The seed is an important advancement why?
Extra layer of embryo protection
Seeds can be dormant and survive until environmental conditions are favorable
What does "gymnosperm" mean? Why?
Lack the flowers and fruits of angiosperms and the seeds are not enclosed by sporophyte tissue
Reproduction varies: which two have motile sperm and which have non-flagellated sperm?
Cycads and Ginkos have motile sperm, Conifers and Gnetophytes have non-flagellated sperm
Conifers; includes the tallest (coastal redwoods) and most massive (giant sequoia) trees
Where are conifers usually found?
Drier and colder temperate regions (great forests in the Northern hemisphere)
Various species are useful to humans how?
Timber for construction
Taxol (used to treat cancer)
All seed plants are _____ and different spore types therefore give rise to...
Heterosporous; two different gametophytes
Male gametophytes (____ ____) develop from ______ found on male cones
Pollen grains; microspores
Pollen grains develop air sacs to assist in dispersal
Genera Ephedra is used to make ephedrine, which is a...
Drug that was used to treat respiratory problems (was pulled from the market because it caused heart attacks/ strokes)
Phylum Gingkophyta- is unique because it is...
The last of its kind (only one remaining species)
No longer exists in the wild
As compared to gymnosperms, angiosperms have/are...
Have non-motile sperm
Ovules that are enclosed within sporophyte tissue at the time of pollination
Outermost whorl is the...
Next whorl consists of...
Sepals (most flowers have 3-5, they are usually green)
Next whorl consists of petals (usually colored to attract pollinators)
Third whorl contains _____, which produce...
Stamens; male gametophytes (pollen)
NOT ALL FLOWERS HAVE STAMEN
At the center of the fourth whorl is the...
Gynoecium, which houses the female gametophytes
Can have more than one carpel
Some flowers secrete nectar from
Nectar contains sugars, amino acids, and other substances to attract pollinators
Angiosperm life cycle
Megaspore mother cell undergoes meiosis, followed by mitosis
Microspore mother cells also undergoes meiosis followed by mitosis (results in pollen grain, which is the male gametophyte)
During pollination, the pollen tube enters the _____ ______ and discharges its contents (___ ___)
Embryo sac; two sperm
Both sperm are functional-
One unites with the egg and forms a zygote
The other sperm and the two polar nuclei unite forming a triploid endosperm nucleus
Bird pollinated flowers are often what color?
Red (insects see in UV and aren't usually attracted to red)
Other insects that pollinate
Butterflies (flowers may have a perch)
Moths (pollinate at night, so flowers are scented and white)
Beetles and flies (flowers sometimes smell like rotting flesh)
Bats and small mammals
Some flowers (oaks, birches, cottonwoods, grasses) use _____ pollination
Wind; small, odorless flowers are grouped in large numbers and often hang down to better catch wind
The outer layer (integument) develops into
An impermeable seed coat (encloses the dormant embryo and stored food)
Seeds are important in four ways
1. Seeds maintain dormancy in unfavorable conditions
2. Seeds afford maximum protection when the plant is the most vulnerable
3. Seeds contain food to permit young plants to grow before photosynthesis begins
4. Seeds are adapted for dispersal (allows invasion of new habitats)
Other adaptations ensure that seeds will only germinate under proper conditions
-Some seeds only germinate when inhibitory chemicals leak out into the environment (requires water)
Some seeds require cold period (stratification)
Cones may not open to let out seeds unless exposed to heat from a fire (fire clears out competition and releases nutrients into the soil)
Some seeds only germinate after being passed through the digestive tract of the animal (which ensures dispersal), why?
Digestive enzymes break down the seed coat
Feces provide a natural fertilizer
Fruits with fleshy coverings that are shiny black, red, or blue are usually dispersed by