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MASON / Biology / BIOL 310 / What are the characteristics of progymnosperms?

What are the characteristics of progymnosperms?

What are the characteristics of progymnosperms?


School: George Mason University
Department: Biology
Course: Biodiversity
Professor: Geoffrey birchard
Term: Summer 2015
Tags: gmu, george mason university, Biodiversity, and Biology
Cost: 50
Name: BIOL 310 - Study Guide 2 - Chapters 28 and 29
Description: A quick study guide for chapters 28 and 29. I followed the textbook "LIFE: The Science of Biology", 10th edition. Good luck on the second exam, everyone!
Uploaded: 03/08/2017
9 Pages 32 Views 9 Unlocks

Chapter 28: Plant without Seeds: From Water to Land 

What are the characteristics of progymnosperms?


(It will make following this study guide much easier)

Plantae​ - primary endosymbiosis is a synapomorphy

● Algae​ - aquatic photosynthetic eukaryotes


● Sister group to rest of Plantae

● Chloroplast contains little bit of peptidoglycan between inner and outer membrane ○ Peptidoglycan is not found in other photosynthetic eukaryotes

Red Algae

● Almost all multicellular

● Chloroplasts contain:

○ Phycoerythrin​ - the photosynthetic pigments which gives it a red color ○ Chlorophyll a (green)

○ Phycocyanin

What are the main groups of gymnosperms?

○ Carotenoids

● Color of algae depends on intensity of light

○ More light - algae appear green

○ In deep waters - algae appear red

● Grow in both shallow and deep waters

● Some found in fresh water

● Most are attached to a substrate (by holdfast)

Green Plants If you want to learn more check out What were the main points of thomas paine's common sense?

● Contain chlorophyll a and b

● Store photosynthetic products as starch in chloroplasts

● Chlorophytes

○ “Most” green algae

○ Most aquatic (but some are marine, and more in fresh water)

○ Some terrestrial (live in moist area)

○ Size ranges from microscopic unicellular to large multicellular

What is monocot?

○ Ex. Volvox

■ Colonial, unicellular

■ Colonies specialized for reproduction, not for specific organs or tissues Streptophytes If you want to learn more check out What does the short-run aggregate supply curve show?

● Includes all other green algae (apart from chlorophytes) and land plants ● Closest relatives of land plants (are aquatic green algae)

○ Coleochaetophytes ​and Stoneworts

■ Multicellular

■ Eggs found in parental organism

■ Adjacent cells connected through plasmodesmata

■ Similarities in mitosis and cytokinesis

■ Stoneworts​ are sister group of land plants

● Branching and apical

Land Plants (embryophytes)

● Embryo surrounded by parental tissue

● Nonvascular land plants ​(lack tracheids - refer below)

○ Liverworts

○ Mosses

○ Hornworts

● Vascular plants (tracheophytes)

○ The other clades

○ Have vascular systems that transport material throughout plants

○ Contain tracheids​ (fluid-conducting cells)

Plants Colonize Land If you want to learn more check out What are the stages of social evolution by lewis henry morgan?

● First appeared 450 to 500 million years ago

● Adaptations that helped plant survival on land:

○ Cuticle (waxy covering that prevents water loss)

○ Stomata (openings in leaves that allow for gas exchange and water loss) ○ Gametangia (multicellular and enclose gametes so they won’t dry out) ○ Embryos (young plants protected by parental tissue)

○ Pigments (protection from UV radiation)

○ Spore walls (protects sports for desiccation and decay)

○ Mutual benefits with fungi (allows for uptake of nutrients from soil)

Life Cycle

● Alternation of generations

○ Mitosis - Gametophyte produces gametes (n)

○ Gametes fuse during fertilization to form zygote (2n)

○ Mitosis - zygote forms in sporophyte (multicellular, 2n)

■ Sporangia​ are specialized reproductive organs in the sporophyte

○ Meiosis sporophyte produces spores ​(n)

○ Mitosis - spores germinate and develop into a multicellular haploid (gametophyte) Non-Vascular Plants

● Grow in dense mats, usually in moist habitats

● Short because they do not have an efficient vascular system Don't forget about the age old question of Who are the former cold war rivals?

● Lack true leaves, stems, and roots

● Have leaf-like structures that hold onto water when it splashes into them ● Water moves by capillary action

● Minerals distributed by diffusion

● Material tissue protect embryos

● Some have a cuticles

● Can grow on soil, vascular plants, rocks, dead and fallen trees, and buildings ● None live in oceans

● Life Cycle:

○ Haploid gametophyte contain chloroplasts

○ Gametes form into sex organs called gametangia

■ Archegonium​ (2n) female sex organ - single egg

■ Antheridium ​- male sex organ - sperm with two flagella

○ Sporophytes depend on gametophyte


● Most have leafy gametophytes, some have thalloid gametophytes

● Liverwort sporophytes shorter than those of mosses and hornworts

○ Has a stalk

● Ex. Marchantia

○ Asexual reproduction by fragmentation

○ Asexual reproduction by gemmae cups (gemmae dispersed by raindrops)


● Found on damp, cool ground

● Have stomata

○ Stomata is synapomorphy for mosses and all other land plants (but liverworts) ● Spore germination Don't forget about the age old question of What is the anti-war movement in world war 1?

○ Branched, filament known as protonema

■ Unique to mosses

■ Some contain chloroplasts

■ Some contain rhizoids

● Anchor protonema to substratum

● Mosses too large for water to transport through diffusion

○ Contain a cell called hydroid

■ When it dies, it forms channel for water to travel through

● Ex. Sphagnum

○ Partially decomposed plant matter is called peta Don't forget about the age old question of What is retrieval?


● Single, large platelike chloroplast

● Capable of growing without a limit

○ Stop growing due to lack of a transport system

● No stalk

● Internal cavities filled with mucilage

○ Often contain cyanobacteria

Land Plant Diversification

● Key synapomorphies is developed vascular tissue

○ Xylem

■ Water and minerals from soil

■ Contain lignin

● Structural support against gravity

○ Phloem

■ Products of photosynthesis

○ Tracheids

■ It evolved about 430 mya

■ Principal water-conducting element of xylem

● All vascular plants except angiosperms and gnetophytes

■ Provided pathway for transport of water and minerals\

■ Contained lignin

● Upward growth

● Branching, independent sporophyte

○ Produces more spores

○ Sporophyte independent of gametophyte

● Initial lack of herbivores on land allowed plants to grow

○ 425 mya vascular plants served as fossils

○ Allowed for arthropods, vertebrates, and animals to move onto land

○ Plant material from forests sank to bottom covered layers of sediment, and through pressure and high temperatures transformed into coal

Different Groups:

● Rhyniophytes

○ Closest relatives to living vascular plants

○ No roots

○ Anchored to soil by horizontal stems called rhizomes

■ Contained unicellular filaments called rhizoids​ (water-absorbing)

○ Aerial branches and sporangia found at tips of branches

■ Sporangia similar to those of mosses

■ Branching pattern is dichotomous

● Apex produced two equivalent new branches

○ Pair of branches diverged at same angle

● Lycophytes

○ Club mosses, spike mosses, and quillworts

○ Relatively few species

○ True roots that branch dichotomously

○ Leaflike structures called microphylls

■ Arranged spirally on stem

○ Growth from apical cell division

○ Sporangia (of club mosses) in conelike structures called strobili

■ Spore-bearing microphylls

■ Some do not have strobili and bear sporangia on upper surface of microphylls ● Monilophytes​ (clade)

○ Contains horsetails (only 15 species, all genus Equisetum) and ferns

○ Main stem and side branches are differentiated

○ Horsetails 

■ Reduced true leaves

● Form into distinct circles around the stem

■ Sometimes called “scouring rushes”

● Rough silica deposits found in cell walls

■ Have true roots (branch irregularly)

■ Large sporophyte and small gametophyte

○ Ferns 

■ First appeared in Devonian period

■ More than 12,000 species

■ Most terrestrial, some in shallow fresh water

● Terrestrial

○ Large leaves with branches vascular strands

■ Require liquid water for male gametes to reach female gametes

■ Sporangia of ferns develop on stalks in clusters (sori​)

● Found on undersurface of leaves

● Euphyllophytes ​(clade)

○ Contains monilophytes and seed plants

○ Synapomorphy - overtopping​ (one branch grows beyond the other)

■ Allows for plant to shade dichotomously branching competitors

■ Allowed for development of new leaf-like structure

● Megaphyll

○ First appeared in Devonian period

○ Large megaphylls more common in Carboniferous period

■ Evolved due to drop in CO2 concentration

Homospory and Heterospory

● Homosporous

○ Single type of spore

■ Develop into a single type of gametophyte that contains both female and male sex organs

● Heterosporous

○ Two distinct types of spores

■ Megaspore ​(formed in small numbers in megasporangia​)

● Develops into female gametophyte (megagametophyte​)

● Produces eggs

■ Microspore ​(formed in large numbers in microsporangia​)

● Developes into male gametophyte (microgametophyte​)

● Produces sperm

Chapter 29: Evolution of Seed Plants 


● First seedless vascular plant to have a thickened woody stem

● All species are now extinct


● Protection for embryo until conditions are right for germination

● Earliest fossil evidence - Devonian rocks

● Seed ferns

○ Now extinct

○ Contained woody stem

○ Has fern-like foliage with seeds attached to the leaves

● Today’s seed plants are:

○ Gymnosperms​ (pines and cycads)

■ Few groups have swimming sperm, but sperm is transferred through pollen so there is no need for liquid water (modern cycads and ginkgos)

○ Angiosperms ​(flowering)

Seed Plants

● Heterosporous

○ Microspore develops into multicellular male gametophyte - pollen grains

■ Spore wall around pollen grain contains sporopollenin (protects pollen grain from desiccation and chemical damage)

○ Megaspores depend on sporophyte for food & water

○ Megasporangium surrounded by integument ​(protects megasporangium)

■ Megasporangium + integument = ovule ​(develops into seed after fertilization) ● Pollination

○ Arrival of pollen grain close to female gametophyte

○ Pollen grain produces pollen tube

○ End product - multicellular seed

■ Seed has three generations of tissue

● 1st generation: seed coat developed from integument

● 2nd generation: Haploid tissue from female gametophyte provides


● 3rd generation: at center, new diploid sporophyte

Secondary Growth

● Increases diameter of stems and roots

○ Secondary xylem and phloem produced

● Provides water transport

● Older wood clogged with resin - provides structural support

● Allows for more growth


● Groups:

● Cycads

○ Palm-like

○ Earliest diverging clade

○ 300 species (grow as tall as 20 meters)

○ It’s tissues are highly toxic to humans (when ingested)

● Ginkgos

○ Common in Mesozoic era

○ Ex. Ginkgo biloba ​(maidenhair tree)

■ There are male and female trees

■ Have distinguished X and Y chromosomes

● Gnetophytes

○ Ex. Welwitschia

■ Desert plant

■ Strap-like leaves

● Conifers

○ Most abundant

○ 700 species

○ cone-bearing (pines and redwoods)

■ California redwoods tallest known trees (over 100m)

■ Male and female cones​ contain reproductive structures

● Female (seed bearing) called megastrobilus

● Male (pollen grains) called microstrobilus

○ IMAGE 29.8 on page 595 describes life cycle 

● Except for gnetophytes, (living) gymnosperms only have tracheids within xylem ● Lack vessel elements and fibers

● Dominated during Mesozoic era


● Flower​ - sexual structure

○ Single or grouped together (inflorescence​)

○ Stamen​ - bear microsporangia

■ Composed of a filament​ bearing an anther​ (contains pollen producing microsporangia)

○ Carpels​ bear megasporangia

■ One or more fused carpels is a pistil

● Swollen base of pistil contains one or more ovules called an ovary

● Apical stalk is the style

● Terminal surface is stigma​ (receives pollen grains)

○ Specialized sterile leaves

■ Inner are petals a​ nd outer are sepals

○ Calyx​ and corolla​ attract pollinators

○ A flower with both functional mega- and micro- sporangia is called perfect ○ A flower with nonfunctional stamens or carpels is called imperfect

○ Monoecious

■ Micro- and mega- sporangiate occur on same plant

■ Ex. corn or birch

○ Dioecious

■ Produces either flowers with stamens or flowers with carpals

■ Ex. willows and date palms

● Fruit​ (synapomorphy of angiosperms) - protects seeds and promotes dispersal ○ Not always fleshy, can be hard and woody

○ Simple fruit

■ Develops from single carpel or fused carpel

■ Ex. plum and peach

○ Aggregate fruit

■ Develops from several separate carpels

■ Ex. raspberries

○ Multiple fruits

■ Develops from cluster of flowers

■ Ex. pineapples and figs

○ Accessory fruits

■ Developed from parts in addition to carpels and seeds

■ Ex. apples, pears, and strawberries

● Angiosperm synapomorphies

○ Ovules and seeds enclosed in a carpel

■ Prevents self-pollination

○ Reduced female gametophytes

○ Vessel elements​ - specialized water-transporting cells

○ Fiber ​- supports plant body

○ Phloem with companion cells

○ Double fertilization

○ endosperm

Changes in flower structure

1. Fixed number of floral organs

2. Petals and sepals differentiated

3. Symmetry from radial to bilateral

Bush Monkeyflower (Mimulus aurantiacus)

● Pollinated by hummingbirds

○ Stigma serves as a screen (hides anthers)

○ When hummingbird touches stigma, two lobes of stigma retract so humminbird picks up pollen from anthers

○ Helps to decrease chances of self-pollination

Flowers of Yucca Species

● Pollinated by only one species of yucca moth

● Moth can only pollinate one species of yucca

● This relationship provides the plant a reliable mechanism to pollinate its own species Bird-pollinator species

● Often red and odorless

Insect-pollinator species

● Have characteristic odors

Bee-pollinator species

● Have nectar guides (flower markings)


1. Pollination

a. Microgametophyte onto stigma

2. Growth of pollen tube

3. Double Fertilization

a. Two male gametes participate

i. One gamete combines with egg - develops diploid zygote

1. Zygote develops into embryo

a. Has embryonic axis

i. Becomes stem and root and one/two cotyledons​ (“seed


1. Cotyledon can ask as absorptive organs which

digest endosperm

2. In some they are photosynthetic

3. Often both roles

ii. Second gamete combines with two other haploid nuclei - forms triploid nucleus 1. Gives rise to endosperm


● Single embryonic cotyledon

● Ex. grasses, cattails, lilies, orchids, and palms


● Two embryonic cotyledon

● Ex. most herbs (non-woody plants), trees, shrubs, and vines

● Ex. oaks, willows, roses, sunflowers, and snapdragons


● Sister group to monocots and eudicots

● Ex. avocados, cinnamon, magnolias, and black pepper

Amborella ​(genus)

● Sister group to remaining flowering plants

● Woody shrub

● Lives only in New Caledonia

● 5 to 8 carpel in spiral arrangement

● 30 to 100 stamen

● Xylem lacks vessel elements

Use of plants for medicine

● Taxol

○ Anticancer drug

○ 1962 - Tested extracts from bark of Pacific yew (Taxus brevifolia)

■ Showed anti-tumor activity against rodent tumors

○ 1971 - Taxol was isolated

○ 1977 - Tested against human cancer

○ 1993 - FDA approved for human use

● Ethnobotanist

○ Study how plants are used by people in their local environment

○ Quinine discovered as treatment for malaria

■ Bark of local Cinchona tree used to treat fever

● Bark was used to treat malaria

○ 1820

■ Identified quinine as active ingredient

Use as food source

● Human cultivated angiosperms to provide reliable food supply

● Ex. corn, rice, coconut, wheat, potato, sweet potato, cassava, sugar cane, sugar beet, soybean, common bean, etc.

● Half of human population depends on Oryza sativa (rice)

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