KINGDOM III. The
The angiosperms are the plants with flowers and fruits, which means
they are the most complex plants that exist. Thanks to that they are the
ones with the most possibilities to survive. They already constitute
2/3 of all species of plants that exist. Theirs advantages over Gymnosperms
Generally the pollination is done by insects that go from flower
to flower and this is a more efficient way than pollination by wind.
The fertilization and forming of seed happens much faster, and does
not require a couple of years such as the pines.
The seed dispersal is more effective because they are inside the fruits.
There are fruits that are eaten by animals which causes that seeds
are being excretioned far from their progenitores, therefore far from
their shadows which could make it more difficult for them to grow. Other
fruits, such as coconut, float in the water and can overcross seas, other
fruits have hooks to get tangled in the hair or feathers of animals, etc..
The germination of the seeds is much faster. For example, there
are plants in high mountain that are born, reproduce and die leaving seeds
for the next year, all this in just few weeks when there is no snow.
of this makes the Angiosperms the most interesting group of all plants.
Activities to do. Read the explanations on the general characteristics
and classification of plants and perform Multiple Choice Test 15.1 and
Relate pictures with names 15.1. Then read the text on Angiospermes and
perform Multiple Choice Test 15.2, Relate pictures with names 15.2 and
1. The Angiosperms. They are the plants
that have flowers and fruits, so they have theirs seeds enclosed
in fruits. The flowers are formed by a series of modified leaves and they
can distinguish the following parts:
1. Flower pedicel.
It is the area that connects the flower to the stem. The flower pedicel
ends floral receptacle which is an enlarging from where the other
parts of flower sprout.
It is the set of a small green leaves, called sepals, which are
at the base of the flower.
It is the set of leaves that usually have very bright or white colors,
called petals. The vivid color is easily detectable by diurnal
insects and white by nocturnal insects. Also, many times they emit smells
to facilitate its detection and in its base secrete a sugary substance
called nectar, such as the pollen, which provides food for many
insects. This induces the visits of insects and therefore the transmission
of pollen from one flower to another, meaning the insect pollination.
It is the male part of the flower. It is formed by a set of filaments
called stamens. In each stamen there can be distinguished one
filament and two final enlargements called teaks. Inside
the teak there are pollen sacs in which pollen grains
It is the female part of the flower. It is formed by one or more structures
in the shape of called long-necked bottle pistils. Each pistil
is formed by one or more modified leaves that are called carpels. In
a pestle can be distinguished three parts: the enlarged base or ovarian,
neck or style and the mouth or stigma which have a plurality of hair
that help setting pollen grains when they fall on them. Inside the ovary
there are one or more formations called eggs, inside of which
the female gametes or oospheres are located.
pictures with names
2. The biological cycle of the Angiospermes.
grain that is attached to the stigma generates a long tube called
a pollen tube that runs through the style up to an ovule.
the fall the male gamete joins oosphere (fertilization)
and forms a cell called a zygote.
multiplication, generates an embryo, and together with the rest,
also transformed from the egg, constitutes the seed.
the seed, ovary walls fatten and transform into different layers
of the fruit. If
they are tender they are called fleshy fruits. For example apple,
peach, grape, orange or melon. If walls are not fleshy, they are called
dried fruits. For example, sunflower, wheat, acorn, pea and bean.
3. Types of the Angiospermes. There are two types, which are:
- The Monocotyledons.
Are those that have seeds with one cotyledon.
- The Dicotyledons.
Are those that have seeds with two cotyledons.
By the evolution,
the monocotyledons are the most recent, but already have three times more
species than the dicotyledons species. Its distinguishing features are:
|The embryos have
only one cotyledon
||The embryos have
roots, meaning that all of them raise in the same place and form
meaning that there is one main root from which secondary roots sprout
|The leaves are
layered, long, without the petiole and the nerves are generally
||The leaves are
layered, have a great variety of shapes and the nerves are not
|Have 3 or
||Have 4 or
banana and wheat
almond and oak
pictures with names