Natural Selection

Question 1

What are selection pressures?

Answer 1

• environmental factors affect survival and reproduction
• better adapted have higher chance of surviving and passing on advantageous allelle traits to future gen increasing frquency in gene pool

Question 2

What does fitness mean?

Answer 2

-organism’s ability to survive and reproduce.
- higher fitness are more likely to transfer their genes to the next generation

Question 3

Give examples of selection pressures:

Answer 3

• Predation
• Competition for resources
• Climate change
• Disease

Question 4

What is an allelle?

Answer 4

• variant form of a gene
• diff allelles = diff observable traits

Question 5

What is genetic diversity?

Answer 5

• total number of diff allelles in pop
• genetic varation as diff combinations = combo = diff proteins = characteristics

Question 6

What is the process of NS? (5)

Answer 6

1) There is variation in characteristics within a species.
2) More genetic variation emerges within a population due to random mutations.
3) Individuals with alleles that code for traits that are advantageous for survival are more likely to reproduce.
4) These advantageous alleles are passed down to offspring.
5) Over time, these beneficial alleles become more common in the population.

Question 7

Outline antibiotic resistance in bacteria…

Answer 7

1) Some bacteria develop random mutations that provide resistance to antibiotics.
2) When antibiotics are used, only the resistant bacteria survive, while the others die off.
3) The resistant bacteria reproduce, passing on resistant alleles to their offspring.
4) Over time, the proportion of resistant alleles increases, leading to mostly resistant bacteria.

Question 8

What is the impact of antibiotic resistance?

Answer 8

• complicates treatment options
• increases healthcare costs
• raises mortality rates in humans

Question 9

outline pesticide-resistance in insects..

Answer 9

1) Some insects randomly develop a mutation providing resistance to a pesticide, so they survive while the majority die.
2) The resistant individuals reproduce, passing on their resistance alleles to their offspring.
3) The frequency of resistance alleles increases over generations, increasing the population’s overall resistance to the pesticide.
4) Eventually, the pest population evolves to a point where the pesticide is no longer effective.

Question 10

What is the impact of pesticide-resistant insects?

Answer 10

-increased pesticide use
- environmental damage
- crop losses