Exam 5 - Biology 1010 - Durbak Mizzou

A mutation in which of the following cell types could be passed on to children? A. Brain B. Skin C. Gamete D. Heart E. All of the above

C

What type of mutation could result in a significantly SHORTER protein? A. Spontaneous B. Missense C. Frameshift D. Silent

C

A large population of animals is split in two by a physical barrier. Over time, the genetic makeup of the two resulting populations becomes more and more different until each population becomes a separate species. This is an example of A. Natural selection B. Gene flow C. Genetic drift D. Allopatric speciation E. Sympatric speciation

D

What defines a group of humans as a population? A. Interbreeding members of the same species at the same place and time B. Multiple species interacting together C. Members of a species in the same place and time D. Members of the same group that share a common ancestor

A

Homology is evidence of A. Artificial selection B. Common ancestry C. Binomial classification D. Natural selection

B

Which of the following would NOT be expected after a population undergoes geographic isolation? A. A decrease in gene flow B. Allopatric speciation C. Natural selection D. An increase in gene flow

D

In the Great Plains, corn plants that are too short fail to get enough sunlight and die quickly, while very tall plants tend to be uprooted by wind very easily. Thus, plants with a median height are the most likely to survive and reproduce. What type of selection is most likely to occur in the Great Plains population of corn plants? A. Natural selection B. Diversifying selection C. Stabilizing selection D. Directional selection E. Artificial selection

C

A zombie apocalypse wipes out almost the entire human species before the zombie threat is eliminated. Only a group of 100 people who were at a family reunion on an uninhabited island survived. They returned to the mainland completely unaware of what had happened to everyone. What form of genetic drift has occurred as a result of the zombie apocalypse? A. Gene flow B. Founder effect C. Genetic drift D. Bottleneck effect E. Natural selection

D

A zombie apocalypse wipes out almost the entire human species before the zombie threat is eliminated. Only a group of 100 people who were at a family reunion on an uninhabited island survived. They returned to the mainland completely unaware of what had happened to everyone. A non-zombie straggler with green eyes stumbles onto the last remaining human outpost. The green eye allele did not exist in the population before her arrival, but it does now. What is the name of this mechanism of evolution? A. Bottleneck effect B. Gene flow C. Founder effect D. Genetic drift E. Natural selection

B

Suppose that green eyes require a person to be homozygous recessive for the G gene. Assuming that everyone else in the population (total 101 people) is homozygous dominant for the gene that causes green eyes, what is the allele frequency of g? A. 2/202 B. 4/202 C. 2/101 D. 4/101

A

Which of the following is NOT an example of artificial selection? A. Using the winner of the Triple Crown horse races to produce new horses B. Breeding strains of corn that contains resistance to viruses C. Mating poodles with Maltese dogs to reduce shedding D. Letting your corn plants be pollinated randomly by bees

D

Both bats and birds have wings that allow them to fly, but they do not share a common ancestor. What type of trait would their wings be considered? A. Natural selection traits B. Analogous traits C. Convergent traits D. Homologous traits

B

Do antibiotics create resistant strains of bacteria? A. No, to become resistant to antibiotics, individual(s) in the population must randomly mutate, and that mutation, if heritable, causes the bacterial population to become resistant to antibiotics B. No, antibiotics can only work on the strain the were tested for C. Yes, overexposure to antibiotics causes the protein on the surface of the bacteria to change D. Yes, overuse of antibiotics causes the DNA of bacteria to mutate making the bacteria resistant

A

Two populations of squirrels are geographically isolated from each other when a river forms. The two populations develop morphological differences. After 100 years, the river changes course and the two populations move into the same area. Which of the following would indicate the two populations most likely represent two separate species? A. The populations maintain morphological differences even though they are in the same area B. 100 years is not long enough time for speciation to occur, so they must still be a single species C. A DNA analysis indicates significant genetic differences between the two populations D. The two populations interbreed and produce fertile offspring

C

In a population, at generation 0, B=0.5 and b = 0.5, while after 50 generations, B = 0.75 and b = 0.25. What can be said about this population? A. The frequencies have remained constant B. It has remained free from evolutionary forces C. It has evolved D. The population size has increased.

C

In many predator-prey relationships, evolutionary change in the prey will result in evolutionary change in the predator, a phenomenon known as A. Convergent evolution B. Sympatric speciation C. Homology D. Coevolution

D

Which of the following methods are used to gather evidence for how life has evolved? A. Molecular biology B. Biogeography C. Comparative anatomy D. Paleontology E. All of the above

E

Which of the following could cause a population to evolve? A. Preventing new individuals from coming into the population B. Being exposed to a strong mutagen C. A very large population D. Preventing related individuals from mating

B

mutation

change in the nucleotide sequence of DNA, Arise when nucleotides are substituted, deleted, or inserted within a gene.

How do new alleles arise in a genome?

Through mutations

What is a spontaneous mutation?

* Mistakes can occur during DNA replication * DNA polymerase adds the wrong nucleotide or accidentally adds in extra or too few nucleotides • Cells contain enzymes whose function is to ‘proof-read’ DNA sequences and fix mistakes in sequence

How does an induced mutation occur?

through chemical mutagens, radiation, infectious agents

somatic mutation

occurs in a body (nongamete) cell and is not passed on to offspring • passed only to daughter cells of mutated cell • sporadic mutation

germ-line mutation

occurs in gametes and are passed on to offspring. • In every cell of the offspring’s body • Heritable mutations

silent mutation

no change to the amino acid- codon codes for the same amino acid

missense mutation

wrong/different amino acid is coded for

How do missense mutations affect proteins?

they can change the structure and function of the protein by causing it to fold incorrectly

nonsense mutation

when a stop codon occurs prematurely

frameshift mutation

Removing a nucleotide causes a shift in which 3 nucleotides are read as codons, makes the protein strand shorter

Changing 1 nucleotide can...

• change an amino acid • change a protein’s shape • prevent the protein from functioning

evolution

change over time

population

a group of organisms of the same species living together in the same geographic area

artificial selection

organisms of the same species that contain desirable traits are continually bred into individuals that don’t have the trait

natural selection

process by which individuals with advantageous inherited characteristics for a particular environment survive and reproduce at a higher rate than those lacking that trait

directional selection

shifts the overall makeup of a population by selecting for one extreme phenotype

stabilizing selection

favors intermediate phenotypes

Diversifying (disruptive) selection

leads to two or more contrasting phenotypes in a population

gene pool

total collection of alleles in a population

allele frequency

the relative proportion of an allele in a population

What causes allele frequencies to change?

1. Mutation introducing new alleles into the population 2. Natural selection favoring some alleles over others 3. Non-random mating 4. Movement of alleles from neighboring populations 5. A small population size

inbreeding

•Mating between closely related individuals •Increases the proportion of homozygous individuals compared to heterozygotes

gene flow

occurs when genetic exchange occurs with another population

genetic drift

change in allele frequencies between generations that occurs purely by chance • Due to reductions in population size • Deviations of allelic frequencies are random, therefore the direction of change is unpredictable. • Reduces diversity

bottleneck effect

a type of genetic drift that occurs when a population is suddenly reduced to a small number of individuals, and alleles are lost from the population as a result.

founder effect

a type of genetic drift in which a small number of individuals leaves one population and established a new population. • By chance, the newly established population may have lower genetic diversity than the original population

why is genetic diversity important?

•Genetic drift often results in loss of genetic diversity (loss of alleles in a population) •Diverse gene pool gives a population more flexibility to survive in a changing environment •The more genetically diverse a population, the more ways it has to adapt

descent with modification

(Darwin’s “evolution”) •All living things are related •Different species emerged over time due to natural selection humans are unique as species, but we share characteristics (DNA) with other species

fossil

the preserved remains or impressions of once-living organisms

fossil record

an ordered sequence of fossils as they appear in the rock layers, marking passage of geologic time

paleontologist

studier of fossils

plate tectonics

the continents and seafloors form a thin outer layer of solid rock that is divided into irregularly shaped pieces that float atop a viscous underlying layer

biogeography

the study of the past and present distributions of organisms

comparative anatomy

•Comparison of body structure between different species •Provides evidence that evolution is a remodeling process in which ancestral structures become modified to take on new functions

homology

similarity due to common ancestry

homologous structures

similar structures because they are inherited from the same ancestor

vestigial traits

are structures that some species contain that serve no function, but are inherited from a common ancestor

convergent evolution

results in organisms that have similar traits/appearance, but lack a recent common ancestor

analogous traits

When species share traits due to convergent evolution (so are not genetically similar)

evolutionary trees

illustrate patterns of descent using similarity between either anatomical characteristics or molecular (DNA) characteristics

Biological species concept

defines a species as a groups of populations whose members have the potential to interbreed with one another in nature and produce fertile offspring.

reproductive barriers

anything that prevents individuals of closely related species from interbreeding

speciation

the process in which one species splits into two or more species

genetic divergence

when too many differences in the DNA accumulate between populations

reproductive isolation

When populations can no longer interbreed

allopatric speciation

•When new species arise in populations that geographically isolated (physically separated)

ecological isolation

when two closely related species are reproductively isolated by differences in habitat (can be small or large differences)

coevolution

When two species interact with each other so much that the evolution of one species pushes the second species to evolve at the same time

sympatric speciation

populations that are present in the same geographic location will undergo speciation •Occurs when there are reproductive barriers, which is anything that can prevent two individuals from successfully producing offspring •Can be prezygotic or can be postzygotic

prezygotic barriers

includes anything that prevents mating or fertilization

temporal isolation

mating behavior or fertility occur at different times

behavioral isolation

different mating activities

gametic isolation

gametes cannot unite

mechanical isolation

mating organs are incompatible

postzygotic barriers

after interspecies mating occurs, if hybrids zygotes fail to survive or reproduce

hybrid invariability

gametes unite but viable offspring cannot form

hybrid infertility

viable offspring cannot reproduce