Chapter 5.4 asexual reproduction

5.4 Asexual Reproduction

KEY CONCEPTMany organisms reproduce by cell division.


Objectives:• Compare and contrast binary fission and mitosis.• Describe how some eukaryotes reproduce through

mitosis.

5.4 Asexual Reproductiona. Sexual reproduction - joining of two specialized cells (gametes - egg and sperm), one from each parent 1). Offspring are genetically

unique 2). Mixture of genes from both parents

5.4 Asexual Reproductionb. Asexual reproduction - creation of offspring from a single parent. Offspring genetically identical


Difference between asexual and sexual reproduction:

Asexual

• Asexual reproduction produces genetically identical offspring.

Sexual

• Sexual reproduction produces genetically unique offspring.


Binary fission is similar in function to mitosis.

• Asexual reproduction is the creation of offspring from a single parent.– Binary fission produces two daughter cells genetically

identical to the parent cell.– Binary fission occurs in

prokaryotes.


steps of binary fission

• 1. The bacterial chromosome is copied. Both copies attach to the cell membrane.

• 2. As the cell elongates, the chromosomes separate.

• 3. The membrane is pinched inward and a new wall is laid down between two chromosomes.

parent cell

DNA duplicates

cell begins to divide

daughter cells


Advantages and Disadvantages of Asexual reproduction

Advantages: •No need to find a mate.

•Can get good varieties of plants and animals.

•Desired characteristics can be achieved.

Disadvantages: •Identical offspring all respond in same way to environment.•Same disease can be transferred to next generation.•No variation within species.•Less efficient.

5.4 Asexual ReproductionB.

1.In environments that don’t change, asexual may be better. If they are well suited to environment may be more efficient.

2. In changing environments sexual reproduction produces genetic diversity which raises chances for survival.


• Fragmentation is the splitting of the parent into pieces that each grow into a new organism.

• Vegetative reproduction forms a new plant from the modification of a stem or underground structure on the parent plant.


Reproduction in sea anemone:• sexually and asexually by dividing in half or breaking off

small pieces from its base

Education

Chapter 5.4 asexual reproduction