Botany Exam 3
Which of these is NOT a part of a gametic life cycle?
Alternation of generations
Coevolution can be defined as;
An alliance between species that influence the evolution of each other.
Plant-animal coevolution strategies are important to humans too
An apple orchard needs pollinating agents for better yield A squash garden needs pollinators to carry pollen from male to female flowers
Where are female gametophyte eggs produced?
Archegonia (n)
Where do you find integument? What does integument become at later stages?
Around the megasporangium in the ovule of all seed plants, later becomes the seed coat
Your friend brags to you about his fearless adventures in the Alaskan wilderness where he was once lost for several weeks and survived by eating fruits of giant conifers that were the only available food in that area. You laugh and tell him, "that can't be true". Why?
Because conifers do not produce fruits
Why do Bryophytes, Lycophytes and Peridophytes prefer to grow in moist habitats closer to water?
Because they have swimming sperm that need a film of water
Mutualism
Benefit Both
Commensalism
Benefit one, harm to other
Parasitism
Benefit one, harmful to other
Which sequence represents the correct order in which land plants became more advanced in structure and function during their evolution?
Bryophytes, Lycophytes, Pteridophytes, Gymnosperms, Angiosperms
Coevolution for protection
Bullhorn ants live in hollow thorns of ant acacia plant The plant produces nectar and food bodies to feed ants The ants protect the plant from herbivores
Seeds Plants Appear in the
Carboniferous Era
Staminate
Carry only male organs
Ephedrine: for asthma relief
Comes from the Ephedra plant (Gnetophyta) (Originally used as a nutritional supplement, now classified as a medicine)
Monotropa
Completely heterotrophic angiosperm that draws nutrients from soil fungi. Plants can be parasitic in fungi
Anthers
Contain Microsporangia divides by meiosis...goes to microgametophytes (pollen)...sperm
Male Gametophytes in Seed Plants
Contained within the microspore Male Gametophyte produces sperm inside the pollen grain
Which two phyla are considered as the most primitive among Gymnosperms, and why?
Cycadophyta and Ginkgophyta because they have swimming sperm
What is the popular landscape plant?
Cycadophyta. Produce large cones that produce microspores and mespores. Gametophytes are extremely reduced to few cells
Cycaophytes
Dependent on the Sporophyte
Which came first; Monocots or Dicots?
Dicots, then monocots
Mycorrhizae inside plant roots come in two forms
Ectomycorrhizae Endomycorrhizae
Cycads have mutualistic symbioses with Cyanobacteria in roots
Example: Corraloid roots harboring Cyanobacteria. May form a ring with cyanobacteria.
When flowers are self pollinated, they get their own pollen onto the stigma of a flower, therefore, it can be considered as a form of asexual reproduction.
False, because pollen and eggs are not identical due to meiosis in sporangia
Your friend says; A symbiotic relationship between two organisms is beneficial to both organisms involved. You say:
False, these relationships may benefit both or only one partner.
Pistillate
Female organs only
Mycelium
Filaments aka HYPHAE make the body of the fungus (mycelium)
Nitrogen Fixation in Legume Root Nodules
Flavonoids secreted by plant roots to attract rhizobium. Rhizobium Enter the Root and colonize Plant root develops the nodule and accessory elements to house them. Bacteria Modify to life inside plant and fix nitrogen.
Highly Evolved Leaves
Floral parts
Monocotyledonous (monocots)
Flowers in threes, vascular bundles scattered, one pore/furrow in pollen. grasses, grains, orchids, palms etc.
Tight coevolution could be a survival strain
If one partner becomes extinct => other partner may be forced to become extinct or evolve fast. For 40 million years yucca plant and yucca moth coevolved. Neither can survive without the other.
Where is the sporophyte the smallest?
In Phylum Hepatophyta (Bryophytes)
Plant Diseases Caused By Bacteria
Internal Defenses to recognize pathogen Ex: Hypersensitive response and SAR
In Gymnosperms as well as in Angiosperms, the female gametophyte is very small. How does it feed the developing embryo?
It draws nutrients from the parent sporophyte tissues.
Ginkgo biloba is the only species in the phylum Ginkgophyta. Why have scientists given this one species its own phylum?
It is the only remaining species of a previously larger group
What does the microsporangia produce within the anters?
Male Gametophyte aka microgametophyte aka pollen grain
What does the ovule contain?
Megasporangium with one megaspore mother cell.
The development of female gametophyte
Megaspore mother cell is 2n Megasporangium is 2n Integument 2n Ovule is sporophyte tissue is 2n
The development of female gametophyte
Megaspores (n) Female Gametophyte is (n) Archegonia (n) Egg Cells (n)
How does meiosis increase genetic variation in plants?
Meiosis is a reduction division -shuffles alleles in homologous chromosomes -separates homologous chromosomes -endless new allele combinations -results in unique new cells -produces cells with half the number of chromosomes
The seed is what?
Mini embryo of the future sporophyte (2n). Dispersal stage of the life cycle. Dry seeds can withstand adverse conditions and can remain dormant for many years.
Phylum: Coniferophyta
Most diverse group among Gymnosperms Commonly known as "conifers" Highly resinous stems, Needle-like leaves, Cones bearing eggs/seeds or pollen examples: pines, junipers, firs, spruces
Fiddleheads
Newly forming fronds that are tightly coiled
Coevolution for dispersal of seeds by animals
Omphalocarpum fruit seedlings can grow in elephant shit
Where does pollen land?
On the stigman
Phylum: Ginkgophyta
Only one living species on earth Ginkgo biloba. May also be called maidenhair tree. Living fossil.
Where does development occur in Cycads?
Ovules with fertilized eggs develop into exposed seeds on megasporophylls
Among all land plants, which phylum carries the smallest and least advanced sporophyte generation?
Phylum Hepatophyta
True stems with vascular tissues can be seen among (choose all that apply)
Phylum Lycopodiophyta Phylum Pteridophyta Phylum Equisetophyta
Cycad corraloid roots in symbiosis with cyanobacteria
Plants will provide nutrients/protection to the cyanobacterium (ANABAEN, NOSTOC) which will provide fixe nitrogen and toxins to the plant Example: Azolla is symbiotic with Anabaena
Evolution
Process by which populations change with time due to selection pressure from the environment they live in
Mushrooms Eaten Are
Reproductive Organs of the fungus
Cross pollinating flowers
Show mechanisms that prevent self pollination and promote cross pollination
Whorl 4
(innermost) female reproductive organ - consists of one or several carpels (separate or fused into one structure
Bird-pollinated flowers
- Bright colored, mostly red - No landing platform Nectar present as reward
Butterfly-pollinated flowers
- Flowers are bright colored - Provide landing platform - Sweet fragrance - Nectar - Slender tubular corolla - - Butterflies evolved with long mouthparts (e.g. proboscis)
Importance of Gymnosperms
- Food and flavor for human use: pine nuts, juniper berries - Food for birds and other small animals
Self pollinating flowers
- Must be perfect flowers - Anthers and stigma mature at the same time - Anthers can touch stigma or placed above stigma - Usually less colorful
Bee pollinated flowers
- Not red, sweet minty fragrance - Provide landing platform for the bee to land on the flower - Provide nectar guides on petals
Fly-pollinated flowers
- Smells like rotten meat - red/brown colors - Nectar present Landing platform
Mechanisms to promote cross pollination
- Stamens below stigma - Imperfect flowers - - Self-incompatibility if perfect flowers - Male and female plants Ex: Squash
Bat-pollinated flowers
- Strong fermenting smell - night blooming large pale colored flowers - Nectar present
Moth-pollinated flowers
- White or light colored - Mostly open at night - Nectar & heavy fragrance - Landing platform present or absent (some moths hover, some land)
Abiotic agents: Wind or water pollinated flowers
- colorless, mostly imperfect flowers - No nectar, no fragrance - Large stigma - No / tiny petals
Mutualistic Coevolution Between Plants and Animals
- pollination - seed dispersal - protection
ABC Floral Development
-A only = sepals -A and B = petals -B and C = stamens -C only = carpels
Gametophytes and Sporophytes in the Sporic Life Cycle
-Bryophytes have smaller sporophyte that is dependent on gametophyte -Lycophytes and Pteridophytes have sporophyte independent of gametophyte -Seed plants have sporophyte completely dependent on gametophyte
Seeded Plant Evolution of Characteristics
-Chlorophyta (aquatic green algae, Dom. gametophyte, ZYGOTIC life cycle) -Bryopyhtes (non-vascular, Dom. gametophyte, SPORIC life cycle, homospory) -Fern Allies (vascular, Dom. SPOROPHYTE, STEMS AND ROOTS, MICROPHYLLS, HETEROSPORY) -True Ferns (TRUE LEAVES)
Order of seedless plant evolution
-Chlorophyta (green algae) -Bryophytes -Lycophytes (fern allies) -Pteridophytes (true ferns)
Characteristics of seed plants
-Dominant sporophyte - Gametophyte completely dependent on sporophyte - Well developed vascular system, roots, stems, leaves
The gametophytes of seed plants
-Extremely small, nonphotosynthetic and unisexual (separate male and female gametophytes)
What causes vegetative meristem to become floral meristems?
-Internal signals (hormomes/metabolites_ -Environmental cues (temp, day length, stress factors)
Meiosis events
-Meiosis I (PMAT I) Homologs seperate -Cytokinesis I -Meiosis II (PMAT II) Sister Chromatids seperate -Cytokinesis II
Lycophytes
-Phylum Lycopodiophyta -vascular system (stems, roots, microphylls) -FIRST SIGN OF HETEROSPORY
True Ferns
-Phylum Psilotophyta, Equisetophyta, and Pteridophyta -DOMINANT SPOROPHYTE -true leaves first seen
Bryopyhtes
-Phylums Hepatophyta and Bryophyta -next step from algae, need close water -moist environments -flagellated sperm need water -no vascular tissue -no true organs (stems, leaves, roots)
Cycads seeds and leaves..
-Seeds and leaves of cycads can be poisonous
What is a Fungi?
-Some Unicellular -Most are multicellular and filamentous
Fern Life Cycle
-Sporophyte produces sporangia (SORI) on underside of fronds -MEIOSIS IN SPORANGIA -Spores (haploid) -Gametophyte (haploid)
3 Stages of Development in Flowering Plants
-Vegetative Stage -Reproductive Stage -Senescence
Sporic Life Cycle
-all plants -alteration of generations -multicellular haploid and diploid generations alternate -lower plants (Bryophytes) have haploid dominant -lycophytes onward have diploid dominant
Gametic Life Cycle
-animals, some algae -produce gametes directly through meiosis -gamete only haploid stage -DOMINANT DIPLOID
Angiosperm characteristics
-arid, wet, aquatic, saline, hot, cold. Exhibit all growth forms (trees, shrubs, herbs, vines) - Mostly autotrophic, but few heterotrophic species
True Leaves
-branched veins -True Ferns onwards
How is pollen dispersed?
-by anther dehisence -pollen grains land on stigma -pollen tube grows inside the style to reach ovary -after pollenation, g cell nucleus divides by MITOSIS to produce 2 sperm nuclei -tube nucleus controls the pollen tube growth into an ovule
Importance of Bryophytes
-common starter species for poor soils -common foundation for food chains -wide distribution
Where does meiosis occur in the plant life cycle?
-diploid sporophyte produces haploid spores by MEIOSIS -haploid spores develop into gametophytes -gametophytes produce gametes by MITOSIS -haploid gametes (female+male) come together to form genetically unique sporophyte zygote
Bryophyte Life Cycle
-dominant gametophyte (haploid) -diploid sporophyte grows and depends on dominant gametophyte
Dicot seed
-each seed carries an embryo (future sporophyte) -endosperm recedes as two cotelydons that grow bigger as they extract nutrients from endosperm -mature seeds dispersed from parent plant -germinate into new sporophyte
Monocot seeds
-endosperm remains large -cotelydon is a small part of embryo
Phylum Bryophyta (mosses)
-erect body form -no vascular system (no stems/leaves/roots) -rhizoids to anchor -archegonia and antheridia form at gametophyte tips -sperm spreads by wind and water and swims to fertilize egg -diploid zygote forms -produces diploid sporophyte at female plant tip
Megagametophyte
-female -few cells inside ovule -contained and nourished within sporophyte
Pistil
-female part -ovary and bottom -stigma at top -style connects ovary to stigma
Sexual Reproduction in Plants
-female+male gametes = zygote -meiosis occurs in one stage in the life cycle -increases genetic variation -accelerates adaptations -promotes evolution -produces unique haploids/progeny
Archegoniophores
-female, in bryophytes -umbrella shaped with arms -produce eggs
Vegetative Stage
-first stage of flowering plant development -increase size -produce more roots, leaves, and branches
Dicotyledonous (dicots
-flowers in 4/5s -vascular bundles in rings -three pores or furrows in pollen peas, roses, oaks, cacti etc.
How Angiosperms and Gymnosperms differ
-flowers with male and female spores -ovules are enclosed in sporophytic tissues, which are fruits after fertilization
Gemmae cups in Bryophytes
-for asexual reproduction -gametes produced by MITOSIS
Zygotic Life Cycle
-in protists (algae) -DOMINANT HAPLOID -produce spores through MEIOSIS -zygote is the only diploid stage
Megaspores
-large -female -in megasporangia
Microphylls
-leaves with a single vein -in lycophytes
Microgametophyte
-male -2 cells inside pollen -dispersed from sporophyte
Stamen
-male part -anther at top -filament raises it to stigma
antheridiophore
-male, in bryophytes -disc shaped -produce flagellated sperm
Fruits
-mature ovaries -carry seeds -highly evolved to protect young seeds -disperse mature seeds
How is pollen formed?
-meiosis inside of MICROsporangia in anthers prodice microspores that become pollen
What happens in the ovule during sexual reproduction?
-meiosis inside ovule produces megaspore that develops into a female (mega) gametophyte -pollen tube grows into ovule -one sperm nucleus fertilizes the egg cell nucleus
Shrinking Gametophytes in Seed Evolution
-microscopic gametophytes in seed plants -exist within spores -depend on sporophytes
Importance of true ferns
-most of oil reserves from fossilized ferns -ornamental house plants
Phylum Psilophyta (whisk ferns)
-most primitive ferns -dichotomous branched stem (splits into two) -no leaves or roots -homosporous
Where do the two sperm nuclei go when in the ovary?
-one fertilizes the egg cell nucleus to form 2N zygote -the other joins the two polar nuclei to form 3N endosperm
Pollination and double fertilization
-pollen grain lands on stigma -pollen tube germinates into ovary -pollen tube carries two sperm nuclei -one sperm fertilizes egg to form 2N zygote -other sperm joins with two polar nuclei to form 3N endosperm
Endosperm
-provides food for embryo
Reproductive Stage
-second stage of flowering plant development -produce flowers, fruits, and seeds for sexual reproduction
Phylum Equisetophyta (horsetails)
-segmented stems arise form rhizome -tiny microphyll leaves -TRUE ROOTS -homosporous -sporangia in cone called STROBILUS
Phylum Hepatophyta (liverworts)
-simple body form -rhizoids to anchor -gametophyte forms archegoniophores and antheridiophores to produce gametes -sperm fertilizes egg to form diploid zygote in archegonia -sporophyte grows from zygote, still in archegoniophore -sporophyte, thru meiosis, produces haploid spores -haploid spores germinate to form haploid gametes
Microspores
-small -male -in microsporangia
Early plants
-small -no roots, stems, flowers, or seeds -evolved from green algae (chlorophyta)
Heterospory is seen in
-some lycophytes -some pteridophytes -all gymnosperms -all angiosperms
Senescence
-third stage of flowering plant development -individual organs or whole plant wither and die :(
Pollen grains contain
-tube cell -tube cell nucleus -generative cell
After fertilization in Angiosperms
-zygote develops into embryo (future sporophyte) -the 3N endosperm provides nutrition to the embryo -ovule develops into seed that protects embryo -integument becomes seed coat -ovary develops into fruit
After fertilization in plants
-zygote is the fertilized egg -embryo inside seed -becomes future sporophyte
Result of Meiosis in Plants?
4 genetically different haploid spores
Mycorrizhal
90% of plants benefit from it. Increases surface area for absorption. Plant will provide carbs to the fungus.
Phylum: Gnetophyta
About 70 living species Very unusual looking, often in dry habitats Some genera show features similar to Angiosperms May not be the true lineage of Angiosperm evolution
Coevolution
The process by which two or more groups of organisms influence each others evolution. May be beneficial or rivalry
What does the whole ovule in gymnosperms develop into?
The whole ass seded. The seed coat is 2n. It is also a modified integument from the parent plant. Embryo is 2n and is the new sporophyte.
Gnetophytes have some advanced characteristics in common with angiosperms. Why are they classified as gymnosperms?
Their seeds are naked
Which of these are true about heterospory? Choose all that apply. Penalty for wrong choices. (Hint: 3 correct answers)
There are megaspores and microspores Heterospory first appeared in Lycophytes Heterospory paved the way for plants to evolve seeds
Why are gymnosperm seeds said to be naked?
They are not enclosed within a fruit.
What characteristics among these are typical to both gymnosperms and angiosperms? Choose all that apply. Penalty for wrong answers. (Hint: 4 correct answers)
They are vascular plants with true stems and leaves Their female gametophyte is contained within the sporophyte Their pollen represent the male gametophyte Their male gametophyte travels to the female gametophyte
Which statement is true about a difference between fern allies and true ferns?
True leaves are present in true ferns but not in fern allies
During the event known as double fertilization, which of these is/are fertilized by a sperm nucleus to generate the 3N endosperm?
Two polar nuclei
Dicots and monocots differ from each other in several ways. Select all answer choices that describe differences between them. Penalty for wrong answers. (Hint: 3 correct answers)
Venation pattern in the leaves of dicots and monocots differ Dicots produce two cotyledons, monocots produce only one The arrangement of vascular bundles in dicot and monocot stems differ
Seed Plant Female Gametophytes
Within the ovule of sporophyte. They produce egg cells.
The fruit is;
a mature ovary
Whorl 3
Stamens - male reproductive structures each consists of a filament and anther lobes
What happened to the gametophyte stage during the course of evolution of land plants?
became smaller and more dependent on sporophyte
Why have some plants coevolved with animals for pollination, rather than depending on physical forces like wind and water for pollination?
because coevolved animals are more reliable in carrying pollen between flowers
Which of these is NOT a part of a flower?
bract
Phylum Cycadophyta
cycads (i.e. sago palm) Primitive Group. Flagellate sperm similar to Bryophytes, Lycophytes, and Pteridophytes.
Whorl 2
usually large, colorful, showy Adapted to attract pollinators to the flower
Megaspore cell will..
divide by meiosis into four haploid cells where one cell will become the megaspore and the other three cells will degenerate
What is the unique feature of the Angiosperm Life Cycle?
double fertilization
How does the megagametophyte develop from this megaspore?
each megaspore produces a megagametophyte (female gametophyte), which ultimately produces female gametes (eggs). Fusion of an egg and a sperm creates a zygote and restores the 2n ploidy level. The zygote divides mitotically to form the embryo, which then develops into the sporophyte.
What is carried inside the seed of a gymnosperm?
embryo of the future sporophyte
Fronds
fern leaves
Angiosperms
flowering plants Phylum Anthophyta Most advanced evolutionary features, therefore dominant
Gnetophyta advanced feature
has tracheids and vessel elements
Ectomycorrhizae
have hyphae that do not enter into root cells
Cycadophyta, Ginkgophyta and Coniferophyta
have only tracheids in the xylem for water transport (primitive feature
Rhizomes
horizontal underground stems, give rise to roots
The ABC model explains;
how different whorls of flower parts are determined
The double fertilization is seen;
in all angiosperms and some gymnosperms
What words should go in the blanks? In the life cycle of a land plant, diploid sporophyte produces spores using cell division by ____, and haploid gametophyte produces gametes using cell division by ____ .
meiosis, mitosis
In seed plants, which of the following would be dispersed away from the parent plant?
microgametophytes and seeds
The zygote of an angiosperm undergoes _______________ to produce the embryo, that develops into the __________________ .
mitosis, future sporophyte
Leaves come from
modified stems and branches
Monocot endosperm
more than in dicots
Seeds Plants are the
most advanced vascular plants
How do you tell if a symbiotic relationship is a mutualism or commensalism?
mutualism benefits both, commensalism benefits one without harming the other.
A farmer owns a successful organic apple orchard. For many years he has had excellent yield from his trees. This year his orchard yielded very poorly even though he had not changed his farming strategies, and weather was very consistent. Which of the following reasons might best explain the drop in fruit production?
only answers A and C could be possible explanations
double fertilization
only found in angiosperms and produce a structure called endosperm inside the seed
Perianth
petals and sepals
Refer to the ABC model of floral organ development. Gene A is expressed in whorls 1 & 2, gene B is expressed in whorls 2 and 3, gene C is expressed in whorls 3 & 4 (whorl 4 is the innermost). A scientist used genetic engineering techniques to express gene B in all whorls. What would the pattern of floral organs in the resulting transgenic plant be?
petals, petals, stamens, stamens
Pathogenic fungi
plant diseases are caused by fungi Ex; mildews, rots, rusts, smuts, anthracnose Plants have also developed mechanisms to resist infections (coevolution for defense)
Your aunt who is highly allergic to bee stings, loves flowers but would like to keep bees away. What would be your best advice to her about the types of flowers she should have in her garden?
plant mostly bright red, long tubular flowers without landing platforms
Whorl 1
sepals - usually small, green (photosynthetic) protects the unopened flower in bud
Dicot endospem
smaller and gets fully eaten by two cotelydons
The microgametophyte of a Gymnosperm should produce;
sperm
A plant lives in a remote valley, with only a few other flowering plant species nearby. It reproduces only sexually by being pollinated only by one specific butterfly species, which pollinates most of the plant species in the valley. Also living in the valley is a bird that eats only the fruit of the plant and preys on the butterfly. Extinction of which of these three species would cause the extinction of the other two?
the butterfly
What is the sexual organ in Angiosperms?
the flower
According to the description of "true leaves", a feature seen in true leaves but not in microphylls is;
the presence of branched veins
What is a correct statement describing a relationship between ovules and seeds in "both gymnosperms and angiosperms"?
the unfertilized egg cell inside the ovule becomes the embryo inside the developing seed after fertilization
In the evolutionary history of land plants, which of these is a landmark evolutionary feature appeared in Lycophytes?
they evolved the dominant diploid sporophyte generation
What is always true about heterosporous plants?
they produce small male microspores and large female megaspores
What is the advantage to a tomato plant in having green unripe fruit and red ripe fruit?
this lowers the chance that immature seeds are dispersed by animals
Rhizoids
anchors, but does NOT absorb anything
All living gymnosperms
are woody plants. produce secondary growth by the activity of vascular cambium and cork cambium
Which of the following statements most accurately explain what recent molecular evidence shows about monocots and dicots?
dicots were the first to emerge, and monocots separated later from a dicot ancestor
receptacle
Four whorls rest on here
How does self-incompatibility happen
Genes activated on the stigma prevent pollen from the same flower from germinating on the stigma. Sometimes, genes activated in the pollen abort the pollen tube growth
Nutrition supplements
Ginkgo extract improves blood circulation to the brain and lungs
Plants Interaction with Fungi
Good: Mycorrhizal fungi. Decomposers that recycle nutrients from dead plant matter back to soil Bad: Pathogens that cause diseases
Plants interaction with Prokaryotes
Good: Nitrogen Fixation. Protection Bad: Bacterial Diseases
Fungal Mycelia
Help absorb phosphorus and nitrogen from soil
What was the gateway to seeded plant evolution?
Heterospory
Receptacle
The base of a flower
Carpels
The female reproductive organ of a flower, consisting of the stigma, style, and ovary.
Pollination syndromes
The morphology and behavior can help predict the mode of pollination. Ex: Abiotic and Biotic Agents
Heterospory is a feature that is invariably found in;
all seed plants
Homosporous
all spores are the same size
What is the function of the pollen tube in an Angiosperm?
delivering two sperm into the ovule
Here is something to think about. Read patiently! You treated a developing flower of a self-pollinating diploid angiosperm with a chemical that disrupts sister chromatid separation in the anaphase II of meiosis during both microspore and megaspore formation, producing spores that have double the number of chromosomes. If the plant pollinates itself, what would you expect as the ploidy of the integument, zygote and endosperm?
integument 2N, zygote 4N, endosperm 6N
Cyanobacteria in symbiosis with roots
produce a toxic amino acid
Endomycorrhizae
produce structures that enter root cells
Male Cone of Cycadophyta
produces microspores and pollen grains on microsporophylls
Female Cone of Cycadophyta
produces ovules on megasporophylls
