1. Chapter 5 Cell Growth and Division Mr. Shilala DAHS
5.4 Asexual Reproduction
Chapter 5 Cell Growth and Division
Mr. Shilala
DAHS

2. KEY CONCEPT Many organisms reproduce by cell division.

3. Purpose of Reproduction
To make sure a species can continue.
Definition: Reproduction is the process by which an organism produces others of its same kind. 2 ways
Asexual or sexual
Asexual reproduction is the creation of offspring from a single parent. There are several types

4. Binary Fission and Mitosis
Binary fission is similar in function to mitosis
Binary Fission occurs in most Prokaryotes
Binary fission produces two daughter cells genetically identical to the parent cell.
parent cell
DNA
duplicates
cell begins
to divide
daughter
cells

5. Binary Fission and Mitosis
Prokaryotes have no nucleus but do have DNA
DNA in the shape of single circular chromosome
Chromosome copied and attached to cell wall
When cell is twice as large membrane pinches inward – cytokinesis
Cell wall forms

6. Advantages and Disadvantages of Asexual Reproduction
Environment determines what form of reproduction is most advantageous.
Advantages of Asexual reproduction
Favorable in environments that don’t change much.
Can be more efficient
Disadvantages
In environments that do change, identical offspring respond the same to changes in environment
Extinction can occur if genetic variation
is needed
Sexual reproduction
Increases genetic diversity
1 or more individual may survive change

7. Asexual reproduction itself is not more efficient, rather the associated costs of sexual reproduction are greater
Example
Two organisms each have 10 offspring
1 reproduces asexually
All 10 can have offspring of their own
The other 1 reproduces sexually
5 males and 5 females are produced
Only females can bear offspring
Must attract a mate
Involves energy, signals, and behaviors

8. Some eukaryotes reproduce through mitosis.
Budding
Forms a new organism from a small projection growing on the surface of the parent.
Very common in plants
bud
Hydra
Yeast

9. Fragmentation
Splitting of the parent into pieces that each grow into a new organism.
Sea Stars and Flatworms

10. Vegetative reproduction
Forms a new plant from the modification of a stem or underground structure on the parent plant
Sometimes referred to as cloning
Strawberries and potatoes

11. Regeneration
The ability to restore lost or damaged tissues, organs or limbs.
It is a common feature in invertebrates, like worms and starfish.