Transcript Asexual Reproduction

Characteristics of Life:
All Organisms Can Reproduce
All Organisms Grow and Develop
Asexual Reproduction
Sex!
1. Asexual Reproduction
a) involves only 1 parent
b) offspring genetically
identical to parent
c) involves regular body
cells (somatic)
d) its quick with no mate
e) Offspring’s genes all
come from the same
parent without the
fusion of egg and
sperm
1. Sexual Reproduction
a) involves 2 parents
b) offspring genetic mix
of both parents
c) involves specialized sex
cells
d) its slow
e) fusion of two haploid
gametes (sperm and
egg) to form a diploid
zygote
Asexual Reproduction - Characteristics
1. Requires only one parent
2. Offspring have 100% the same chromosomes
as the parent.
a) Most unicellular organisms reproduce this way.
3. Involves the process of mitosis
a) Involves only mitotic cell division = each offspring
has exactly the same heredity as its parent.
b) Usually rapid compared to sexual reproduction.
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Types of Asexual Reproduction
1.
2.
3.
4.
5.
6.
Binary Fission
Budding
Regeneration
Fragmentation
Plant Cuttings
Cloning
Asexual Reproduction – Binary Fission
1. Simplest form of asexual reproduction.
2. Happens in bacteria, amoeba, some algae
3. One parent cell splits into 2 (equal halves)
identical daughter cells
4. Each daughter cell becomes a new
individual
Binary Fission
Rod-Shaped Bacterium,
hemorrhagic E. coli
2 daughter cells are identical to parent
Asexual Reproduction - Budding
1. Happens in yeast, hydra, corals
2. Parent organism divides into two
unequal parts.
3. Parent produces a bud
4. Daughter cell forms from outgrowth or
bud off parent
5. Bud gets detached and develops into
offspring which is identical to parent
Budding
Asexual Reproduction - Regeneration
1. The ability to re-grow lost or
damaged body parts.
2. Hydra, planaria, starfish, and
earthworm. More complex animals
less able to re-grow parts.
3. Crab can re-grow a claw. Some
reptiles can re-grow a tail. Most
mammals can repair damaged tissue
but can not re-grow missing parts.
Regeneration
Humans?
Asexual Reproduction - Fragmentation
1. Fragmentation is a means of asexual
reproduction whereby a single parent
breaks into parts that regenerate into
whole new individuals.
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Asexual Reproduction – Plant Cuttings
1. Vegetative reproduction is a
type of asexual reproduction in
plants that relies on multicellular structures formed by the
parent plant.
2. It has long been exploited in
horticulture and agriculture,
with various methods employed
to multiply stocks of plants.
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Which is Better?
It depends!
Asexual Reproduction
1. Advantages
a) does not require special
cells or a lot of energy
b) can produce offspring
quickly
c) in a stable environment
creates large, thriving
population
2. Disadvantages
a) limited ability to adapt
(no genetic diversity)
b) face massive die-off if
environment changes
Sexual Reproduction
1. Advantages
a) lots of genetic
variation within a
species
b) able to live in a variety
of environmental
settings
c) able to adapt to changes
in the environment
2. Disadvantages
a) needs time & energy
b) produce small
populations
Meiosis - Sexual
Mitosis - Asexual
Forms sex cells (sperm
and eggs)
Responsible for growth,
differentiation, and
asexual reproduction
½ the number of
chromosomes compared to
the parent cell
Genetically
identical to parent
cell
One replication and
two divisions
One replication and one
division
4 daughter cells
formed
2 daughter cells
formed