A. Fertilization & Development Occurs in both Plants and Animals

What is the name of this diagrammed process in which the
daughter cells (all four of those pretty ones on the bottom) each contain only half the number of chromosomes of the former
mother cell? This was covered recently in class.
(Ref. #1) ________________

Ref. #1

A.1. Fertilization may occur directly _______ (before or after) the process pictured in Ref. #1.

In A 1 (above), why did the teacher have to say may and not does? ____________________________________________________________________

Ref. #2 Ref. #3 Ref. #4

2. The ______ (Ref. #2) (a male gamete -- let's mathematically call it 'n') +
the ______ (Ref. #3) (a female gamete -- let's also call it 'n') unite following
the process of (Ref. #4) F_____________ to form a
_______ (Ref. #5) (algebraic term) cell known as a Z _ _ _ _ E. (Ref. #6)

Ref. #5 Ref. #6

Please click here to see the answers to this set.

B. Fertilization & Development In Plants only

1. In fertilization within a flower, the chamber (green) surrounding the embryo
(the ovule) differentiates to become a S _ _ _ (See Ref. #7)

An Ovule & surrounding tissues (Ref. #7)

     Another Ovule Ref. #8
    (Note four ovules within a single ovary
    are sketched!)

Ref. #9 Ovule from a pine tree

Within which larger structure does the future seed (ovule) reside? ___________
(Consult above Ref. #8 above)

2. The whole area where fertilization took place (the ovary) soon ripens, often gets thicker, often stores starches and sugars and eventually differentiates into something we love to eat (a F _ _ _ _ )

3. Some of your teacher's favorite fruits follow. Name each! Some will surprise you that they are even fruits. The biological definition of a fruit
and the definition from the produce section of your local supermarket differ.

Ref. #10 A seedless _________________

Ref. #11 ________________ to
make a muffin

Ref. #13 _________________ for
Halloween or Thanksgiving pies.

Ref. #14 _________ on the cob

All of these are really fruits because they developed from a(n)
O _ _ _ _ which is the base of the flower.

Please click here to see the answers to this set.

C.   Fertilization & Development In Animals
       only
      (See also Video Disk Bio Science ovum 22371, Ovum + sperm 22373-9, and
      fertilization 22381-3 if your teacher has these available for an alternate presentation.)

1. Biological C _ E _ V A _ _ (it means splitting) is from
same root word as this (Ref. #15) butcher's tool
known as a C _ _ A _ _ R
Ref. #15

Cleavage is a special event following asexual cell division (M _ _ O _ _ S) in which cells divide to form new daughter cells, but they do NOT then G _ _ _ . (They do not enter _____ PHASE) After each cell division, each daughter cell must therefore be _ M _ _ _ E R in size than in the previous generation.(Ref. #16)
(Your teacher could not find the perfect diagram which accurately shows
the change in size between the mother cell and the two daughter cells.)

The two daughter cells should each be only
H _ _ _ the size of the original mother cell,
but this diagram set does not accurately show this size reduction.

Ref. #16

     The following video clip shows early cleavage divisions in a human embryo.
            Direct link to early human cleavage video on BOCES   server

The size of each daughter cell after the first cleavage division is only ONE   H _ _ _
(5-15 seconds into the video) of the size of the former mother cell.   After the second cleavage division (about 24 seconds into the video), each daughter cell is now ONE   _ _ A _ T _ _
of the size of the former mother cell.

      Of course, since cleavage is a form of M I _ O _ _ _, all the daughter cells are genetically
I _ E _ T _ C _ L to each other (and the former M _ _ _ _ R).  You might even say that in
the word Mitosis, the second letter which is an ___ signals that the daughter cells are
I _ _ _ T _ _ A _   to each other.

(A special mitotic (mitosis) blessing for the recently departed mother cell follows!)

"Dearly beloved former mother cell, may you now rest in pieces"

a. If during early cleavage ... (See captions next to the diagram!)

      a.       If during early cleavage and
       before cells start to become
       different (the process of
   D _ F _ E _ _ N T _ _ T _ O _ ),
        (Ref. #17) the dividing
        embryonic mass separates into
        two masses, ___________
        twins (Ref. #18) are produced.

Ref. #17

These twins (Ref. #18) resulted from an original
___ egg(s) + ___ sperm

Ref. 18

            b.      The other more common kind of twins
             (F _ _ _ _ _ _ _ L) (Ref. 19) resulted
             from ___ egg(s) + ___ sperm
             (Notice that one is a girl and one a boy!)

Ref. 19

Please click here to see the answers to this set.

Cleavage stages in a representative
animal species -- the Sea Urchin

2. (Possibly see also Bio Science disk starting @ 3630)

You're now asking "What's a sea urchin?" (Ref. 20)

This good looker is a red Sea Urchin! (but not necessarily an urchin from the red sea!)

Let's first see fertilization of an urchin egg? This is sexual reproduction at a very simple
level. We sure hope this urchin is not offended by being referred to as a simple creature.

The following video clip shows fertilization & early development in an urchin..

        Direct Link to silent video on urchin fertilization on BOCES server
It is there, but may take a full minute to load; at least it did for me at home on 12/31/07.
                                        OR
Link to silent video on urchin development at original URL
                                        OR

In the early part of this video you see two urchin eggs. The urchin sperm are hard to view. As soon as the sperm penetrates the egg, the egg stops any other sperm from entering. Pretty cleaver for an egg, don't you think? The egg then creates a chemical shield on the outside of itself. This shield is the F _ R _ I _ _ _ A _ _ _N   MEMBRANE that appears very early in the video on both cells. You also see many disappointed sperm "dancing" just outside this barrier membrane.

Do you now want to see some of "Urchie's" baby pictures? Here they are!

Six cleavage stages in the life of a very young Sea Urchin (Ref. 21)

      Here's a geometric doubling series, you may soon need: (If you are into computer
      operations, these numbers will be most familiar to you already!)
      1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048

      a.     In stage "A" just after F _ _ _ I _ _ Z _ _ _ O _, there is/are _____ cell(s).
        b.    After one cell division (by M _ _ _ _ _ _) at "B", there are now ___ cells.
        c.     After two cell divisions at "C", there are now ____ cells.
        d.     After about four cell divisions at "D", there are now about ____ cells.
                (They are all blended into each other, so this is very difficult to count!)
        e.     After about six cell divisions at "E", there are now about ____ cells.
        f.     After about eight cell divisions at "F", there are now about ____ cells.
                (The cells are all at the edges of the egg mass, but each cell is now too small to see!)

        Following are some classical steps of the continuous early embryonic life of organisms.
        Remember that cleavage is a continuous process, but we can still study stills. It's like
        watching a slow motion replay of a sporting event. The event took place in real time,
        but we are free to study and analyze the individual steps from a continuous play.

a.       Morula (similar to stages D & E above) (stage looks like a “bunch of G _ A P _ S”)
       (See also Bio Sci. Disk. #4600)
       But Sea Urchins seem to skip the morula stage of development and move directly
       into the blastula stage..

b. Blastula stage "end of E" & "F" above (about ____ - ____ cells) looks like a
“H _ _ L O _ ball of cells” (See also Bio Sci Disk #5174)

c. Gastrula stage (after "F") in which cell tissue L _ Y _ _ S start to form and
the “start of D _ F _ E _ E _ T _ A _ _ _ N” (See also Bio Sci Disk #22395-97)

Here's are two stills of a forming Sea Urchin Gastrula.

Early Gastrula (B & W) Ref. 22 Middle Gastrula (color) Ref. 23

Now let's see if we can find a video on complete early development of this urchin.

    You will see all the developmental _ L _ A V A _ _ steps after fertilization listed above and
     beyond. Near the end, you will see activity in which part of the cell layer of the Blastula rotates
     inward creating new tissue layers. This is the end of cleavage, which means that now after
     mitosis, the daughter cells will at long last start to   G _ _ _.    The tissues that form will now
     start to take on individual different characteristics. This is the beginning of
     D _ _ F _ _ E N _ _ A _ _ O _ .

     The following silent third video clip shows fertilization through gastrula stage also in an urchin..

Here is a direct link to silent urchin video on BOCES server.
Speaking of s - l - o - w; this beast took nearly 2 minutes to load/play; I may not make it to
New Year's Eve celebrations in time.

                                        OR
Link to silent video on more urchin development at original URL
                                        OR
If neither of the direct link worked, then please open your internet browser (the big e!) copy the web address (URL) below and then paste it into the browser.

http://video.yahoo.com/video/play?p=%22sea+urchin%22+&toggle=1&cop=&ei=UTF-8&b=0&oid=a4cd7a3f02f777a0&rurl=bsc2011-02.sp04.fsu.edu&vdone=http%3A%2F%2Fvideo.yahoo.com%2Fsearch%2Fvideo%3Fp%3D%2522sea%2Burchin%2522%2B%26toggle%3D1%26cop%3D%26ei%3DUTF-8

Here's a summary diagram of the early life of the Sea Urchin.(Ref. 24)

    This is what you also saw in the video.

    Firstly, an egg was fertilized and a M _ _ _ R _ N _
    developed around it.

    Then, the egg underwent _ L _ A _ A G _ in which
    the number of cells _ _ CREASED, while the
    average size of each cell _ _ CREASED.

    Finally, T _ _ _ U _ layers started to form as the
    early embryo entered the G _ _ _ R _ _ A stage of
    its development. .

Click here to see the answers to this section!

Bio H (and curious Bio R students) should continue on from this point.
For others, you are done with this activity. Sorry!

     Some of you are now wondering "What's so special about sea urchins?" Is your teacher stuck on them because of all the spines? Are sea urchins about
to rule the earth?   For all you urchin lovers who want to move on, here is a
good source to more videos on early development in more advanced creatures. As before, you may either hopefully play them directly from this site or alternatively copy and paste the URL's into a web browser.

Here's the direct link to the amphibian video. Frog #1 video link

Here is the less direct link to the amphibian video. Frog #2 video link

If that did not work do the following

Once you are on PowerMediaPlus.com, use their internal search for
"Amphibian development." Remember that you should have set up a PMP.com account with account name and password earlier this year. The hit that is just
over 12 minutes in length is our froggy baby. The key developmental sequences
lie between 6:05 & 8:50. Use the scroll bar to select this section of the video.
The parts after 8:50 are also very good. The frames just ahead of 6:05 are on mitosis in froggy, but you hopped all over this data already. Remember that this video may have to be buffered (pre-loaded I think) to be played. This might take
over a minute, so please have some fabulous patience.

3. Subsequent growth of groups of similar cells (known as T _ _ _ _ E layers)

The E _ _ _ D _ _ M (Ref. #25) comes from the outer tissue layer of the gastrula.

The M _ S O _ _ R _ (Ref. #26) comes from the middle tissue layer of the gastrula.

The E _ D _ _ E _ M (Ref. #27) comes from the inner tissue layer of the gastrula.

Ref. #25 Ref. #26 Ref. #27

a. The s _ i _, h _ i _ and C N S (central nervous system) (Bio Disk # 2860P) form from ____side (E _ _ _ D _ _ M) embryonic tissue layers. Ref. #25

Which of these three tissues or organs (prior sentence) does not seem logical, since
this region is now totally hidden within your body? _________________

b. The middle embryo layers (M _ S O _ _ R _ ) (Ref. #26) become the
c _ r _ u _ a _ o _ y, l _ c _ m _ t _ o _, e _ c _ e _ o _ y, and
r _ p _ o _ u _ t _ v _ systems (g _ n _ d _)

c. The d _ g _ s _ i _ e & r _ s _ i _ a _ o _ y systems form from ____side
(E _ D _ _ E _ M) (Ref. #27) embryo tissue layers

Click here for the answers to this section.

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