Pteridophyta: life cycle, ferns vs moss, sub classification Video Lecture - NEET

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now here so now with this idea about the
structure let us talk about the life
cycle of a terror to fight so here we
are talking about the life cycle of a
fun so which is the plant here plant is
the sporophyte so here if you see this
is the mature sporophyte so mature
sporophyte is nothing but the plant
itself so this is the these are the
phones now these phones with have
sporangium and the sporangium will
consist of the spores so here if you
look at this these are the leaf like
appendages between which sporangium are
present so these are the sporophylls the
leaf like structures are the spore of
its length so these are the sporophylls
and in this photo phil's are enclosed
small structures called sporangium so
this is the magnified image of a
sporangium inside this pod on Tiamat
present the spores so these pores are
released so what will happen the spores
will germinate the spores will germinate
to form the gametophyte so you see the
spores germinate to form gametophyte
this is the young gametophyte this is a
slightly mature gametophyte what is the
magnified that structure which produces
the gametes so now when this gametophyte
Metro's it will produce the male and the
female gametes so this portion of the
gametophyte is the antheridium
antheridium is the male gametophyte and
this portion of the Gabbin to fight is
the archegonium so this is the female
gametophyte so the male gametophyte will
produce the male gametes which are
spawns and the female gametophyte will
produce the female gamete which is n so
now this sperm and egg now the sperms
will come out from the male gametophyte
and it will come to the female
gametophyte now how will it come
identify the female able to fight by sea
here it is on the same plant so if it
isn't the same plant it can any based on
internal externally also it can be
carried away by many agents like air or
water so once it reaches the female
gametophyte the fertilization takes
place there is fusion between egg and
sperm happens inside the female
gametophyte so as a result as I got is
formed in the female gametophyte this is
I got then will gradually grow to form a
new sporophyte so gradually the
sporophyte will grow so here again if
you see this is the female gametophyte
so on top of the female gametophyte the
sporophyte is growing so sporophyte is
attached to the female gametophyte and
it is receiving its nutrition from the
gametophyte and then gradually when the
sporophyte matures we do not see the
gametophyte now and the plant which we
see as a terrified or as a fawn is
nothing but the sporophyte so this is
about the life cycle of a terrible fight
see all you need to understand is the
basic concept so basic concept of
reproduction is that you need gametes
for reproduction who will produce the
emits gametophyte
so from gametophyte damage will be
produced they will fuse they will
produce I got zygote will form the
sporophyte sporophyte will release the
spores the spores will again form the
gamete so this process is common to all
type of plants it is just that some
lunch will have some additional stages
for example in cases of for a case of
mosses we saw that additional step of
proto NEMA right now in case of these
phones we see that the sporophyte is the
dominant phase because yet the
sporophyte is the long-lived plant which
we actually see around us so here what
are the characteristics of the
sporophyte which makes it the dominant
phase so here the sporophyte is
multicellular the sporophyte is well
differentiated between roots stem and
leaves you see here roots leaves and
stem so it is when differentiated as
well moreover it is long lived so
sporophyte is
the dominant phase of the plant once we
have understood this now it is time to
talk about the gametophyte and the
sporophyte so let us look at the
distinction between a gametophyte
and a sporophyte in case of a fun so in
this case we saw that gametophyte was
small however multicellular mostly
photosynthetic palace so if you look at
the life cycle of the fern where do we
see the gametophyte is a small structure
it is multicellular and it is mostly
photosynthetic it it mostly has a green
colored pigment and it can perform
photosynthesis so this is often termed
as pro thalis so this gametophyte is
often known as roll palace when I talk
about sporophyte it is multicellular
well differentiated because of which the
sporophyte becomes the dominant phase in
case of a fun see why I am telling all
these things to you is that I want you
to judge yourself which phase is the
dominant phase in which plants life for
example if I talk about moss it is a
bryophyte so when you look at the
lifecycle of a graphite you your son
should be able to tell which phase is
dominant so what are the characteristics
of a phase 2 the dominant it should be
long lived it should be multicellular it
should be well differentiated so but in
case of a fun which is a terrible 5 we
saw that sporophyte is the dominant
phase so you will have to evaluate
yourself that which base is dominant and
why that phases dominant so let us have
a quick comparison between the life
cycle of a moss and a fun so we
discussed both of them right so moss
that is a bryophyte when you look at its
life cycle what happens here here the
gametophyte is the dominant phase so
these as the dominant phase but whereas
in case of a fern the sporophyte is
dominant phase so this is the fun and
this is must
so here gametophyte was the dominantly
so this was the long-lived plant which
we see but in this case purified is the
long-lived plant that we see so here
from gametophyte damaged were form the
male gametes and the female gametes and
they fuse together to form the zygote so
in this case from sporophyte spores were
formed and the spores germinate to form
the gametophyte and then from the
gametophyte the gametes are formed but
in this case the process goes in other
way round
first a zygote is formed and then from
this I got it will develop to form a
sporophyte yet here it the spores
develop to form a gametophyte right so
here sporophyte is the intermediate
phase whereas here in this case
gametophyte is the intermediate phase
now the sporophyte in case of moss will
then give rise to spores which will
germinate to form the gamma 2 fights
back in this case this gametophyte will
form the garvik gametes which will
fertilize to form back the sporophyte
right so you now understand both the
life cycles that how the life cycle
changes if your dominant phase changes
from a gametophyte to a sporophyte clear
ok so with this I think that I have been
able to explain you the characteristics
and the behavior of
pteridophytes and bio finds now we will
look at the plant types of pteridophytes
based upon the type of gametes which
they produce now the further if they are
divided into two types first is hormoz
porous and the other one is
heterosporous for most photos homo means
same so if the square and G are produced
similar spores the spores which are
produced by the sporangia
they are similar then they are known as
homo spores so example of homos porous
would be in fact most of the third
fights alchemist pours so ferns are also
homo swallows because the spores
produced by this for a fight are all
similar whereas the other type of plant
is hetero spores so here
the spores which are produced are not
similar so some spores are smaller in
size whereas the other sports are larger
in size so megaspores are those which
are larger in size and microspores are
those which are smaller in size now
these large sports that is the mega
spores these spores germinate to form
the female gametophyte whereas the small
microscope micro spores germinate to
form the male gametophyte so two types
of sports will be font larger spores and
smaller spores larger spores will
germinate it will form female
gametophyte smaller spore sense I'll
finish it with four male gametophyte and
then this female gametophyte will
produce the pineal Gammons the male
gametophyte will produce the male gamete
and then the female and male gametes
will fuse together to form the zygote
right so there are there are some
pteridophytes which are also
heterosporous in nature so examples of
heterosporous plants are selection Ella
and salvinia so now here you see this
plant if you compare the phones with the
selection Ella do you see the difference
in the size of the leaves in phones you
actually have bigger games but in case
of selection Ella you really have
smaller needs so that's what I was
telling you sometime back right that
some pteridophytes have big leaves by
others have smaller leaves so
selaginella and Sylvania
are some plants which produce two types
of sports two varieties of suppose one
bigger one and other smaller one so on
the basis of the type of spores which
are produced by the pteridophytes
they are classified into homos porters
and heterosporous plants so now even in
pteridophytes there was a further
classification done based on some
similarities and differences so
pteridophytes
classified into four groups see low
slopes ada like cops ada spin-offs Ada
and Tirat sitter so these were the four
classes into which there is no fights
well classified
however we will not get into the details
of these glasses so that you will study
in your higher classes so for now we
will end our discussion on pteridophytes
and we will move on
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