4.6 Inheritance, Variation And Evolution Flashcards Preview

Biology > 4.6 Inheritance, Variation And Evolution > Flashcards

Flashcards in 4.6 Inheritance, Variation And Evolution Deck (13)
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1
Q

What does asexual reproduction involve?

A

One parent
No gametes
Mitosis only
Genetically identical offspring

2
Q

What does sexual reproduction involve?

A

Two parents
Gametes involved
Meiosis
Genetically variable offspring

3
Q

What are the gametes involved in animals?

A

Sperm and egg

4
Q

What are the gametes involved in plants?

A

Pollen and egg

5
Q

How many chromosomes are there in asexual compared to sexual?

A

In asexual reproduction, all cells throughout the life cycle have the same number of chromosomes, but in sexual reproduction there are stages where the chromosomes are halved

6
Q

What are the advantages of asexual reproduction?

A

Only one parent needed so if you live in a hostile environment you can still reproduce. No energy wasted finding mate

No energy finding a mate and competing with rivals

Faster

Identical offspring produced- great if conditions are favourable and organism well suited to exploit resources

7
Q

Advantages of sexual reproduction

A

Variable offspring- if environment changeable then new variants might have a survival advantage that could lead to the survival of the species by natural selection

Selective breeding leads to increase in food production

8
Q

Examples of asexual reproduction

A
Binary fission in bacteria
Budding in yeast
Spider plant producing runner
Daffodils
Strawberry plant
Fungi by spores
Malarial protists
9
Q

How do strawberry plants reproduce asexually?

A

They send out long shoots called runners, which touch the ground and grow a new plant

10
Q

How do daffodils reproduce asexually?

A

Daffodils produce lots of smaller bulbs, which can grow into new plants

11
Q

Describe meiosis

A

GETTING READY First the DNA is replicated and the cell grows. There is an increased number of mitochondria and ribosomes

MITOSIS 1 Then separation of homologous chromosomes, I chromosome from each pair to each cell after crossing up

MITOSIS 2 same as mitosis

CYTOKINESIS cytoplasm and cell membrane divide. 4 gametes that are genetically variable are produced

12
Q

Why is meiosis important?

A

Because it halves the number of chromosomes in gametes. This means fertilisation can restore the full number of chromosomes

23 + 23= 46 chromosomes

Sperm + egg = fertilised egg cell

13
Q

What organisms can reproduce both sexually and asexually?

A

Many plants e.g. Using bulbs and runners

Many fungi can make spores

Malaria parasites reproduce sexually in the mosquito and asexually in humans