Chapter 15: Processes of Evolution

Question 1

What is evolutionary theory?

Answer 1

It is a bundle of theories

Question 2

Who was Jean Baptiste Lamark?

Answer 2

He was an evolutionary biologist that studied the evolution giraffes neck.

Question 3

Charles Darwin was the first of what?

Answer 3

He was the first one to articulate a plausible mechanism for evolution that was derived from different fields of study.

Question 4

What is Thomas Robert Malthus known for?

Answer 4

Population growth is potentially exponential while the growth of the food
supply is linear. Only a fraction of any population will
survive and reproduce.

Question 5

Uniformitarianism Theory

Answer 5

is the assumption that the same natural laws and processes that operate in our present-day scientific observations have always operated in the universe in the past and apply everywhere in the universe

Question 6

What did Darwin do in 1831?

Answer 6

He began a 5-year voyage around the world on a

Navy survey vessel, the HMS Beagle.

Question 7

What did Charles Darwin discover during his five-year journey?

Answer 7

The finches beaks were all different from each other and had different functions

Question 8

What are the three thories Darwin made up?

Answer 8

1. Species change over time due to environmental changes
2. Divergent species share a common ancestor
3. The mechanism that produces change in natural selection (testable)

Question 9

What is the essence of Darwin’s natural selection theory?

Answer 9

1. Heritability (it has to be passed on)
2. Variation is needed to evolve
3. competition for survival of species

Question 10

Why is natural selection so important?

Answer 10

It is the first evolutionary theory that could be tested

Question 11

What does the evolutionary term “Fitness” refer to?

Answer 11

It refers to the individual’s ability to leave an offspring and allows the individual to survive and reproduce

Question 12

What is evolutionary fitness?

Answer 12

It is the number of offspring plus the number of future descendants

Question 13

Indirect fitness/inclusive fitness

Answer 13

An indirect way for an organism to pass on their genes from a sibling who has an offspring

Question 14

What is adaptation in terms of evolution?

Answer 14

The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to an environment.

Question 15

What are the two simple rules of Natural Selection?

Answer 15

1. Evolution doesn’t have to be elegant, it just has to work

2. evolved organisms can have defects as long as they can still survive and reproduce

Question 16

What is modern synthesis?

Answer 16

describes the fusion (merger) of Mendelian genetics with Darwinian evolution that resulted in a unified theory of evolution

Question 17

Population

Answer 17

a group of individuals of a single species that live and interbreed in a particular geographic area at the same ti time

Question 18

Mutations

Answer 18

1. Occur randomly

2. Can be deleterious, beneficial, or neutral (have no effect)

Question 19

Deleterious

Answer 19

Something that can kill

Question 20

Recombination

Answer 20

is a process by which pieces of DNA are broken and recombined to produce new combinations of alleles

Question 21

Gene Flow

Answer 21

Migration or mating of individuals between populations that introduces variation

Question 22

Genetic Drift

Answer 22

is a mechanism of evolution in which allele frequencies of a population change over generations due to chance (sampling error). It is faster in smaller population

Question 23

Population Bottlenecks

Answer 23

occur when a random disaster occurs and a few individuals survives (passes through a narrow neck of a bottle)

Question 24

Founder effect

Answer 24

Occurs when new individuals that find a new place to live and colonize (special bottleneck)

Question 25

Allele Frequencies

Answer 25

refers to how common an allele is in a population. It is determined by counting how many times the allele appears in the population then dividing by the total number of copies of the gene.

Question 26

Gene Pool of a Population

Answer 26

consists of all the copies of all the genes in that population

Question 27

Genotype Frequencies

Answer 27

shows how a population's genetic variation is distributed among its members

Question 28

Biological evolution

Answer 28

Refers to changes in the genetic makeup of populations over time

Question 29

Sexual Selection

Answer 29

Occurs when individuals of one sex mate preferentially with a particular individual of the opposite sex

Question 30

Hardy-Weinberg Equilibrium

Answer 30

allele frequency = the number of copies of the allele in the population divided by the total number of copies of all alleles in the population

Question 31

What are to conditions that must be met for a population to be at Hardy-Weinberg Equilibrium?

Answer 31

1. There is no mutation 2. There is no selection among genotypes 3. There is no gene flow 4. Population size is infinite 5. Mating is random

Question 32

Qualitative traits

Answer 32

``` influenced by alleles at one locus; often discrete qualities (black vs white, smooth vs wrinkled). ```

Question 33

Quantitative traits

Answer 33

influenced by alleles at more than one | locus; likely to show continuous variation (body size)

Question 34

Stabilizing selection

Answer 34

Acts to reduce variation without changing the mean value of a trait (birth weight)

Question 35

Directional selection

Answer 35

Acts to shift the mean value of a trait toward one extreme ( Texas Longhorn cattle)

Question 36

Disruptive selection

Answer 36

favors both extremes of trait values, resulting in a bimodal character distribution ( bill size in the black-bellied seedcracker of West Africa.)

Question 37

The Paradox of Sex

Answer 37

Sexual reproduction results in new combinations of genes and produces a genetic variety that increases evolutionary potential.

Question 38

Purifying Selection

Answer 38

Selection against any deleterious mutations to the usual gene sequence

Question 39

What are the disadvantages of the paradox of sex?

Answer 39

1. Recombination can break up adaptive combinations of genes 2.Reduces the rate at which females pass genes to offspring 3. Dividing offspring into genders reduces the overall reproductive rate

Question 40

Muller's ratchet

Answer 40

In the absence of genetic recombination, deleterious mutations accumulate with each replication

Question 41

Sexual recombination does not directly influence the | frequencies of alleles. Rather, what does it do?

Answer 41

it generates new combinations of alleles on which natural selection can act.

Question 42

Synonymous substitution

Answer 42

don’t affect phenotype because most amino acids are specified by more than one codon

Question 43

Nonsynonymous substitution

Answer 43

changes the result of amino acids and can be deleterious, selectively neutral, or (more rarely) advantageous

Question 44

pseudogenes

Answer 44

copies of genes that are no longer functional

Question 45

Lateral Gene Transfer

Answer 45

individual genes, organelles, or genome fragments move horizontally from one lineage to another. this can be advantageous to species