Lab 3: Forces of Evolution and Population Genetics

Question 1

Forces of Evolution that cause frequencies of allele to change from one generation to the next

Answer 1

Mutation, gene flow, genetic drift, and natural selection

Question 2

Hardy Weinberg Equilibrium

Answer 2

When evolution in a population is NOT occurring; When the absence of evolutionary forces results in a lack of change in a population’s allele frequency from generation to generation

Has 4 conditions
Expressed mathematically with 2 formulas

Question 3

4 Conditions of Hardy Weinberg Equilibrium

Answer 3

1. No evolutionary forces active
2. Panmixia (population members mate randomly with respect to the allele in question)
3. The population is infinite
4. All population members produce the same number of offspring

Question 4

Cross generational sampling error

Answer 4

1 or 2 types of genetic drift; when frequency of an allele changes from one generation to another

Question 5

Macroevolution

Answer 5

Result of the accumulative effects of microevolution changes that occur over hundreds or millions generations

Dramatic enough to distinguish species from one another

Question 6

“Breeding” Population

Answer 6

The part of the population that gets considered in population genetics study

The people of reproductive age/capable of contributing to the gene pool

Reproductive boundaries/barriers for these groups aren’t always clearly defined (exp some cultures won’t intermarry; some specimens are separated geographically)

Question 7

Founder Effect

Answer 7

1 or 2 types of genetic drift; when a population subgroup becomes reproductively isolated from its parent groups and experiences reduced genetic variation compared to the parent group as a result

Includes population bottlenecks

Question 8

Speciation: Cladogenesis

Answer 8

When one species branches off from another species

Question 9

Speciation: Anagenesis

Answer 9

When one species evolved into another over time

Question 10

Speciation: Sympatric

Answer 10

When speciation happens even though all the organisms are in the same group in the same place

Question 11

Adaptive Radiation

Answer 11

When organisms adapt to fill open niches

Question 12

“Directional” Natural Selection

Answer 12

When a trait simply increases or decreased over time (like brain size) towards an EXTREME version of that particular trait

Question 13

“Stabilizing” Natural Selection

Answer 13

When a broad range of variations decreases/narrows towards the version that is most advantageous (like narrowed variety in cactus spine density); trait coverages into an IDEAL version

Question 14

Speciation: Allopatric

Answer 14

Most common; When speciation happens bc organisms from multiple populations are diverging in different places

Question 15

Gene Pool

Answer 15

Term for a population that described it as a collection of alleles

Question 16

Population bottlenecks

Answer 16

Part of founder effect; when genetic diversity in a group is low because its population is dramatically reduced in size but then increased again

Question 17

Evolution

Answer 17

Change in allele frequency from generation to generation

Question 18

Population Genetics

Answer 18

Branch of genetics that focuses on populations (not individuals) and how their genetics change over time, within a group/gene pool (collection of alleles in a group)

Question 19

Mutation

Answer 19

1 of 4 Forces of Evolution

Any change in a DNA sequence; Only source of NEW genetic variation

Common, random, and spontaneous

Some hurt, some are neutral, and others are advantageous

Question 20

Microevolution

Answer 20

Discrete/small scale, incremental allele changes that occur between generation to generation in a population

Question 21

Mathematical Eqns for Hardy Weinberg Equilibrium

Answer 21

recessive allele + dominant allele=1
p + q = 1

(frequency of homozygous dominant genetype)^2 + 2(frequency of heterozygous genotype) + (frequency of homozygous recessive genotype)
p^2 + 2pq + q^2=1. or (p+q)^2=1

Question 22

Genetic Drift

Answer 22

1 of 4 Forces of Evolution

Random change in allele frequency from one generation to the next d/t chance (including random impact of environment like a hurricane that kills all the green beetles but spares the brown ones)

Causes loss of variation; Has a bigger impact in small populations

2 types: Cross generational sampling error and founder effect

Question 23

Speciation

Answer 23

When so much adaptation occurs that a new species is formed; Requires reproductive isolation

2 types: anagenesis and cladogenesis

Question 24

Gene Flow

Answer 24

1 of 4 Forces of Evolution

When alleles enter a population from another population through sexual reproduction

Increases genetic diversity/variation within a population

Sometimes associated with physical migration of organisms

Question 25

“Disruptive” Natural Selection

Answer 25

When a trait increases or decreases in a way where an organism has little or no advantage over other members of the group (expressed mediocrity in beak size)

Question 26

Differential Fitness

Answer 26

R/t fitness (4th necessity of natural selection); the idea that some phenotypes will result in some organisms being able to survive longer and reproduce more than their less fit peers)

Ability to outcompete and out-reproduce

Question 27

Natural Selection

Answer 27

Follows from and results in adaptations that enable a species to better survive and reproduce in a given environment

Question 28

4 necessities of natural selection

Answer 28

Reproduction
heredity
variation among individuals
variation in fitness