Transcript Asexual vs. Sexual Reproduction

Asexual vs. Sexual
Reproduction
Modified from:
www.wayzata.k12.mn.us/ems/images/stories/academics/7th%2520Grade%2520Gol
d/Corens/asexual_vs._sexual_reproduction.ppt
Asexual reproduction
A form of reproduction which does not
involve meiosis or fertilization.
Asexual reproduction = one parent.
The primary form of reproduction for singlecelled organisms such as archaea, bacteria,
and protists.
Many plants and fungi reproduce mostly
asexually as well.
Sexual Reproduction
Results in increasing genetic diversity of the
offspring.
Characterized by two processes:
meiosis, halving of the number of chromosomes
fertilization, combination of two gametes and the
restoration of the original number of chromosomes
During meiosis, chromosomes usually cross over =
genetic recombination.
Primary method of reproduction for the vast
majority of visible organisms, including almost all
animals and plants.
Binary Fission
• Asexual
• Cell splits and
replicated DNA
goes with each
part
• Prokaryotes,
Bacteria
• + Fast and easy
• - Everybody has
the same DNA
Bacterial Conjugation
• Asexual, “Sexual”
• A bacteria shoots
out a tube and
sends a piece of its
DNA to another
bacteria
• Bacteria
• + Mixes DNA
• - “Parent” loses a
little piece of DNA
Fragmentation/ regeneration
• Asexual
• Body of parent
breaks and
produces
offspring
• Fungi, moss, sea
stars, planarian
• + Easy
• - Parent broken,
same DNA
Fragmentation/ regeneration
Moss
Budding
• Asexual
• Offspring grows out
of parent
• Yeast, hydras
• + Fast, somewhat
easy
• - Same DNA
Spore Formation
• Spore Formation – spores = small
specialized cells that contain a
nucleus and cytoplasm surrounded
by a thick outside wall which
protects the spore. Under the
right conditions the spore can rise
to a new organism. Found in
bacteria, molds, yeast, mushrooms,
mosses, ferns and some protozoans.
Spore formation
Vegetative Reproduction
• Bulb = Short
underground stem
surrounded by
thick leaves.
Contain stored
food. As the
plant grows it
produces new
bulbs which will
grow into new
plants. Tulips,
onions, and lilies.
• Tuber =
enlarged part of
an underground
stem that
contains stored
food. Potatoes
are tubers.
“Eyes” = tiny
buds that can
form a new
potato plant.
How you plant
potatoes. Great
potato famine.
• Runner or stolen =
horizontal stem
above the ground
with buds. If a
bud touches the
ground it will form
roots and stems
and start a new
plant.
Strawberries.
Sexual Reproduction
Pollination
• Sexual Reproduction
• Pollen is delivered to
female part of plant
• Flowering plants
• + Plants don’t have
to move, mixes DNA
• - Need external
source for pollination
to take place; wind,
bee, bat, butterfly
etc.
Pollination
Sexual Reproduction
• Sexual Reproduction
• DNA from 2
individuals merge to
form one
• Animals, Plants
• + Diverse DNA
• - Takes a long time,
2 individuals needed
Sexual Reproduction