Concept 1

Question 1

evolution

Answer 1

change in populations over time,
makes descendants genetically different

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

where organisms with the “best” traits
are favored and live longer and reproduce

Question 5

Fitness

Answer 5

how well an organism can survive in its environment

Question 6

Adaptation

Answer 6

an organism that can 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

random change in the allele frequency happens in the population

Question 9

Gene flow

Answer 9

movement of genes
into or out of a population

Question 10

Sexual selection

Answer 10

favors traits that potentially
decrease survival, but increase reproduction

Question 11

Genetic equilibrium

Answer 11

no changes in the allele frequencies over time; evolution is not occurring

Question 12

Explain the principles of natural selection

Answer 12

• 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
• over production and competition
• variation
• some variations live longer
• the ones that live longer reproduce

Question 13

Write a real world example of evolution and how each principle was met

Answer 13

In a population of frogs, there is natural variation that exists in
their coloration. One particular season precipitation greatly decreases, and the foliage turns brown. The frogs that lack brown coloration can’t blend in and hide from their predators so they die before they can reproduce and pass on their traits. Brown coloration is favored and thus
an adaptation that should become more common over time if continually favored by the environment

Question 14

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

Answer 14

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 15

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

Answer 15

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

Question 16

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

Answer 16

• 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 17

Sketch pictures and explain the difference between the
three modes of selection

Answer 17

Directional favors one extreme, disruptive favors both
extremes, stabilizing favors the average

Question 18

Describe at least three mechanisms of microevolution

Answer 18

• Genetic drift = random change in a population that often decreases variation
• Gene flow = the movement of genes into or out of a population, affecting the variation within the population
• Sexual selection (non-random mating) = favoring traits that increase reproduction over survival

Question 19

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

Answer 19

• 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 20

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

Answer 20

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