Chapter 30 Flashcards
What are seeds?
plant embryo and food supply with a protective coat
What are 5 characteristics of seed plants?
Reduced gametophytes
Heterosporous
Ovules
Pollen
Does not require water for fertilization
What are two advantages of reduced gametophytes?
Most are microscopic in seed plants
Size allows them to develop from spores retained within the sporangia of the parental sporophyte
Why is developing inside the parent sporophyte beneficial? (2)
Reproductive tissue of sporophyte shields the gametophytes from UV radiation and prevents drying out
Enables gametophyte to obtain nutrients from the parent
What does heterosporous mean?
produces two kinds of spores
What produces megaspores, how many gets produced, and what do the megaspores rise into?
megasporangia
Each megasporangium gives one megaspore
Rises into female gametophytes
What produces microspores, how many gets produced, and what do the microspores give rise into?
microsporangia
Each microsporangium produces many microspores
Gives rise to the male gametophyte
Where is the megasporangium found?
The seed plant retains megasporangium within the parent sporophyte
What is integument?
a layer of sporophyte tissue enveloping and protecting the megasporangium
how many integuments do gymnosperms and angiosperms have?
Gymnosperm has one integument
Angiosperm has two integuments
What is an ovule?
a structure consisting of the megasporangium, megaspore, and their integuments
where does the female gametophyte develop and what does it produce?
develops inside it from a megaspore
produces one or more eggs
what is a pollen grain, what does it form from, and what does it give rise to?
male gametophyte enclosed within a pollen wall
Formed from a microspore
After germinating, it gives rise to a pollen tube that discharges sperm into the female gametophyte
what is sporopollenin?
molecules in the pollen wall protecting the grain as it is being transported
What is pollination?
transfer of pollen to the ovule
what is the benefit of pollination?
Allows seed plants to colonize dry habitats
what is the sporophyte embryo, and what does it develop into?
developed zygote after a sperm fertilizes an egg in a seed plant
Ovule develops into a seed
what are three advantages of seeds?
Multicellular, unlike unicellular spores of seedless plants and mosses
Can remain dormant for long periods of time
They have a supply of stored food
What are the two clades of extant seed plants?
gymnosperm
angiosperm
What is a gymnosperm, and what kind of plants are they mostly?
naked seeds exposed on modified leaves, usually forming cones
Often conifers- cone-bearing plants
what are angiosperms?
seeds enclosed in chambers that mature into fruit
what is the sporophyte of a pine tree, and where is the sporangia found?
the pine tree itself
in the cones
What do pine trees possess?
small pollen cones and large ovulate cones
what do the cones do?
Undergo meiosis to produce haploid microspores
what do the microspores develop into in pines?
pollen grain
How is pollen released in pine cones?
dispersed in large amounts
How long does gametophyte production take?
Takes 3 years for the gametophytes to be produced, be brought together, and seeds to form
How are pine seeds dispersed?
Seeds are dispersed as the scales separate
where did early gymnosperms exist, what did they replace, and what were their role?
Lived in moist, carboniferous ecosystems dominated by seedless vascular plants
As the climate dried, gymnosperms replaced the seedless vascular plants
Served as food supply for giant herbivorous dinosaurs
What is included in Phylum Cycadophyta, 3 characteristics, and their environmental population status?
Cycads
Large cones
Palmlike leaves
Flagellated sperm- descended from seedless vascular plants
Endangered
What is in Phylum Ginkophyta, and what is a characteristic?
Only ginkgo biloba remains
Flagellated sperm
What is included in Phylum Gnetophyta, and where do they exist?
Includes gnetum, ephedra, and welwitschia
Range from tropical to rid environments
How large is Phylum Coniferophyta, what do they consist of, and 2 characteristics?
Largest gymnosperm phyla
Consists of conifers
Woody or fleshy cones
Evergreen
What are angiosperms called, and how common are they?
Aka flowering plants
Most diverse and widespread of all plants
What phylum do angiosperms belong to?
Anthophyta
What is a flower, and how are they pollinated?
unique angiosperm structure for sexual reproduction
Pollenated through insects or wind
What are the four main floral organs?
Sepals
Petals
Stamen
Carpels
What is the sepal, its color, and its role?
base of the flower
Usually green
Encloses the flowers before opening
What are petals, and its sexual status?
brightly colored organs to attract pollinators
Both petals and sepals are sterile
What does the stamen produce, and what does it consist of?
produces microspores that develop into pollen grains containing male gametophytes
Consists of filament (stalk) and anther (terminal sac)
Where is pollen produced?
anther
What does the carpel produce, and what does it do?
produces megaspores and female
gametophytes
Constraints the seeds
What is the stigma?
sticky tip of carpel that receives pollen
What is the style?
leads from stigma to the base of the carpel
What is the ovary?
base of carpel containing ovules
How do complete and incomplete flowers differ?
Complete flowers- flowers with all four organs
Incomplete flowers- those that lack one of the organs
What is a fruit, and what does it do?
mature ovary after fertilization
Protects seeds and aids in dispersal
What kind of fruits exist, and their roles?
Can be fleshy (tomatoes) or dry (beans)
Dry fruits split to release seeds
Fleshy fruits soften and ripen
What is unique about dandelion and maple fruits?
seeds within fruits that function as parachutes for dispersal
How did coconuts adapt?
to disperse by water
What is the point of sweet fruit?
Sweet fruit seeds get consumed and excreted
What do angiosperm sporophyte produce?
microspores and megaspores
Where is the male gametophyte, and where does it develop?
in pollen grain
develops in the anters
What makes up the male gametophyte, and their roles? (3)
Has two haploid cells
Generative cell- divides forming two sperm
Tube cell- produces pollen tube
What is an embryosac, and what does it consist of?
female gametophyte that develops in the ovary
Consists of the egg
Where is pollen carried to?
stigma
How do flowers enhance genetic variability, and an example?
ensures cross-pollination
Ex- maturation of anther and carpel at different times
What does the pollen grain do?
absorbs water and germinates after adhering to the carpel
What does the tube cell produce?
Tube cell produces pollen tube, growing down the carpel
What does the pollen tube do?
Tube penetrates micropyle
(Pore in the integuments of the ovules)
What does the pollen do after penetration?
Discharges two sperm cells
what do the two sperm cells do, what is the process called, and what is unique about this process?
One sperm fertilizes egg to form a diploid zygote
Other sperm fuses with the two nuclei in the large central cell of female gametophyte, producing triploid cell
Aka double fertilization
Unique to angiosperm
What does the ovule become?
matures into a seed
What does the zygote develop into?
an embryo with root and leaves called cotyledon
What do triploid cells develop into, and what is the reason?
develops into endosperm
(Tissue rich in starch to nourish embryo)
Synchronizes food storage of seed with embryo development
How did angiosperm evolve? (2)
Still unknown how angiosperms arose from earlier seed plants
Sudden geographically widespread appearance of angiosperm
when did angiosperms originate, and when did they dominate?
originated early Creceous
by mid-Creceous, they dominated
When was angiosperm found, and when did they diversify?
after the Jurassic period
Group arose and began to diversify over 20-30 million years
What was the ancestor of angiosperms, and what are extant angiosperms related to?
Angiosperm common ancestor was probably woody
Extant angiosperm may be more related to extant woody seed plants than extant gymnosperm
What were early angiosperms like?
Early angiosperms were shrubs that had small flowers
What negative impacts do herbivores have on plants, and how do plants respond?
Herbivores reduce plant’s reproductive success by eating it
Plants that develop a defense system is favored by natural selection
What is an example of beneficial mutual interactions that produce evolutionary effects in plants?
pollination
how does bilateral and radial symmetry differ?
Bilateral symmetry- flower can be divided into equal parts by a single imaginary line
Radial symmetry- petals, stamens, and carpels radiate out from a center
Can be divided into two equal parts at any line
How does flower shape affect evolution? (2)
affect rate of which new species form
Bilateral symmetry makes it more likely that pollen transferred will make contact with a stigma of another flower- increasing its genetic diversity and speciation compared to radial species
What are monocots, 5 characteristics, and examples?
species with one cotyledon
Parallel leaf vain
Scattered vascular tissue
Fibrous root system- no main root
Pollen grain with 1 opening
Floral organs usually in multiples of three
Ex- maize, rice, wheat
What are dicots, and what kind of classification are they?
species with two cotyledon
Paraphyletic
What are eucots, 5 characteristics, and examples?
true dicots
Netlike leaf vein
Ringed vascular tissue
Taproot is present
3 openings in pollen grains
Flower organs in multiples of 4 or 5
Ex- snow pea, oak, maple, peas, and roses
what do basal angiosperm include, what were they formerly, and examples?
includes flowering plants belonging to the oldest lineage
3 of four small lineages of former dicots
Water lilies, star anise
What are magnolids, what are they related to, and examples?
Fourth lineage of basal angiosperms that evolved later
More closely related to eudicots and monocots
Ex- magnolias, laurels, black pepper
How are angiosperms distinguished? (2)
Number of cotyledons
Further distinguished using flower and leaf structure
Different products of seed plants (7)
Maize, rice, wheat, potatoes, cassava, and sweet potatoes make up 80% of diet
Also used to feed livestock
Current crops arised from artificial
selection and domestication
Act as sources of edible products- tea, and cocoa
Spices- vanilla, basil, cinnamon
Source of wood
For medicine- willow leaves and bark
What is a threat to plant diversity, and what two things does it lead to?
Human population threatens plant species space and resources
Leads to loss of insect and rain forest animals
Also reduces CO2 absorption and contributes to global warming
