to identify the structure and function of sori

structure:

• visible structures of sporangia on the underside of the fern leaves that produce, protect, and release spores facilitating fern reproduction

• helps protect the developing spores from environmental hazards like drying out

• the sporangia within the sori produce numerous haploid spores through meiosis during the ferns reproductive phase

• when the spores mature, the sorus releases the spores: the release is often triggered by environmental factors like wind and humidity

function:

• housing and releasing spores for reproduction

be able to identify the structure and function of spores

structure:

• haploid, single-celled reproductive units in plants that germinates to form a new organism, while the sporangium is the structure that produces them

• have thick, protective cell wall that prevents them from drying out and environmental damage

function:

• dispersal by wind or water to new locations, allowing for the spread of species

• their thick, protective walls allow spores to survive in harsh conditions and remain dormant until conditions become favorable for growth

• they are a key part of the plant life cycle as they develop into new organisms that eventually reproduces to continue the cycle

be able to identify the structure and function of sporophylls

structure:

• vary in appearance, from green, leaf-like structures in ferns to highly modified forms like the scales of a pinecone. they bear one or more sporangia, which are spore-producing sacs

• clustered tightly on a central stalk to form a cone or strobilus

• heterospory (heterosporous plants): two types of spores

  • microsporophyll: bear microsporangia, which produce small microspores that develop into male gametophytes

  • megasporophyll: bear megasporangia, which produce large megaspores that develop into female gametophytes

function:

• produce spores through meiosis and when mature release the spores for dispersal

be able to identify the structure and function of stem

vascular components of plants, in which food, water, and minerals flow

be able to identify the structure and function of stomata

• mimic pores in the epidermis of the leaf or stem allowing for the movement of CO2 in the plant and ester out

• thin fibrous “stems” or stalk for support

be able to identify the structure and function of strobilus

reproducing structure in plants like conifers and ferns, often referred to as cone, bears spores or seeds

• found in gymnosperms and some seedless vascular plants like some ferns

• main function is reproduction by producing spores or seeds

two types:

• male strobili (microstrobili): produce pollen (microspores) which develop into the male gametophyte

• female strobili (megastrobili): house ovules that contain the female gametophyte, and after fertilization, develop into seeds

be able to identify the structure and function of tracheids

structure:

• long and tapering cells that connect to each other by small “pits” in the side walls

function:

• transporting water and minerals and providing structural support to the plant

be able to identify the structure and function of vascular bundle

structure:

• are centered at the root for anchorage

• vascular cambium lies between the xylem and phloem and gives rise to each

  • the xylem and phloem tend to travel together in compact

  • spread out in stem for flexibility

function:

• transport and support

be able to identify the structure and function of waxy cuticle

waxy covering protects the plant tissues from desiccation

be able to identify the structure and function of xylem

function: transports water, minerals, hormones - one way (up, sorta), from roots to leaves

• composed of tracheids and/or vessel elements, individual cells in the xylem

define in writing dioecious

having male sperm producing reproductive parts on one body plan and the female egg-producing reproductive parts on another body plan

define in writing evapotranspiration

• the heat driven or wind driven movement of water from root to leaf

• the rest of the upward movement of water is created by evapotranspiration

• provides for mineral and hormonal flow, cooling water for photosynthesis

• water flows through xylem upward to the leaves, exiting largely via the stomata

define in writing monoecious

having male sperm producing and female egg-producing reproductive parts on the same body plan

define in writing spore

• a single-celled reproductive body produced by certain fungi, plants, or bacteria

• it doesn’t have to fuse with another cell in order to develop into a new individual

define in writing syngamy

the fusion of sperm and egg to produce a zygote

define in writing zygote

the cellular 2n fusion product of a sperm and egg

be able to identify the time period when plants began to colonize terrestrial environments

colonization of land, 500 mya

• plants and fungi

• challenges: drought, high-intensity light, UV radiation, osmotic pressure, pathogens

• changes in plants: transcriptional complexity, structure complexity, hormone signaling pathways, secondary metabolism

be able to describe in writing, using complete sentences, the life cycle of the Bryophytes

• the haploid spore germinates by mitosis into protonema, which develops into the leafy gametophyte anchored by rhizoids or a short rhizome

• on the gametophyte, male antheridia produce flagellated sperm and female archegonia contain a single egg

• during wet conditions, sperm swim to the egg and syngamy (fertilization) forms a diploid zygote

• the zygote develops by mitosis into an embryo, which remains attached to the gametophyte

• the embryo growns into the sporophyte, made of a seta, podium, and capsule (the sporangium)

• inside the capsule, meiosis produces haploid spores

• spores are released, and each can grow into a new gametophyte, continuing the cycle

• bryophytes reproduce with spores, not seeds