Evolution

Question 1

Gene pool

Answer 1

All the genes of all the members of the population

Question 2

Genetic drift

Answer 2

A random change in allele frequencies that occurs in a small population

Question 3

Stabilizing selection

Answer 3

Type of natural selection in which phenotypes at both extremes are selected against

Question 4

Vestigial structure

Answer 4

Structure that evolution has reduced in size because it is no longer used

Question 5

Hardy-Weinberg theorem

Answer 5

Founding principle of population genetics proves allele and genotype frequencies d not change in a population that meets the conditions of no mutation, no migration, large population size, random mating, and no natural selection

Question 6

Homologous structure

Answer 6

Structure that is similar in related organisms because it was inherited from a common ancestor

Question 7

Disruptive selection

Answer 7

Middle of the phenotypic distribution are selected against, resulting in two overlapping phenotypes, one at each end of the distribution

Question 8

Directional selection

Answer 8

One of the two extremes phenotypes is selected for resulting in a shift the phenotypic distribution toward that extreme

Question 9

Analogous structure

Answer 9

Structure that is similar in unrelated organisms because it was evolved to do the same thing

Question 10

Allele frequency

Answer 10

How often an allele occurs in a gene pool

Question 11

Bottleneck effect

Answer 11

A population suddenly gets much smaller and the ones that survive are the ones that make up the new gene pool (natural disasters)

Question 12

Founders effect

Answer 12

A small group separates from the main group and starts a new population which now has a new gene pool

Question 13

Microevolution

Answer 13

Evolutionary change that occurs over a relatively short period of time

Question 14

Macroevoltion

Answer 14

Evolutionary change that occurs over geologic time above the levels of species

Question 15

Explain and give examples of the three types of selections

Answer 15

1. Stabilizing: Phenotypes at both extremes of the phenotypic distribution are selected against (Baby weight: Very large and very small are less likely to survive infancy)
2. Directional: Two extreme phenotypes are selected for (Beak size of the Galapagos finches)
3. Disruptive: When phenotypes in the middle of the range are selected against (sexual dimorphism - males and females have different heights, weights, and body shapes)

Question 16

What is the difference between micro and macro evolution? Examples of each?

Answer 16

• Micro: Occurs over a short period of time within a population of species (Evolution in the beaks of Darwin’s finches over the years)
• Macro: Occurs over a long period of time above the level of species (Fossil records show this - species will develop certain traits as they adapt to their environment (ex. Apes to humans))

Question 17

Explain how scientists use vestigial, analogous, and homologous structures to see how animals are related or share a common ancestor

Answer 17

• Vestigal: Evolution has reduced the size of the appendix because they are no longer used (used to be needed to digest food)
• Analogous: Wings of bats and birds function the same, but evolved independently in the two groups of animals (seen in the wing structure)
• Homologous: Inherited bone structures (like the forelimbs) from common ancestors but now function in different ways
• Scientists can look at these and see they are all similar, but also spot the differences between them to determine if the species share a common ancestor or not

Question 18

What is natural selection and how does it lead to changes in a population and adaptions? How des it affect allele frequencies?

Answer 18

• Natural selection: Process in whcih some living things produce more than others so the characteristics of organisms change over time
• There are more species so there is more competition - species are forced to adapt
• Some with certain dominant characteristics reproduce more than others, and if the bottleneck effect happens with a specific species over time different characteristics will appear more frequently

Question 19

Explain genetic drift, founders effect, and bottleneck effect, and be able to explain how each occur

Answer 19

• Genetic drift: A random change in allele frequencies that occurs in a small population (reproduction: allele frequencies in the offspring may differ from what was expected)
• Bottleneck: Population suddenly gets much smaller (natural disaster or hurricane)
• Founder: When individuals start a new population (Select number of people emigrate to an unfounded place)

Question 20

What is the Hardy-Weinberg equation? Solve for p and q

Answer 20

• Shows allele frequencies don’t change in a population if certain conditions are met
• P(2) + 2PQ + Q(2)

Question 21

What 4 effects did Darwin base his theories on?

Answer 21

1. Species produce many offspring
2. No one species has overrun the earth
3. Individuals must compete to survive
4. Only some survive the competition and are able to reproduce