a robotic my name is Jason want crime a
science coordinator with the national math and science initiative and
this screencast the second in a series on body help us get ready for the AP
Biology exam
and we're gonna center this one around growth and development up
plans so pleasurable to grow throughout their lifetime to the presence of on
differentiated tissues cock mere steps now
we look at this work on differentiated we are reminded up to the home
stem cells within our bodies they're not
nerve cells they're not muscle cells are not skin cells that type thing
there undifferentiated K and if we remember
a.m. from the the last screencast we talked about
that boss sales within a planet or depot
which means that they have the ability to take on the characteristics up
other differentiated cells within that plan
so if it needs to be a rude it can be a rude needs to be estimate can be a stem
that type thing
K to mir stems that we're going to
concern ourselves with are a pickle in lateral
mare steps apical meristems are going to give the plant primary growth
they're gonna cause a a the stem in the route to grow
longer they're gonna give it link K and they're located at that tips
and lateral meristems are going to add
secondary growth and they're gonna crop they're gonna cause that plan to
increase in ger
or with K to list if I
if I have a tree am now to grant K
now your limited
you put a nail
rare game and I'm gonna wait twenty five years
in 25 years
I'm gonna get all kinds growth
hopefully K this thing is going to grow
gonna flourish now we ask ourselves
where is that nail actually five years
apical meristems where
are those eight comair steps their tips
right so
we're gonna it right where we left
right there it's not
up here somewhere right that cuz the growth isn't occurring from down here
awesome are on now a fuck about lateral meristems because
if this like an oak tree or something like that we get that secondary growth
that male might that nail might be
inside that bark might be inside that secondary
as I'll K have you ever at seen those things
up basically they sell them to put on your tree like nail into your treat them
like all
eyes and mouth and after a few years that secondary girls will actually
group over those eyes like around that mouth and actor looks like a
sup face on my tree so
of talk about reproduction in and just berms
specifically right so this
is a in that mean the flower let its prior knowledge but we're gonna do a
a quick brief review here this idealized flower has mail structures
add called the stamen which compose a both an anther
and filming Panthers aside a pollen production so what do you think this
filament is doing we look at look at that evolutionary
in advance so that film it gives K you got a pollinator that's coming along
and landing on this flower right will get that answer is way down there by
by the receptacle K down here
nussle next to the ovary the chance
love that be or humming bird or whatever Kenya that pollen on it today in Goa
pollinate another flower
Carlisle booklet film it does just kinda
Chris since that day after I helped right was look at the female part plan
call the carpels
sometimes called the pistol PI stil
K you the stigma style
and the have the over it K
so your member alternation generations this what it looks like
inside a an angiosperm K
the slots open and the sperm it's a great overview the reproductive process
so again just remind you you do not have to memorize
a any particular I am
life cycle I E alternation generation surveying the four different types
plants but just understand the
basic concept up this alternation between ap lit
and deploy K and what we see here is that for all stations going to occur
when a male gametes
for lies with the female can meet for the plan in Brea
now at that point this I go is now deployed
right are sperm and egg where haploid K
now the next three flights are going to cover a concept called double
fertilization
this is this double fertilization is unique to and just berms
K though the details us have particular
reproductive cycles up plants and animals are no longer specifically
covered on AP Biology exam
don't furloughs they should it's so crucial to the evolutionary success
banyas firms that we must visit handout
discussion for that for the exam so
here we have and the carpal or the pistol k have to
you had the stigma style and over and we can see polar nuclei
in here and we can see the heck K so
if the the pollen tube
at it it does pollen grain basically germinate its gonna grow this
its gonna start growing much ha likely downers Grove's pollen to man I want you
to pay special attention
to these two sperm their comment down with their K
the pilot who is going to discharge the two sperm
into this female comida fight
to called the embryo sac within this article
okay
and I basically one sperm is gonna
fertilize the egg which forms the psycho the other sperm combines with
the two polar nuclei at the embryo sacs large central cell
forming a triploid cell this going to develop into new trick tip tissue called
endosperm
now these two advance comprise what we called double
for Liz X you fertilize as I go and you've combined
that that other sperm with the two polar nuclei making endosperm
K this is double fertilization and in despair unique
inches per now we think about me at
in the spar it is im a very important component up
our human diet worldwide frances was take wheat
for example the in the sperm is
adequate its then offered to selectively take now
in in in the process in this third call it white flower
K the embryo itself which we called churn
the seed coat which we call brain are removed
K now if you right now to keep the embryo in a Seco
the German the brain you keep those in there now we call that whole wheat
right some other examples a vendor sperm would be the mail
or the meat quote-unquote in a coconut
also the nutritive tissue inside up
corn kernels thats endosperm swell
discuss the coevolution at these pollinators
and flowers K
so these pollinators are
flower specific
K these pollinators and will
only pollinate certain types of plants which have certain types of lower
the flowers are going to evolve along with these pollinators
just bored us some examples butterfly celo
the supply was the pollinator yellow months
are out most frequently it not so therefore they pollinate white flowers
that are fragrant
BC yellow blue and you be like the flower the colony are yellow or blue and
you can see that UV radiation
hummingbirds need a lot of sugar and I see red
they pollinate flowers that are red and usually have these
significant neck to reserves K bassam possums are nocturnal
and pollinate flowers that are frequent and attract and sex
K the pollinators and flowers
have Cullowhee volved together well thank
a a specific example I'll this
relationship present the California Buckeye tree is pollinated
only by native California honey bees that are immune to the neurotoxin found
in the park
other honey bees are sensitive to the spa
K so in so on so only these California honey bees
are munis nor talk to so they're able to actually
am pollinate victory the flowers on a tree
some work is actually resemble in sex all-male
in sex will come along no actually trying to mate with these workers
in the fact they are actually involved in the pollination
up these flowers Rai
so here goes: look at the structure from a church seed
okay you see a seed coat you see
I am other structures within that basically associated with
endosperm the different parts so a
the embryo your first seed leaf at your first route
that type thing K a/c consists a big dormant plant in Brea
okay it's surrounded by its food supply the cotyledons the endosperm
for both the CD surrounded by his heart protective Seco
K dormancy describes appeared when the embryo within a seed
stopped growing and metabolism nearly ceases
this inning any n adaptation for tough times
well that the drought or freezing winters that type thing
certain environmental conditions can trigger the seed to break this dormancy
now support time in a seed germination
and its reliance on both temperature and water are
specifically tested on AP Biology exam
there's two types germination K germination begins with ambition
the up take up water by a dry see
rupturing a seed coat triggers metabolic changes that allow the plant embryo to
resume
growth now the time to see germination
and its reliance on temperature water again
just to point out these are specifically tested on AP Biology exam
K low water potential the sea triggers this
ambition K in common
in a here we see a common garden beads
the season common garden beats K straight bi other hook on the hypocotyl
poll the cotyledon from the soil
K in maize in other grasses that we see down here and be
the shoot grow straight up through the tube %uh coli alkyl
K breaking dormancy is a phenomenon
attributed to enzymes and hormones with the end the seats
the essential seed late anatomy terms are cotyledon
endosperm and radical so
do dry seed perspire yes
well unless they've been suffocated in a plastic bag or become completely
dehydrated
finally just look at some adaptations for seed dispersal
K how did the scenes get out into
how they propagated out away from
the mother plant right and again
you wouldn't need to memorize all these but be able to discuss
one yr a few right so first we see over here
somewhat are wind like a
just bars like milkweed alright Danny Leiner maple
you've probably seen these little helicopter guys
coming down to the ground right maybe they're propagated by animals we have
bigger texas-san burgers
and Blackberry these things have some
should spines on then they're gonna be able to just stick
to animals that are walking by right they're going to basically go dispersed
that somewhere else
even by water you see a lotus cat tail
even coconut well we actually what most people think is the coca is actually the
sea dry
and so that's within this big hairy fruit
and that's going to be able to just bob up and down and the waves until it lands
on
some ground and then be able to
to grow from there some
flowers just burst open K like a violator which case large jewelry
right burst open the cecal fly right
some of them I A would put the CD in these
at these fruits that humans like likely collect beans
and wheat alright in cheers these things have seeds
unless we genetically take I'll obviously
but but know we can disperse that we can do that
again please make sure that you got through
the S Hannah this screencast of being cast as many times as you need to
stop take some notes ask some questions ask your teacher
and um I'm really do believe that this can help you with them
growth and development specifically the angiosperms
on AP Biology exam