U6 C1

Question 1

Evolution

Answer 1

The process of biological change in populations over time that
makes descendants genetically different from their ancestors

Question 2

Microevolution

Answer 2

• Small scale evolution affecting a single population`\

Question 3

Macroevolution

Answer 3

• Large scale evolution affecting a species across populations

Question 4

• Natural selection

Answer 4

Mechanism of evolution where organisms with the “best” traits
are favored and thus live longer and reproduce more, causing
changes in the population over time so that the fittest survive

Question 5

Fitness

Answer 5

A measure of how well an organism can survive in its
environment

Question 6

• Adaptation

Answer 6

A feature that allows an organism to better survive in its
environment

Question 7

*Gene pool =

Answer 7

• The combined alleles of all individuals in a population

Question 8

*Genetic drift

Answer 8

• Mechanism of evolution that occurs when random change
  in the allele frequency happens in the population`

Question 9

*Gene flow =

Answer 9

• Mechanism of evolution caused by the movement of genes
  into or out of a population

Question 10

*Sexual selection

Answer 10

• Mechanism of evolution that favors traits that potentially
  decrease survival, but increase likelihood of reproduction

Question 11

*Genetic equilibrium

Answer 11

When there are no changes in the allele frequencies in a
population over time, and thus evolution is not occurring

Question 12

Explain the principles of natural selection. Write a real
world example of evolution and how each principle was
met.

Answer 12

*Overproduction of offspring, Variation, Adaptation, Descent with modification,
There is an overproduction of offspring that leads to more
organisms than resources, and thus creates competition.
* Within any population there will be variation.
* Some innate variations will allow organisms to better survive
than others (adaptations).
* Over time, those traits should become more common because
organisms with those traits will live longer and reproduce more,
creating descendants with modifications from their
ancestors.

Question 13

Explain how diversity within a species has resulted
in an increase in fitness (survival of the fittest).

Answer 13

The more diverse a species is the less likely the entire
species can be eliminated by a sudden event.
- This is why sexual reproducers tend to be better at surviving in
regularly changing environments than asexual reproducers,
whose only source of variation is random mutation.

Question 14

List the different factors that contribute to genetic
variation and explain which is considered to be the
“ultimate” source.

Answer 14

• Random mutations
• Ultimate source because the others don’t affect asexual
  reproducers
• Genetic recombination during meiosis
• Migration/gene flow

Question 15

Explain what is meant by the phrase, “Individuals don’t
evolve, populations do.”

Answer 15

• Natural selection acts on traits that are heritable, not traits that
  are acquired in a lifetime.
• It is impossible for an individual to change their allele
  frequencies.
• Thus only populations can evolve because only within
  populations do allele frequencies change over time.

Question 16

3 mechanisms of microevolution

Answer 16

Genetic drift
Gene flow
Sexual selection (non-random mating)

Question 17

Genetic drift

Answer 17

random change in a population that often
decreases variation

Question 18

Gene flow

Answer 18

the movement of genes into or out of a
population, affecting the variation within the population

Question 19

Sexual selection (non-random mating)

Answer 19

= favoring traits that
increase reproduction over survival

Question 20

Give an example of how genetic drift would have a
bigger impact on a smaller population than a larger
one.

Answer 20

• If a hurricane comes and flooding occurs and wipes out half of
  a population of 1,000 insects, there are still 500 remaining and
  most likely a decent amount of innate variation within them.
• But if that same flooding occurs in a population of 100 insects
  and only 50 survive, most likely a lot of variation was eliminated
  and if those 50 only reproduce with each other, the traits that
  exist in their alleles will be favored and the others will die out of
  the population.

Question 21

List the 5 conditions that must be met for evolution
to not occur.

Answer 21

• No mutations
• No natural selection
• LARGE population
• No migration
• Random mating