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What prohibited invasion of terrestrial plants?
Lack of a protective ozone layer
What were the ancestors of land plants?
the aquatic algae
What three things did plants have to overcome?
- absorbing minerals
- conserving water
- reproducing on land
How did the plants solve the things they had to overcome?
- absorbing minerals: formed a symbiotic relationship between fungi and the roots of plants
- conserving water: developed cuticle, made specialized pores called stomata
- reproducing on land: eggs surrounded by jackets of cells and sperm enclosed in pollen grain so as to not dry out
What do the plants provide the fungi with and vice versa in the symbiotic relationship?
- Plants provide fungi with carbohydrates
- Fungi absorb phosphorus and other minerals needed for plants
What did the stomata enable?
Carbon dioxide to enter a plant and permit water vapor and oxygen gas to exit
What three specialized tissues did palnts evolve and develop?
What are the xylem?
hard walled cells that transport water and dissolved minerals up from the roots
What are the phloem?
soft walled cells that conduct carbohydrates away from the leaves and stems
How is plant growth produced?
By adding new cells to the tips of the body called meristems
What are the most abundant and most familiar group of seedless vascular plants today?
What are the live cycles of non-vascular plants dominated by?
A gametophyte generation
What were the first seed plants?
What two kinds of gametophytes do seed plants produce?
- a very tiny male gametophyte (microgametophyte)
- a relatively large female gametophyte (megagametophyte)
What happens when an egg inside of an ovule is fertilized?
The ovule and its contents become a seed
How are pollen grains transported?
By wind, insects and other animals
What is pollination?
Transportaion of pollen grains to a femal reproductive structure of a plant of the same species
What happens when a pollen grain reaches a female reproductive structure?
A pollen tube grows from the pollen grain to an ovule
What are gymnosperms?
trees that produce seeds and cones and are called conifers
What are the talles living vascular plants?
The giant redwoods of coastal California and Oregon
What are the oldest living vascular plants?
bristlecone pine (more than 5,000 years old)
What is a seed?
A sporophyte plant embryo surrounded by a protective coat
What is a seed coat and what does it do?
- The hard cover of a seed
- Protects the embryo and other tissues in the seed from drying out
In what three ways have seeds enabled plants to better live on land?
How are seeds helful through dispersal?
- Dispersal: enable the offspring of plants to be dispersed to new locations to prevent the parent and ofspring from competing with each other
- Nourishment: abundant food stored in them as a source of energy for plant embryo
- Dormancy: wait till conditions are favorable (moisture is present)
What do many seeds have to aid in dispersal?
Appendages such as wings to help wind, water or animals carry them
What are the most successful of all plants?
What percent of all living plants are angiosperms?
What are flowers?
Reproductive organs of angiosperms
What are the four whorls of appendages of a flower?
What is the Calyx?
- Outermost whorl of a flower
- consists of sepals (modified leaves)
- protects a flower from physical damage while in bud
What is the Corolla?
- the second whorl of a flower
- consists of petals (modified leaves)
- produces vividly colored pigments
- and/or fragrances to attract pollinators
What is the Androecium?
- third whorl of a flower
- produces microgametophytes (pollen grains)
- made up of stamens consisting of thread like filaments
- topped by anther (pollen containing sac)
What is the gynoecium?
- fourth whorl
- has ovules in which megagametophytes devleop
- one or more pistils
- style with swollen sticky tip (stigma)
What happens when a flower is pollinated?
Pllen tube emerges from each pollen grain and grows through the style and into the ovary
How do bees locate sources of nectar?
Odor then color and shape
What do the seeds of angiosperms develop that those of gymnosperms don't?
Highly nutritious tissue (endosperm)
Where are food reserves stored in, in angiosperms?
cotyledons (seed leaves)
What are dicots and what are monocots?
- dicots: two cotyledons
- monocots: one cotyledon