Two Ways to Reproduce
WALT:
• the two types of reproduction
• the advantages of each type of reproduction
Sexual Reproduction
• Get genes from both mum and dad
• Inherits mixture of features from both parents
• Females produce sex cells (gametes) called
eggs and male gametes are called sperm
• A sperm and egg fuse together to make the
offspring = fertilisation
Asexual reproduction
• Offspring produced in this way get all
their genes from just one parent
• So have exactly the same genes as
parent
• All are clones of the parent
• Doesn’t need sex
cells
• Individual just splits
in two
e.g amoeba, bacteria
• Or a part divides off
e.g. hydra, starfish
Bacteria reproducing asexually
Sexual vs Asexual Reproduction
Advantages of Asexual reproduction
• Only one parent needed
• All offspring are clones
Advantages of Sexual reproduction
• All offspring are different
Questions
1. What are the disadvantages of asexual
reproduction?
2. Explain why variation is sometimes an
advantage and sometimes a disadvantage
3. Start off with one bacterium and assume
it reproduces once every 20 minutes. How
many bacteria would you have after 3
hours?
What is a clone?
A clone is genetically identical to
its “parent”
Cloning
• Dolly the sheep
was the first
mammal to be
cloned from
the DNA of an
adult.
• Here she is with
her first-born
lamb, Bonnie.
• Roslin Institute,
Edinburgh, 1996
Animal Cloning
• The goal of cloning is to take control of
the reproductive process.
• You are able to select the specific
combination of genes to get what you
want.
• That's appealing to people who breed
animals.
Cloning Dolly the Sheep
Where next??
Questions
1. Was cloning Dolly the sheep, a mammal
like us, a good idea?
2. Are there any circumstances in which
producing a human clone could be
acceptable?