Transcript Reproduction Websitex

Reproduction
Notes
I. Reproduction
A. Asexual reproduction – offspring arise
from a
single parent and inherit all
of the genes of that parent only
1. Offspring have 100%
of the
same chromosomes as the parent
2. Offspring are exact “clones” of
the parent
Asexual Reproduction
• 3. Most uni cellular organisms
reproduce this way
•
4. Mitosis – simple duplication
of all of its parts, two daughter
cells formed
5. Types:
a. Binary fission – every
organelle is copied
and the organism divides into two
equal halves
- Bacteria and protist
b. Budding – new individual
develops from an outgrowth of a
parent, splits into two unequal
halves and lives independently
- Hydra and sponge
c.
organism
– body part
has broken off and the
grows a new one
Regeneration
- Starfish and flatworm
d. Fragmentation – single parent
breaks into parts that regenerate
into whole new individuals
- Planarians
e. Sporulation – production of
many spores in a spore case
(spore – nucleus and
cytoplasm within a hard case)
- Molds, mushrooms and ferns
f.
Vegetative reproduction
– a new
plant grows from a vegetative part
- Bulb – short underground stem
with stored food in leaves
(onion and tulip)
- Corm – short underground stem with
stored food in stem (water chestnut and
crocus)
- Tuber – enlarged underground stem
(potato and yam)
- Runner – horizontal stem with buds along
ground’s surface (strawberry and spider
plant)
- Rhizome – underground horizontal stem
(ginger and iris)
- Cutting – cut a piece of plant
(Philodendron)
- Grafting – stem or bud of one plant is
joined permanently to another (rose and
apple tree)
- Layering – stem is bent over and covered
with soil (raspberry)
B.
Sexual reproduction
– offspring arise from 2 parents
that share half of the genetic
information
1. Offspring have 50% of the
chromosomes from each parent
2. Offspring share the
characteristics of each parent
Sexual Reproduction
3. Meiosis – cell division that reduces
the chromosome number by
half, 4 daughter cells formed
4. Types:
a. Internal – egg is fertilized by
the sperm inside the female
- Mammals, birds, reptiles, insects and
spiders
b.
External – egg is fertilized by the
sperm outside of the female
- Female lays eggs and male fertilizes
them
- Fish, some amphibians and flowering plants
Reproduction Pros
Asexual
Sexual
Do not need
to find a mate
Genetic diversity
(less chance of
getting harmful
traits from parents)
Cons
No genetic diversity
(any harmful traits
that the parent has
will be passed on to
offspring)
Need to find
a mate
Sexual vs. Asexual: Can you tell
which one it is?