Biodiversity
is the term used to describe the variety of life found on Earth, it includes
ecosystems, genetic and cultural species. Regarding the Flora diversity in
forest zones, seedless and seed-bearing plants can be found. The main
difference between seedless plants and seed-bearing plants is their methods of
reproduction. As their
names imply, seed plants produce seeds using sexual reproduction, and seedless
plants do not.
Could
and warm humid forest have a rich and varied climate conditions. For example,
the cloud forest has exuberant and unique vegetation with plants that derive moisture and nutrients
from the air and rain, and usually grows on another plant. This kind of plants
are called epiphytes and some of them are:
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Heliconias | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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Orchideas | | | | | | | | | | | | | | | | | | | | |
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Bromeliads |
Additionally,
a large quantity of mosses, ferns, arborescent ferns, and lichens can also be
found in the cloud forest.
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Ferns |
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Arborescent ferns |
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Mosses |
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Linches |
In
general, these humid forests house plants without seeds, which due to their
morphological and functional characteristics maintain solid humidity. Seedless plants are classified in Bryophytes and Pteridophytes.
Bryophytes:
They are also known as
nonvascular land plants. They are small
simple plants, with no flowers, fruits or vascular systems. They have rhizoids
(which are similar to roots), stalks, and leaves, and a capsule with spores for
reproduction. Bryophytes
exist in a wide variety of habitats, they can be found growing in a range of
temperatures from cold arctic to hot deserts, elevations from sea-level to
alpine, and moisture such as dry deserts and wet rainforests. Bryophytes can
grow where vascularized plants cannot because they do not depend on roots for
an uptake of nutrients from soil. Bryophytes can survive on rocks and bare
soil. They also need much water to survive. There are three types of
bryophytes:
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Liverworts |
Characterized by a thalloid gametophyte or
sometimes an upright leafy gametophyte that resembles a moss.
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Hornworts |
It is a
genus of rootless thin-stemmed aquatic monoecious herbs with female flowers having a single
carpel.
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Mossess |
Characterized
by a gametophyte having a small leafy often tufted stem bearing sex organs at
its tip; it is also a clump or sward of these plants.
Bryophytes
typically measure one to two centimetres tall. The same as all land plants,
bryophytes have five life cycles with alternation of generations. In each cycle
each of its cells contains a fixed number of unpaired chromosomes, alternates
with a diploid sporophyte, whose cell contains two sets of paired chromosomes.
Gametophytes produce haploid sperm and eggs which fuse to form diploid zygotes
that grow into sporophytes. Sporophytes produce haploid spores by meiosis that
grow into gametophytes. Liverworts,
mosses and hornworts spend most of their lives as gametophytes.
Pteridophytes:
These
are middle-sized plants with vascular systems but with no flowers or fruits. Ferns have rhizomes, and
compound leaves called fronds. During reproduction, the underside of fronds
release spores rather than seeds, they include the highly diverse true ferns and other
graceful, primarily forest-dwelling plants. There are about eleven thousand
different species of pteridophytes, making them the most diverse land plants
after the flowering plants (angiosperms). Pteridophytes may represent the
closest living relatives (sister group) to the seed plants. Pteridophytes have
been divided into three classes namely Lycopodophyta (club mosses), Sphenophyta
(horse tails) and Filicinophyta (ferns).
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Lycopodophyta |
The spores of Lycopodiophyta are highly flammable
and so have been used in fireworks. It
is also under investigation as a possible treatment for Alzheimer's disease.
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Sphenophyta |
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It is a division represented by a single living genus
(Equisetum). It has a
worldwide distribution but occurs in greater variety in the Northern
Hemisphere.
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Filicinophyta |
There is a characteristic uncurling of the young leaves as they expand
into the adult form. Reproduction is by means of spores borne on the underside
of specialized leaves.
Seed-bearing plants are varied and widely
distributed at different climatic levels. They are an important part of forest,
from mangroves, at 100 meters above sea level, up to the herbaceous moorlands,
between 2.440 and 4.000 meters above sea level. Seed-bearing plants are
classified in Gymnosperms and Angiosperms.
This is
the oldest group of vascular plants with flowers and bare seeds which are not
considered fruit. These plants are also called conifers because their flowers group together in the form of pines
or cones. There are male cones that produce pollen, and female cones that
contain ovules. Upon segmentation female cones form seeds that are found
between the scales of the cones. Most gymnosperms are trees and bushes, such as
pine, cypress, and Podocarpus which found in the Andes Mountains and is one of the
endemic species of Ecuador. Gymnosperms are classified in:
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Cycadidae |
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Gynkgidae |
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Gnetidae |
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Pinidae |
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Cupressales |
Angiosperms:
This is
the most abundant and diverse group of plants on the planet, they are found in
all types of ecosystems. Angiosperms have vascular systems, flowers, and
fruits. They can be plants, brushes, or trees. Some examples include poppy
flowers, roses, olive trees, and thyme, oak, and walnut trees. The modern
classifications of angiosperms is: Basal angiosperms and Core angiosperms.
Basal
angiosperms are subdivided in Amborella,
Nymphaeales, and Austrobaileyales.
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Amborella |
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Nymphaeales |
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Austrobaileyales |
Core angiosperms are subdivided in:
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Chloranthales |
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Magnoliids |
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Monocots |
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Eudicots |
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Ceratophyllum |