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Do Now: In your Science
Notebooks
Read section 4.3 p. 117-122 C
Copy and answer the following questions:
1. What kind of cell is produced by meiosis?
2. What is fertilization?
3. Describe one difference between meiosis
and mitosis.
Objective:
• I will be able to explain the difference
between asexual and sexual reproduction.
Define cell division.
• Quiz on Genetics next class!!! Be prepared.
"Things turn out the best for
people who make the best of
the way things turn out."
-- John Wooden
A HISTORY OF DNA
SEE p. 292-293
• Discovery of the DNA double helix
A. Frederick Griffith – Discovers that a factor
in diseased bacteria can transform harmless
bacteria into deadly bacteria
(1928)
B. Rosalind Franklin - X-ray photo of DNA.
(1952)
C. Watson and Crick - described the
DNA molecule from Franklin’s X-ray.
(1953)
Types of Reproduction
Asexual & Sexual
Purpose of Reproduction
• To make sure a species can continue.
*Reproduction is the process by which an
organism produces others of its same
kind.
Reproduction:
The Continuity of Life
Reproduction
Asexual
Reproduction
Sexual
Reproduction
*Asexual Reproduction
• Asexual reproduction results in offspring
that are genetically identical to the parent
organism
• This means they will be genetically alike.
Types of Asexual Reproduction
1. Budding
2. Regeneration
3. Binary Fission
1. Budding
• Process by which a new, duplicate plant or
animal begins to form at the side of the
parent and enlarges until an individual is
created.
• Very common in plants.
Hydra ("water serpent") is the name of the Lernaean Hydra, a
many-headed serpent in Greek mythology.
Hydra is a species of simple fresh-water animals. They can be found in most unpolluted fresh-water ponds, lakes, and streams in the
temperate and tropical regions and can be found by gently sweeping a collecting net through weedy areas. They are multicellular
organisms which are usually a few millimeters long and are best studied with a microscope.
http://judyepstein.com/images/DesertImages/Budding-Purple-LG.jpg
2. Regeneration
• The ability to repair lost or damaged
tissues, organs or limbs.
• Common feature in worms and starfish.
• Human regeneration. Salamander growing
3. Binary Fission
• Becoming two by division of the complete
organism.
“Which protists is in this photo?”
Bunny Hop to Ms. Jones with the correct
answer for a treat.
A bacterial cell reproducing by binary fission. The two resultant daughter cells are genetically identical.
(Photo: Dr. Vincent A. Fischetti, Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller
University)
*Sexual Reproduction
• Requires two sex cells – egg and sperm
• The egg and sperm cells join (fertilization)
to form an entirely new organism
• Sexual reproduction results in offspring
that are genetically different from the
parent organisms
Candy ChallengeDance to Ms. Jones when you finish.
• On a separate sheet of paper, complete
the following chart.
• Using
http://learn.genetics.utah.edu/content/varia
tion/reproduction/ read the directions
Name of Organism
Name of Organism
Type of Reproduction
Type of reproduction
Mitosis & Meiosis
…the processes of cell division…
*Mitosis

The purpose of mitosis is to produce the
cells of the body



is a type of asexual reproduction
where a cell divides into two daughter
cells, each of which has the same
number of chromosomes as the original
cell (46 chromosomes in humans).
The purpose in humans is for growth and
repair of cells.

Examples: internal organs, skin, bones, blood, etc.
*Meiosis
 the purpose of meiosis is to produce sex
cells (sperm & egg)
is a type of sexual reproduction
During meiosis the number of chromosomes
in each sex cell is half the normal number of
chromosomes found in the parent.
(23 chromosomes in Humans)
 The offspring gets the normal number of
chromosomes-half from each parent.
This may help you remember these terms:

MITosis takes the cell and Makes It Two (diploid)

Meiosis has to do with sex cells

From the cell’s point of view:
 mITosis results in Identical Twins
 mEioSis results in Egg and Sperm (haploid)
Clyde Freeman Herreid – Dept. of Biological Sciences: Buffalo State Univ. of New York
*Variation


The amount of change or difference within
a species. All living things show
characteristics of their species.
All living things are different in some way.
Think about this…
How can you explain why offspring that
result from sexual reproduction have
greater variation than offspring that
result from asexual reproduction?
Fill in the blanks
On a separate sheet of paper.
Compare and Contrast


Use the terms and facts given to create a
Venn diagram comparing and contrasting the
process of mitosis and meiosis
Jog to Ms. Jones with your completed venn
diagram for a PRIZE.
Meiosis:

As in mitosis, if a cell wants to make a duplicate of itself,
it first must copy its DNA (part of a chromosome).

Results in reproductive cells (sperm, eggs, etc).

Part of each parent is carried to the four new cells.

Meiosis has evolved to solve a problem.

The problem is this: some organisms have sex with other
organisms – that is, they combine their genes together
(creating genetic diversity).

Why would this be a problem?