Chapter 14

Question 1

Why do mutations proliferate more quickly in prokaryotes than eurkaryotes?

Answer 1

• Bacteria have much shorter lifespan and much quicker generations, so the effects of natural selection can happen faster, and allele frequencies in populations change much quicker
• Bacteria are haploid, having only one allele for each gene. New alleles have effects immediately.

Question 2

In plants and animals, what factors serve as buffers against mutation?

Answer 2

1. longer lifespan
2. Diploid genomes
3. Low mutation rate (1 mutation in 100,000 genes PER GENERATION!)

Question 3

What is a mutation?

Answer 3

A R A N D O M change in DNA nucleotide sequence

Question 4

Most mutations are ______

Answer 4

Harmful. But on some occasions they can actually improve reproductive success. Take for example the DDT-resistance flies.

Question 5

What is a population?

Answer 5

A group of individuals of the same species that live in the same area and interbreed

Question 6

What is a gene pool

Answer 6

Total collection of genes in a population at a given time

Question 7

Evolution uses genetic variation!! What are the two different sources of genetic variation?

Answer 7

1. Mutation

2. Sexual reproduction

Question 8

What generates new allele assortments? (3 different processes)

Answer 8

1. Crossing over during prophase 1 of meiosis
2. Random arrangement of alleles during metaphase 1 of meiosis
3. Random fertilization

Question 9

2 scales of evolutiion:

Answer 9

Microevolution and macroevolution!

Question 10

Microevolution is…

Answer 10

• Changes in allele frequencies within the gene pools of populations from one generation to the next
  
  • Genetic variation as the raw material

Question 11

Macroevolution is…

Answer 11

• Major changes recorded in the history of life
○ Eg. Evolution of flight
• Occurs above the species level, over long periods of time
• Encompasses origins of new taxonomic groups

Question 12

What are the mechanisms of microevolution?

Answer 12

Natural selection
Genetic drift
Gene flow

Question 13

What are the 3 main contributing factors of macroevolution?

Answer 13

1. Continental drift
2. Mass extinctions
3. Adaptive radiations

Question 14

Explain the 3 mechanisms of microevolution.
Natural Selection
Genetic drift
Gene flow

Answer 14

Natural selection: when certain alleles are favoured by environmental factors, and the organisms carrying those alleles have higher chances of surviving, changing the overall allele ratios in the gene pool.

Genetic drift: Alterations of allele frequency that happen due to random chance. Greater impact in smaller populations.

Gene flow: Alterations of allele frequency, occurs when alleles transfer from one population to another

Question 15

Does genetic drift produce adaptations?

Answer 15

No, allele frequency changes happened due to random chance

Question 16

What are the two different types of genetic drift?

Answer 16

1. Bottleneck effect

2. Founder effect

Question 17

The bottleneck effect is a mechanism of _______(micro/macroevolution), namely ______(which mechanism??). It occurs when…

Answer 17

microevolution, genetic drift

Occurs when a population is drastically reduced. Allele frequencies generally change during such an event.

Question 18

The founder effect is a type of _______. It occurs when…

Answer 18

Genetic drift!

Occurs

Question 19

How does gene flow happen?

Answer 19

When fertile organisms move from one population to another

Or whenever gametes transfer, eg. Pollen transfer

Question 20

Gene flow affects more than one population. How does between-population variance, and within-population variance?

Answer 20

Decreases between-population variance.

Can increase within-population variance (of new population).

Question 21

What causes mass extinction?

Answer 21

Natural disaster due to habitat loss, climate change.
Evolution of new predators
Evolution of new competitors.

Question 22

5 big daddy mass extinctions killed _% of earth species.

Answer 22

50%+!!!!!!!

Question 23

Why is the 6th “mass extinction” maybe currently happening???

Answer 23

• more than 1000 species extinct in the last 400 years!
• this is “between 100-1000” times the normal rate of extinction.

:’( W T F

Question 24

Continental drift caused by

Answer 24

ViOLenT tEcTONiC activity!!!!!!!

Whacky plates! Earthquakes!

Question 25

How long does it take for biodiversity to recover post-quake?

Answer 25

5,000,000-10,000,000 years!!

Question 26

tf is adaptive radiation?

What causes it?

Answer 26

• rapid diversification; emergence of new unique organisms from ancestral species.
• occurs as a result of environmental change opening up new environmental niches. eg. Result of predator death, like when dinosaurs died and prey could flourish.