Problem Set 3.6: Asexual Reproduction Instructions: Read pages 364 to 367 in your text and answer the questions that follow.

1. List three characteristics of asexual reproduction.

only one parent is involved

offspring are identical to the parent

the cells that produce the offspring are not specialized for reproduction

2. List five different methods of asexual reproduction and briefly describe each one.

Method of Reproduction	Key Feature	Example
Binary Fission	Organism splits into 2 equal-sized offspring.	Occurs with single celled organisms e.g. bacteria
Budding	Offspring starts as a growth called a bud on the parent. Later bud detaches.	Occurs with one- or multi-celled organisms e.g. yeast
Spore Formation	Organism produces spores that contain a nucleus.	e.g. penicillin
Fragmentation (Regeneration)	Part of parent’s body breaks off and grows into a new organism.	e.g. starfish
Vegetative Reproduction	Parents send out a special stem at ground level from which a new offspring emerges. It grows roots and separates itself.	e.g. strawberries, spider plant

3. a) What is the difference between binary fission in bacteria and the same process in single-celled protists?

During binary fission in bacteria, the cell lengthens and its single molecule of DNA is duplicated.

Each of the two molecules becomes attached to a separate point on the cell membrane. The cell is

Then pinched in two between the two points in order to make two new cells.

b) Why is there a difference?

Protist cells have a complete nucleus and more complex chromosomes than bacteria. In these

organisms, mitosis occurs, followed by the division of the cell’s cytoplasm into two roughly equal

parts. Bacteria are simpler.

4. a) What is the difference between binary fission and budding?

There is an uneven division of the organism into two cells. In budding, a small growth appears

which develops into the new cell while binary fission divides the cell into two.

b) How are these two processes similar?

They both involve the reproduction of the simple chromosomes.

5. What does the word clone mean?

An offspring that is identical to the parent

6. a) In what way is spore formation different from other types of asexual reproduction?

Organisms that use this method produce cells specialized for reproduction. Each spore contains

a nucleus and a small amount of cytoplasm that can develop into a new organism.

b) In what ways is it the same?

Offspring are identical clones of parent.

7. Describe some methods of vegetative reproduction.

Plant sends out special stem from which offspring develop growing their own roots and become

independent plants. Strawberries send out runners along the ground surface while grasses send

out rhizomes under the ground to start the new offspring.

8. a) What are two advantages of asexual reproduction?

1. rapid reproduction

2. very successful in suitable environment

b) What is a potential disadvantage?

If the environment is changed in some way or a virus infects one organism, an entire population

may be wiped out because all offspring are identical and have identical characteristics.

9. Oysters are a major part of the diet of starfish. Because of this, people who catch oysters for a living used to try to kill starfish by cutting them up and throwing them back into the sea. Why might this practice not reduce the numbers of starfish?

It is possible that each piece of the cut up starfish thrown back into the water will grow into a new starfish which will also feed on the oysters compounding the problem.