Download LESSON 10 PLANTS The plant kingdom. Plants originated as part of

LESSON 10
PLANTS
The plant kingdom.
Plants originated as part of a group of green algae
approximately 500 million years ago. They were
the first living beings to colonize the Earth.
Plants are multi-cellular(eucariotyc)living beings
that create their own organic material through the
process known as photosynthesis, the reason they
are known as autotrophs.
Bryiphytes.
These plants, then, are incapable of remaining
erect so they tend to be small and develop
close to the ground and are characterized by
living in humid, shady environments.
These plants don't have root, stem and leaves.
(Thallophytes)
Liverworts: non-vascular conduicts, the cells
absorb water and substances that they need
directly from the ground and they pass from
cell to cell through diffusion.
Pteridophytes.(Cormophytes)
Ferns: have woody vascular conduicts.
They have roots, stems and leaves but lack
flowers and seeds.
Ferns live in humid and shady areas. In general,
these plants do not grow taller than 1.5m,
although in some tropical areas some
specimens can reach several meters.
The classification of plants.
a) Plants without flowers.(Cryptogams)
Bryiphytes.(Thallophytes)
Liverworts: non-vascular
Mosses: don't have woody vascular
conduicts.
Pteridophytes.(Cormophytes)
Ferns: have woody vascular conduicts.
b) Flowering plantas.(Phanerogams)
Spermatophytes.
Angiosperms: with ovary and fruit.
Gymnosperms: without fruit.
Mosses: don't have woody vascular conduicts.
And have three parts: axis (similar to a stem),
phylloides (similar to leaves) and rhizoids
(similar to roots).
b) Flowering plantas.(Phanerogams).Plants with
isolated in the stem, but formed groups that are
flowers
called inflorescences.
Spermatophytes.
Plants with flowers, or Spermophytes, reproduce Fruit and Seeds.
though seeds that form a special organism: the
Angiosperms are characterized as such because
flower.
they produce fruit, bodies from the ovary of the
Angiosperms.
flower that can contain one or many seeds.
Angiosperms are the newest type of plants.
The Flower
The flower is the reproductive organ of
angiosperms. In flowers there are four different
types of leaves: sepals, petals, carpels and
stamens.
Gymnosperms.
Gynmosperms appeared before angiosperms,
about 300 million years ago. Their most
representative characteristics are:
a) All are woody plants.
b) In a large number of species, the leaves are
narrow, in the form of a needle (like pines)
or a flake (like cypresses), and tend to be
perennial.
c) The flowers are always unisexual: there are
male flowers and female flowers.
d) They do not have fruit but rather the seed
appears bare.
Fruits are characterized as fleshy (like a tomato
or peach), when the part surrounding the seed
is a juicy mass and dry (like a sunflower seed
or nuts) if the seed is surrounded by a hardened
structure.
Fruit makes possible the dispersion of the
seeds.
Flowers that have all four types of leaves are
called complete.Some flowers do not have
calyx or corolla and it is then said that they are
naked. When the same flower presents stamen
and carpels, the flower is considered a
hermaphrodite. Those that only have stamen
are male flowers and those that only possess
carpels are female. In general, flowers are not
Pine
Cypress
Conifers
Inside of the gymnosperms, the largest and
best known group is the conifers, which
includes pines and firs.
The flowers of the conifers lack petal and
sepals and are unisexual. The female
inflorescences are called pine cones.
Conifers do not form fruit.
Functions of the root
Roots have two principle functions:
a) Fix the plant to the ground.
b) Absorb water through the absorbent hairs
and take in minerals that constitute the raw
sap.
Types of roots
There are three types of roots.
1.Tap Root :
a) These show a principle root, from which
grow various lateral axis or secondary roots.
It is characteristic of bean.
b) This is formed by a very thick principle
root which accumulates reserve substances.
The stem.
The general structure of spermatophytes.
The structure of all spermatophyte plants present
three basic parts: roots, stems and leaves.
The root.
The root is the part of the plant that grows
in the opposite direction of the stem and,
in general, is underground.
Parts of the root:
This is the case in the root of a carrot.
2. Fibrous root: In these there is no distinction
between the principle root and the secondary
roots, they have the same thickness and
localize it as a tuft of hair, like the root of an
onion.
3. Adventitious root: ooriginated from stem,
branches or leaves
The stem is the axis of the plant, thanks to
which it maintains rigidness. It also serves to
support the leaves and flowers and connects
the leaves with the roots.
Parts of the stem:
In the principle axis nodes are distinguished
which connect the leaves and branches to it.
The space between two nodes is called the
a) Duration: They are annuals if they grow for
internode.
one year, or perennials if they grow for two or
Buds are the growth on the stem that allow this
more years.
development. They can be terminal, responsible
b) Consistency: They are non-woody if they are
for the growth in length of the stem, and auxiliary,
soft and woody if they are tough and not
when branches grow.
green.
c) Distance from the ground.
The aerials are the most common; normally
they are erect like that of a pine tree or a
palm tree, but they can also be a climber like
in the case of the stem of ivy.
The aquatics develop close to water, for
example, those seen in water lilies.
The underground grow underground and can
be thick because they accumulate reserve
substances. Onion.
The stem is the axis of the plant that supports the
leaves and the flowers and also provides
transportation of the sap between the leaves and
the root.
Types of stems:
Stems can be classified with the following three
characteristics:
Leaves.
Leaves are expansions in the form of a plate,
generally green in color, that grow from the
trunk or the stems of a plant.
Parts of the leaf:
In the drawing of the leaf you can see:
a) The blade, or flat part of the leaf.
b) The upper face of the leaf, called the top
part, and the lower face, underside or bottom,
which is crossed by veins, that are the vessels
where raw sap and sap are transported.
c) The petiole, the corner where the leaf joins
the stem.
Functions: photosynthesis is done in the leaves.
At the same time, the plants regulate the quantity
of water that reaches the whole plant through
transpiration, the mechanism of elimination of
water in the form of vapor. This loss of water is
produced during the day through the stomas, holes
that are found on the underside of the leaves.
Types of leaves:
The same as with stems, classification of leaves
can be made using distinct criteria:
a) Type of venation. If the leaves have only one
central vein, like those of a pine, it is said that
they are single; if they present a principle vein
that is separate from several secondary veins,
the nervation is pinnate; if at the same point of
the principle vein there are other secondary
veins that are of the same importance it is said
that the nervation is webbed; if the top side
has parallel veins running from one end of the
leaf to the other, the nervation is parallel.
b) Shape of the blade. Leaves can be simple
when the blade is complete, that is to say that it
is in one piece, and compound, if the blade is
divided into pieces called leaflets.
Simple leaves can have the form of a needle,
lanceolate (lance), oval, heart-shaped,
elliptical, sagittate (like the point of an arrow)
etc.
c) The margin of the blade: entire, serrate,
dentate, lobed, sinuate, cleft, etc
SHAPE
MARGIN
VENATION