Reproduction

Question 1

Compare sexual reproduction with asexual reproduction

Answer 1

1. Sexual has 2 parents. Asexual has 1.
2. In sexual, gametes (sex cell) are formed. In asexual no gametes are formed.
3. In sexual, new organisms have a combination of genes from both parents, therefore are genetically unique. In asexual new organisms are exactly the same and are clones of the parent

Question 2

List advances of sexual reproduction

Answer 2

1. Offspring are all slightly different from each other and their parents. I.e genetic pooling occurs. ( larger variety)
2. This variation allows for those offspring with the strongest genes to survive and reproduce and continue the species.

Question 3

List disadvantages of sexual reproduction

Answer 3

1. A suitable mate is needed

2. Generally a slower rate of reproduction,

Question 4

List advantages of asexual reproduction

Answer 4

1. Occurs quickly
2. Only one individual needed, I.e no need to search for suitable mate,
3. Many offspring can be produced in short space of time

Question 5

List disadvantages of asexual reproduction

Answer 5

1. All offspring are identical. I.e. No variation occurs.

2. Only occurs when conditions are favourable I.e. Good food, enough water, correct temperature,

Question 6

Define binary fission

Answer 6

Is asexual reproduction by a single cell splitting in two.

Question 7

Explain how binary fission takes place

Answer 7

Cells nucleus contains chromosomes which replicate. They then move to opposite ends of the cell. The cell then divides resulting in two new cells with exactly the same amount of chromosomes.
This can occur every 20 mins under good conditions,

Question 8

Define spore formation

Answer 8

A spore is a single cell surrounded by a protective coat. Spores are produced and spread, when they land pm a suitable place they begin to grow (germinate) to form a new plant. They grow on the under sides of ferns etc.

Question 9

Define vegetative asexual reproduction

Answer 9

When a part of an existing plant ‘breaks off’ and gives rise to a new plant

Question 10

Give examples of vegetative asexual reproduction

Answer 10

1.cuttings- when a stem is cut off and placed into water, sprouts roots and can then be planted.
Eg impatiens.
2. Tubers- eg potatoes.
3. Bulbs- onion, daffodils etc.

Question 11

Why is reproduction essential

Answer 11

It is essential for the survival and continuation of a species.