iii. plant classification

(pp. 551-552)
Plants are placed into groups based on structural and functional similarities, but all plants share the following
A. Plants are _eukaryotic____, _multicellular____ organisms with _organs & organ systems_________________
B. All plant cells have _cell walls___ composed of _cellulose_____.
C. Plants are _autotrophic____, which means they can use energy from the _sun___ to make _glucose__ in
_photosynthesis___. Photosynthesis takes place in the _chloroplasts_____ of plant cells. The equation for
photosynthesis is _CO2 + H2O → C6 H12 O6 + O2____________________.
D. Plants are _non-motile_____; therefore, special adaptations are required for _reproduction_______.
(pp. 579 - 597)
A. Plant Transport
Larger plants must have a way to transport _water______ and _minerals___________. This is carried out by
two types of _vessels____. Together the vessels (cells working together) make up a _tissue______ in plants
known as _vascular_______ tissue. Plants are divided into two groups, based on whether or not they have
vascular tissue.
1. Xylem transports _water___ & _minerals____ from the _root___ to the rest of the plant.
2. Phloem transports _”food” (glucose)___ from the _leaves_____ to the rest of the plant.
B. Plant Growth
1. Primary Growth – Lifelong growth occurs at the tips of the _stem____ and the end of the _roots_ in tissue called the
2. Secondary Growth – Trees and some other plants have a second type of meristem tissue; allows them to grow
in width or girth.
C. Roots
Roots _anchor the plant ___, absorb _water____ and _minerals_______ from the soil, and
transport these materials to the stem. Some plants also store food in their roots. Each root has root hairs, tiny
extensions of epidermal cells that increase _surface area______ for _water absorption_____.
D. Stems
Stems provide support for the plant. They contain _xylem___ to transport water & minerals and _phloem____
to transport nutrients.
E. Seeds
Not all plants produce seeds, but those that do have a tremendous reproductive advantage. A seed consists of an
_embryo____ surrounded by a tough protective coat.
1. Survival Advantages of Seeds
a. Protection
b. Nourishment - _Starch____ is stored in the seed for developing _embryo__________
c. Dispersal – Easily spread by _wind, animals, water_______; reduces competition for _nutrients___
d. Dormancy – Seeds remain dormant or _inactive_____ until conditions are _favorable_____.
2. Seed Germination
The first visible evidence that a seed is germinating is the emergence of the embryo's _root____,
followed by the growth of an embryonic shoot that develops into the plant's _stem_____.
E. Leaves
Leaves are the main organ for _photosynthesis_____. They have a large surface area for maximum
_light absorption___________. The structures of a leaf include:
A. Cuticle - _Waxy_____ covering to prevent _water loss_____
B. Epidermis – Outermost layer of cells; prevents _injury, infection_____
C. Mesophyll - _Photosynthetic______ layer of leaf
1. Palisade layer – Upper portion of mesophyll with closely packed cells; site of most _photosynthesis_____
2. Spongy layer – Underside of leaf; loosely-packed cells to allow for exchange of _CO2 and O2_____
D. Vein - _xylem___ + _phloem___
E. Stomata – Opening in underside of leaf that allows _ CO2_(carbon dioxide)_ to enter; _ O2_(oxygen)____ to exit.
F. Guard Cells – Control size of _stomata_____. Work to preserve balance between allowing for gas exchange
without losing too much _water__. “Plant sweat” is known as _transpiration___.
Plants are divided into two basic groups based on whether they contain _vascular____ tissue:
A. Bryophytes – No vascular tissue present (pp. 556-559)
Bryophytes, or _mosses____, are the only group of plants that lack vascular tissue. This limits both the _size______
and _location__________ of this group of plants. Mosses are _small____ and typically live in _moist_______
areas. In addition, a moist climate is required because mosses have _”swimming”_______ sperm. The sperm must
swim to the _egg__ cell in order for _fertilization_______ to take place.
B. Tracheophytes – Contain vascular tissue
(pp. 560 - 562)
Tracheophytes are vascular plants which allows them to _grow taller________ and
_live in drier climates___________________________.
The tracheophytes are further subdivided based on the presence or absence of pollen, seeds, and fruit:
1. Pterophytes – No pollen, no seeds, no fruits
Pterophytes are commonly called _ferns_______. Although ferns contain vascular tissue, they are still found
predominantly in moist climates because the sperm must _swim_____ to the egg cell.
2. Gymnosperms – Have pollen and seeds, no fruit
The word, “gymnosperm” means _”naked seed”___ because the seed is not protected by a _fruit______. A unique
characteristic of gymnosperms is the presence of _cones____. The largest group is the _conifers____ which
includes _pines, spruce, cedar________. Conifers have characteristic leaves called _needles___, which are
modified to _prevent water loss______ and _minimize ice build-up______________________. In
addition, gymnosperms (and angiosperms) have “flying sperm” or _pollen_____, so they are no longer tied
to _water____ for reproduction.
3. Angiosperms – Have pollen, seeds, and fruit
Angiosperms are the most complex and adaptable of all plant groups. They are also the most successful due to two
important modifications:
A. Fruit - A fruit is a mature _ovary___ that contains one or more seeds. It provides the embryo with greater
_protection______ and _protection_________ than found in gymnosperm seeds. The fruit also increases
seed dispersal because fruits are eaten by _animals____, seeds pass through _digestive tract______________
and are _eliminated____. Some fruits are not intended to be _edible_____.
B. Flower - The flower is the reproductive system of the angiosperm. It enhances _pollination__, which occurs
as a first step to fertilization.
1. The male reproductive organ is the _stamen____, which consists of the _anther________ and
_filament_______. _Pollen_____, is produced by the anther and contains the _sperm cells______.
2. The female reproductive organ is the _pistil____, which consists of the _stigma, style, and ovary__. Fertilization
of the _egg___ cell occurs in the _ovary____.
C. Types of Angiosperms – Angiosperms are further classified into two groups based on the characteristics shown below.
Monocots include plants such as _grasses, corn, lilies_____________________________. Dicots are more abundant
and include plants such as _roses, oak trees, etc______________________.