Transcript Asexual vs Sexual Reproduction

Types of Reproduction
Types of Reproduction
Asexual
Asexual reproduction occurs when a new organism is produced from
one parent. The genetic material of the new organism is identical to
the genetic material of the parent. So the offspring and the parent
have all of the same traits.
Organisms that are smaller and
less complex are more likely to
reproduce asexually. Single-celled
organisms like bacteria and
protists reproduce asexually.
Many plants and fungi can
reproduce asexually as well. A few
animals can reproduce asexually.
This animation shows a cell reproducing asexually.
Asexual Types of Reproduction
Budding
Three types of asexual reproduction are budding,
regeneration, and fission.
Budding is the process when a new organism begins
to form on the side of the parent and eventually breaks
off. Budding is most common in plants and fungi.
Hydra are part of the animal
kingdom. Hydra reproduce
by budding.
You can see the new little
hydra growing off the side of
the larger, parent hydra.
Picture from
http://devcell.bio.uci.edu/images/Hydra.jpg.
This picture shows
a magnification of
budding yeast.
Asexual Types of Reproduction
Regeneration
Regeneration is the ability to restore lost or damaged tissues, organs,
or limbs. It is most common in animals that do not have a backbone
like worms and starfish. Sometimes, if an organism loses a limb or if
the organism is split into two parts, both parts will regenerate the
missing pieces, creating two organisms from one.
Planaria regeneration. In the final picture, two planaria worms are formed.
Picture retrieved from http://www.ub.edu/planaria/ January 20, 2010.
Asexual Types of Reproduction
Binary Fission
Binary fission occurs when a single celled
organism splits into two cells. Bacteria and
protists reproduce by binary fission.
First the parent cell makes a copy of its
genetic material (the green, squiggly circle),
then the cell membrane pinches in and two
new daughter cells split apart.
Because the cell copied its genetic material,
the two cells have the same traits.
Types of Reproduction
Sexual
Sexual Reproduction requires two parents.
The female parent provides an egg cell, and
the male parent provides a sperm cell. The
egg cell and the sperm cell combine to form a
new individual.
The egg cell has genetic material from the
female parent and the sperm cell has genetic
material from the male parent. Therefore, the
offspring will have genetic material from both
parents. This is called genetic variation.
Sexual reproduction allows new individuals to
have genetic variation because they get a mix
of traits from two parents.
Egg cell
Sperm cell
New individual
Sexual Types of Reproduction
Plants - Pollination
Pollination is a form of sexual reproduction. Pollination occurs in
plants. Pollen is taken from the male parts of one plant and delivered
to the female parts of another plant, usually by an insect. The pollen
then travels inside the flower and fertilizes an egg. The egg will grow
into a seed which can become a new plant.
Pollination also allows for
genetic variation because
the traits from two plants
are mixed.
Sexual Reproduction in Animals
In animals, sexual reproduction encompasses the fusion of two
distinct gametes to form a zygote. Gametes are produced by a type
of cell division called meiosis.
The gametes are sex cells that contain only one set of chromosomes,
while the zygote has two sets of chromosomes.
In most cases, the male gamete, called sperm, is mobile and has a
flagellum. The female gamete, the egg, isNot mobile and is large
compared to the male gamete.
Sexual Reproduction in Animals
There are two mechanisms by which fertilization can take
Place.
The first is external (eggs fertilized outside of the body)
The second is internal (eggs fertilized within the female
reproductive tract.
Types of Reproduction
Sexual vs. Asexual
Take a look at the table below. It summarizes the important differences
between sexual and asexual reproduction.
Sexual
Reproduction
Asexual
Reproduction
Number of
Parents
2 parents
1 parent
Genetic
Variation
Lots of genetic
variation (a mix
of traits from 2
parents)
No genetic
variation (the
same traits from
only 1 parent)
Sexual Versus Asexual Reproduction
What are the advantages of sexual reproduction?
What are the advantages of asexual reproduction?