Chapter 11: Forces Of Evolutionary

Question 0

Define evolution?

Answer 0

It is descent with modification. Descent implies inheritance and modification refers to change in heritable traits from generation to generation.

Question 1

How has our understanding of evolution changed?

Answer 1

Many scientist made significant contributions over the years, developing the foundation that Charles Darwin and Alfred Russell Wallace used to describe natural selection as the mechanism for evolution.

Gregor Mendel and Charles Darwin laid a foundation for evolutionary theory, but many scientists since that time have added to our understanding of how evolution works.

Question 2

Define population?

Answer 2

Consists of interbreeding members of the same species.

Question 3

Compare the theories of Aristotle, Lamarck, Buffon, and Darwin.

Answer 3

Aristotle- individuals in a species are basically identical and species are unchanging.

Lamarck- New species come from existing species through environmental forces.

Buffon- Species change as they spread from their original location.

Darwin- individuals in a population are different; species arise through the process of natural selection.

Question 4

Compare uniformitarianism and catastrophism.

Answer 4

Uniformitarianism is a theory proposed by James Hutton. It states that the processes of erosion and sedimentation that act in modern times have also occurred in the past, producing profound changes in earth over time.

George Curvier was convinced of catastrophism, the theory that a series of brief, violent, global upheavals such as enormous floods, volcanic eruptions, and earthquakes were responsible for most geological formations.

Question 5

How is the principle of superposition useful in tracing the history of life?

Answer 5

The principle of superposition is the idea that lower layers of rock (and the fossils they contain) are older than those above them.

Although curvier had to accept that some species must have become extinct, he refused to believe that they were not originally formed through creation.

Question 6

Explain the discredited idea of the inheritance of acquired traits.

Answer 6

Jean baptise de larmarck proposed the first scientifically testable evolutionary theory. He reasoned that organisms that used one part of their body repeatedly would increase their abilities.

Question 7

If larmarck was incorrect about the mechanism of evolution, is his contribution to our understanding of life’s diversity still important?

Answer 7

Yes it is.

Question 8

Discuss how Darwin’s readings of Lyell and Malthus influenced his ideas on life’s diversity?

Answer 8

Lyell renewed the argument for uniformitarianism in 1830. He suggested that natural processes are slow and steady, and that earth is much older than 6000 years. Lyell was so persuasive that many scientist began to reject catastrophism. Lyell work made Darwin an avid proponent of uniformitarianism.

Malthus principle on population stated that food availability, disease, and war limit the size of a human population.

Question 9

Discuss Darwin’s voyage on the HMS Beagle influenced his ideas on life’s diversity.

Answer 9

He recorded his observations as the ship journeyed around the coast of South America and noted forces that uplifted new land. He marveled at the forest plant fossils. Darwin tried to reconstruct the past from contemporary observations and wondered how each fossil had arrived where he found it.

Question 10

Explain descent with modification.

Answer 10

Darwin coined the phrase “descent with modification” to describe gradual changes from an ancestral type.

Question 11

How does Darwin use the term natural selection?

Answer 11

Darwin used the term natural selection to describe “this preservation of favorable variations and the rejection of injurious variations.”

Question 12

Compare artificial and natural selection.

Answer 12

Natural selection occurs when environmental factors cause the differential reproductive success of individuals with particular genotypes.

Artificial selection, a human chooses one or a few desired traits, such as milk production or seed size.

Question 13

Why does Darwin finally decide to publish The Origin of Species?

Answer 13

Darwin decided to publish because a lot of scientist approved of his theory.

Question 14

Explain the modern evolutionary synthesis?

Answer 14

It suggest that genetic mutations create heritable variation and that this variation is the raw material upon which natural selection acts.

Question 15

What is being synthesized?

Answer 15

The raw material upon which natural selection acts.

Question 16

Why do you think artificial selection of dog breeds has lead to unexpected and unwanted health problems in various breed of dogs.

Answer 16

Because the mixture of the breeds without checking the medical history of the animals parents can cause problems down the road.

Question 17

Define microevolution.

Answer 17

The relatively short-term genetic changes within a population or species.

Question 18

Define adaptations.

Answer 18

Features that provide a selective advantage because they improve an organisms ability to survive and reproduce.

Question 19

How is the term adaptation used in everyday conversation?

Answer 19

The word adaptation can be up confusing be aus it has multiple meanings, For example, a student might say, “I have adapted well to college life.” But short-term changes in an individual do not constitute evolution.

Question 20

How is the term used by scientist?

Answer 20

Scientist use adaptation in the evolutionary sense include only those structures , behaviors, or physiological processes that are heritable and that contribute to reproductive success.

Question 21

How does natural selection work on phenotypes and allele frequencies in populations?

Answer 21

Natural selection eliminates phenotypes.

Question 22

How does natural selection produce antibiotic resistant bacteria?

Answer 22

Natural selection requires preexisting variation. The presence of an antibiotic strongly selects for those bacteria that are immune to the drug.

Question 23

Why can no organisms have all the traits it might find useful.

Answer 23

Because evolution does not have a goal. No known mechanism allows the environment to tell DNA how to mutate and generate the alleles needed to confront future conditions. Nor does natural selection strive for perfection.

Question 24

What does survival of the fittest mean?

Answer 24

It means the individual is the one in the best physical shape to survive and reproduce.

Question 25

Define fitness?

Answer 25

Refers to an organisms genetic contribution to the next generation.

Question 26

Why is evolution inevitable in real population?

Answer 26

Because the environment is constantly changing.

Question 27

Define gene pool.

Answer 27

It’s entire collection of genes and their alleles.

Question 28

Define allele frequency.

Answer 28

One alleles frequency is calculated as the number of copies of that allele, divided by the total number of alleles in the population.

Question 29

Define Genotype frequencies.

Answer 29

Is the number of individuals with that genotype, divided by the total size of the population.

Question 30

What is the Hardy-Weinberg equilibrium?

Answer 30

Is the highly unlikely situation in which allele frequencies and genotype frequencies do not change from one generation to the next.

Question 31

When does Hardy-Weinberg equilibrium occurs?

Answer 31

It occurs only in populations that meet the following assumption: (1) mutations do not occur, so no new alleles arise; (2) individuals mate at random; (3) individuals do not migrate into or out of the population; (4) the population is infinitely large, or at least large enough to eliminate random changes in allele frequencies. (5) natural selection does not occur.

Question 32

When can frequency of an allele population change?

Answer 32

Radom mating, genetic drift, and natural selection influence the allele frequency within a population.

Question 33

If Hardy-Weinberg equilibrium is rare, why are you learning it?

Answer 33

The reason is that it serves as a basis of comparison to reveal when microevolution is occurring.

Question 34

What do the terms p, q, p2, 2pq, and q2 represent in the Hardy-Weinberg equilibrium?

Answer 34

W

Question 35

Why do allele frequencies always change in the real world?

Answer 35

Allele frequencies therefore always change over multiple generations. In other words, evolution is inevitable.

Question 36

Compare the three types of selection?

Answer 36

Directional selection- one extreme phenotype is fittest, and the environment selects against the others.

Disruptive selection- two or more extreme phenotypes are fitter than the intermediate phenotype.

Stabilizing selection- extreme phenotypes are less fit than the optimal intermediate phenotype.

Question 37

How are multiple alleles maintained in a population?

Answer 37

They maintain it through balanced polymorphism, in which multiple alleles of a gene persist indefinitely in the population at more or less constant frequencies.

Question 38

Define balanced polymorphism.

Answer 38

Multiple alleles of a gene persist indefinitely in the population at more or less constant frequencies.

Question 39

Define heterozygous advantage?

Answer 39

Which occurs when am individual with two different alleles for a gene has greater fitness than those whose two alleles are identical.

Question 40

Define sexual dimorphism?

Answer 40

Which is a difference in appearance between males and females.

Question 41

Define sexual selection?

Answer 41

Is a type of natural selection resulting from variation in the ability to obtain mates.

Question 42

Define gene flow?

Answer 42

Moves alleles among populations.

Question 43

How does genetic drift occur?

Answer 43

It occurs purely by chance.