variation and sexual reproduction

Question 1

Costs of sexual reproduction

Answer 1

-Males unable to produce offspring
-only half of each parents genome passed onto offspring disrupting successful parental genomes

Question 2

Benefits of sexual reproduction

Answer 2

Benefits outweigh disadvantages due to increase in genetic variation in population

Question 3

Genetic variation provides

Answer 3

The raw material required for adaptation, better chance of surviving changing selection pressures

Question 4

What explains the persistence of sexual reproduction

Answer 4

Red Queen hypothesis

Question 5

How do hosts have greater fitness

Answer 5

Can resist and tolerate parasitism

Question 6

How do parasites have greater fitness

Answer 6

Better able to feed reproduce and find new hosts

Question 7

Sexually reproducing hosts costa

Answer 7

Genetic variability in offspring reduces chance that all will be susceptible to infection by parasites

Question 8

Asexual advantages

Answer 8

Whole genomes are passed on from parent to offspring, this is useful in narrow stable niches or when recolonising disturbed habitats

Question 9

Asexual reproduction

Answer 9

Just one parent can produce daughter carlos and establish a colony of unlimited size over time

Question 10

Examples of A reproduction in eukaryotes

Answer 10

• Vegetive cloning in plants
• Parthenogenesis

Question 11

Parthenogenesis

Answer 11

Reproduction from a female gamete without fertilisation.

Question 12

Parthenogenesis is more common in

Answer 12

• Cooler climates which are disadvantageous to parasites
• Regions of low parasite density or diversity ( because reduced selection pressure

Question 13

Disadvantages of asexually reproducing pops

Answer 13

Not able to adapt easily to changes in their environment but mutations can occur that provide some degree of variation. This enables some natural selection and evolution to occur

Question 14

how do asexually reproducing organisms increase variation

Answer 14

Have mechanisms for horizontal gene transfer between individuals to increase variation, eg plasmids of bacteria and yeasts

Question 15

Prokaryotes

Answer 15

Can exchange genetic material horizontally. This results in faster evolutionary change in organisms that only use vertical transfer

Question 16

Meiosis

Answer 16

Forms variable gametes. It is the division of the nucleus that results in the formation of haploid gametes from a diploid gametocyte

Question 17

How does increased variation occur

Answer 17

Through production of haploid gametes by meiosis

Question 18

Homologous chromosomes are pairs of chromosomes that

Answer 18

• have the same sequence of genes at the same loci
• are the same size
• have the same position of centromere