Chapter 30: Plant Diversity II
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Seed plants originated ______ years ago!
360 Million years ago!!
Embryo and it's food supply surrounded by a protective coat
Traits of a seed:
- Seeds can move away from mother plant
- Seed plants are dominant producers on land
- 12,000 years ago humans began cultivating plants
Which type of plants are dominant producers on land?
____ years ago humans began cultivating plants.
12,000 years ago
What are the two key adaptions for life on land for plants?
Name the 5 derived traits of seed plants (ReGa HOPS)
- Reduced Gametophytes
Reduced gametophytes: microscopic male and female gametophytes (n) are nourished and protected by the _____ (2N).
- microspore gives rse to male gametophyte
- megaspore-gives rise to female gametophyte
two different types of spore
gives rise to male gametophyte
gives rise to female gametophyte
What happens in the Ovules?
Inside each ovule a female develops from a megaspore and and produces one or more eggs.
What are the advantages of pollen?
- grains make water unnecessary for fertilization;
- pollination occurs when pollen is transferred to the part of the seed plant that contains the ovules
What is the advantage of Seeds vs spores?
- seeds survive better than unprotected spores
- can be transported long distances (by wind or animals)
Plants with "naked seeds"
Why are gymnosperms called "naked seeds" ?
Beause the ovules are not completely enclosed in sporophyte tissue at pollination
Does pollination occur before or after fertilization?
Before!! The gymnosperm must be pollinated before it can be fertilized.
pollen has been deposited on the female part of the plant
fusion of sperm and egg nucleus
What are the 4 groups of gymnosperms? (ccgg)
- 1. coniferophytes
- 2. cycadophytes
- 3. gnetophytes
- 4. ginkgophytes
Which gymnosperms lack flowers and true fruits?
ALL OF THEM!
What is the largest gymnosperm phylum?
Name the traits of Conifers, and give some examples:
- Tallest and oldest vascular plants
____ are an exemplary conifer genus
Characteristics of pines
- Clusters of two to five rough, needlelike leaves
- produce male and female cones
- microsporangia develops into four-celled(n) pollen grains
- megasporangium(2n) produces megaspores one of which becomes female gametophyte (2n)
The microsporangia of pines develop into ___ celled pollen grains.
Megasporangum produces ____
One of the megaspores produced by megasporangium in pines becomes the _____.
female gametophyte (diploid)
Which of the following components of the pine life cycle is haploid?
A. microsporangia --> four-celled pollen
B. megaspore --> female gametophyte
C. microsporangium --> megaspores
A. four-celled pollen is haploid (n)
(this multiple choice question has been scrambled)
In a fertilized pine gametophyte, which components are diploid and which are haploid?
a. seed coat
b. food reserve
- Diploid: seed coat
- Haploid: Food reserve, embryo
Cycads resemble ___ but are NOT flowering plants.
- Heights of 15 meters or more
- Produce cones
- Some female cones are huge
- Sperm have flagella
- Life cycle like that of conifers
- Only gymnosperms to have vessels in their xylem
- Welwitschia from southwest Africa
- Ephedra found worldwide; source of ephedrine
Which gymnosperms are the only ones to have vessels in their xylem?
Name two Gnetophytes:
- Welwitschia - found in southwest Africa
- Ephedra - worldwide
This gnetophyte is the source of Ephedrine
- Epherda (Mormon Tea)
- Taken off the market because it is linked to strokes and heart attacks
- Only one species remains in existence
- Ginko Biloba- has broad leaves that are shed in the fall
- Sperm have flagella
- Fleshy covering of female seeds is very stinky like rancid butter
What does Dioecious mean?
Two houses: separate male and female trees (Gingko Biloba)
What is the only species of ginkophyte left?
Which two types of gymnosperm have sperm with flagella?
The flowering plants
There are more than _____ known species of angiosperms.
What are the two defining characteristics of Angiosperms?
- Enclosed ovules within diploid tissue at the time of pollination
- Produce fruit (from the carpel)
What was the first angiosperm?
- Angiosperm origins are a mystery!
- Amborella trichopoda are thought to be the closest living relative to the first angiosperm
Two clades of angiosperms?
- Archaefructaceae (extinct family) may be a sister clade, but debated
- Amborella trichopoda
What houses the gametophyte generation of angiosperms?
What are flowers, reallt?
Modified stems that bear modified leaves
Flowers have ___ whorls:
Name the 4 whorls of a flower, from the inside to the outside (GAPS):
- Gynoecium (female house) = one or more carpels
- Androecium: (male house) = stamens
- Petals: 3-5 and often colored
- Sepals: 3-5 and green, leaflike
Stamens produce (diploid/haploid) pollen (the male gametophyte)
Carpel has three major regions:
In angiosperms, the ___ becomes the fruit.
Carpals contain the (male/female) gametophyte
Why are fruits adapted?
What are the three layers of the ovary wall?
Collectivly, the three layers of the ovary wall (exocarp, mesocarp, and endocarp) are known as _____.
The fates of the three layers of the ovary determine wheather the fruit is ____, or ____ and ____.
Fleshy, or dry and hard
Why have angiosperms produced seeds?
To colonize large areas
What are the main ways that fruit is dispersed for colonization?
- 1. Fruit with black, blue or red colors are dispersed by birds and verterbrates
- 2. Fruits with hooked spines (burrs) are dispersed on animal fur or clothing
- 3. Squirrels and other mammals bury acorns or other nuts that may sprout
- 4. Fruits or maple, ash, and elm trees have "wings" that aid in wind dispersal
- 5. Orchids have dustlike seeds that are wind blown
- 6. Dandelions have seeds with parachutes that float on wind currents. Milkweeds, cottonwood trees, willows, goats beard, etc
- 7. Coconuts can float on water for dispersal to another island.
Fruits of which colors are disperse by birds and vertebrates?
Red, Black, Blue
___ have dustlike seeds that are wind blown
What fruit floats on water to be dispersed on other islands?
Fruits with a single pit
- Apples and pears
- Parts of 5
- Members of the rose family
Most species of angiosperms use flowers to do what?
Attract pollinators and to reproduce
How do angiosperms use flowers to attract pollinators?
Flowers have ultraviolet landing strips for insects that guide them to the pollen
Are all flowers pollinated by pollinators?
No. Some are pollinated though wind-pollination
The angiosperm life cycle includes ____ fertilization
In angiosperms, the megaspores produce how many nuclei? Haploid or diploid?
8 haploid nuclei
Female gametophyte consists of embryo sac and the 8 nuclei in only___ cells.
in only seven cells
What is the most important part of the female gametophyte in angiosperm?
- The egg
- Two polar nuclei in the single cell
Pollen grains form a ____ toward the embryo sac after landing on the receptive stigma.
How many sperms pass through the pollen tube in the reproduction of angiosperm?
Two sperm pass through the pollen tube during angiosperm fertilization. What does each do?
- One fuses with the egg to form the zygote
- Other fuses with polar bodis to form triploid endosperm nucleus
Where does the triploid endosperm nucleus come from in angiosperm reproductioin?
From the fusion of one out of two pollen sperms with the polar bodies in the female gametophyte.
What is the purpose of the triploid endosperm nucleus in angiosperm reproduction?
To nourish the embryo (kind of like the placenta in pregnant females)
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