Evolution mini exams

HIV infections can last for years without causing illness. Influenza (flu) infections normally only last a few days to weeks. What is your expectation of the genetic diversity of HIV vs flu viruses within individual patients.

HIV will be more genetically diverse within patients than influenza

Why is human diet a major health concern today from an evolutionary perspective?

Human diet has changed very rapidly and humans have not adapted to our new diet

How is eusociality different from 'regular' cooperative breeding

In eusocial organisms there are permanent groups of non-breeding individuals

Which of the following pairs of structures is similar only due to convergence with no similarity due to common ancestry. See information below. Bat wings are modified front legs (vertebrates) Bird wings are modified front legs (vertebrates) Insect wings are novel structures that are not modified from anything previously existing in the insect body Flying fish 'wings' are modified pectoral fins (front pair of fins)

Insect and bird wings

The phylogeny below shows the relationships of several fossil taxa of arthropods. Each number represents the evolution of a specific trait. 1 is compound eyes, 2 is jointed appendages and 4 is a jointed body. Which organism would you expect to have traits 1 and 2 but not 4

Isoxys

You are studying the adaptation of killifish to a brackish (part salt/part fresh) water environment. You discover that killifish living in a bay (brackish) have a different version of an enzyme compared to stream (fresh water) killifish. Previous mark recapture studies have indicated these fish are highly mobile and frequently disperse fairly long distances. The killifish are also easily maintained in the lab. What would be a practical approach to testing ideas about adapation?

Laboratory selection experiments where salinity is changed and evolutionary responses observed in captive populations

What phenomenon explains the following data? Virus 1 - 100 Kb genome, 99 Kb protein coding Virus 2 - 1 Mb genome, 998 Kb protein coding Bacterium 1 - 5 Mb genome, 4.9 Mb protein coding Bacterium 2 - 11 Mb genome, 10.8 Mb protein coding Plant - 5000 Mb genome, 15 Mb protein coding Fungus - 50 Mb genome, 11 Mb protein coding Grasshopper - 500 Mb genome, 18 Mb protein coding Snake - 1200 Mb genome, 19 Mb protein coding

Large amounts of non-coding DNA in eukaryotes

A new species of archaean prokaryote is found living a hot spring. When a scientist sequences its genome in an attempt to discover its evolutionary relationships she discovers something strange. Most of the genome is similar to the genomes of several well known archaean species. However one enzyme is very similar to that found in a species of bacteria that also lives in hot springs. The enzyme does not have a function related to living in hot springs. What is the most likely explanation for this similarity in the enzymes.

Lateral gene transfer between the bacterium and the archaean

Mangroves are trees adapted for living in salt water. Data from genes unrelated to mangrove adaptations indicate that the mangrove way of life has evolved separately in several different plant families. Analysis of the development of mangrove traits such as 'live birth' and salt metabolism indicates that they are performed using the same molecular mechanisms in the different types of mangroves (i.e. based on the mechanisms they would appear to be homologous traits). What is your interpretation of these findings.

Natural selection acted on the same genetic architecture independently in each taxon

Based on the phylogeny below what is the sister taxon of the orange?

Papaya

Which of the three components of the Breeder's equation represents evolutionary change?

R

A small population (10 individuals) of eels lives in an isolated swamp. At the C locus there are two alleles C1 and C2 with frequencies 0.6 and 0.4. Genotypes C1C1, C2C2, C1C2 all have equal fitness. Which of the following is not likely to happen in this situation?

The allele frequencies stay constant over time.

A new viral disease is discovered. It is highly infectious through close human contact. Infected individuals become very sick and no longer able to walk within an hour of infection and die within a day. What is a likely outcome of the appearance of this disease?

The disease kills a limited number of people but is contained through quarantive

What does the image below tell you about the effect of genes and the environment on this trait?

both genes and the environment have strong effects

Which type of fossil is three dimensional but only preserves the external details of the structure?

cast/mold

Which type of test can look at the origin of an adaptation

comparative study

In many primates indivduals groom one another and remove parasites, dirt, etc. The individual being groomed gains a cleaner coat and loss of parasites. The groomer may gain a small amount of food but does spend quite a bit of time and energy in grooming. All individuals act as both groomers and groomees. This type of social interaction is ...?

cooperation

Heterozygote advantage produces a stable equilibrium because the rarer of the two alleles is present mostly heterozygotes and is thus more successful. As this allele then becomes more common it present less often in heterozygotes and it thus less successful. This is a special case (example) of which of the following?

frequency dependent selection

A time traveller from 1900 arrives in your lab where you are studying the inheritance of human height. The time traveller tells you that height can't be inherited through genes because it doesn't follow a standard Mendelian pattern of inheritance. How do you respond?

height is influenced by many genes as well as the environment

Which mechanism of evolution is most likely to prevent the speciation process from proceeding between two populations?

high gene flow between populaitons

In which situation is high linkage disequilibrium a signal of strong selection favoring the allele?

in alleles at high frequency

In general prokaryotic cells have a lower mutation rate than viruses (which have smaller overall genomes). What is the explanation for this pattern? Why does this pattern not hold true for eukaryotes?

increasing selection against mutation with increasing genome size/negative correlation between genome size and effective population size

In birds which of the following statements about the evolution of cooperative breeding is true

it is positively associated with genetic monogamy in females

Which of the following is NOT a characteristic of the fossil record supporting evolution?

many fossils are unique to particular locations

A common pattern in insect diversity is that there are groups of species that appear very similar to one another except for the structure of their genitalia. In particular, the male genitalia (which are external and thus more obvious) are ofte used as the characteristics that define each species. Based on this evidence what type of isolation is keeping these species separate from one another?

mechanical

A species of grasshopper occurs on an island and on the mainland nearby. The mainland habitat is dry grassland and the grasshoppers are all brown in color, caused by the B1 allele. The island is forested and the grasshoppers are mostly green in color, caused by the B2 allele. However, there are a number of brown grasshoppers on the island at all times, despite the fact that they have low fitness there (they are eaten by birds much more commonly than green grasshoppers). Which evolutionary force is maintaining the brown grasshoppers on the island? Both the mainland and island have large populations of grasshoppers.

migration

An allele is common in a population of Tasmanian Devils. This allele causes a reduction in fitness (reproduction and survivorship) in Tasmanian Devils over the age of 10. Relatively few TDs survive to age 10 in nature due to disease and accidents. The allele has no effect on fitness at younger ages. The presence and abundance of this allele can be explained through the ________ hypothesis. If probably rose in frequency due to ___________.

mutation accumulation, genetic drift

It is estimated that every human carries at least one recessive lethal allele (i.e. they are heterozygotes at that locus). What maintains these alleles in populations given their lethality when homozygous?

mutation/selection balance

Which of the following is a likely outcome of natural selection acting on a population of cancer cells?

mutations that cause cells to reproduce faster will increase in frequency

Which technique cannot be applied to morphological data to estimate a phylogeny?

neighbor joining (distance tree)

Which multicellular organism below would lack HOX genes?

palm tree

Which structures are thought to be possibly similar to the earliest forms of life?

ribozymes

Which evolutionary force is based on fitnesses differences between alleles and genotypes?

selection

A scientist is studying the structure of an enzyme that synthesizes the molecule keratin in armadillos. They have DNA samples of the gene in two armadillo species as well as samples of the enzyme itself. The DNA samples differ quite a bit (i.e. there are quite a lot differences in the nucleotide sequence). However, the enzyme is almost exactly the same (in terms of amino acid sequence) in the two species. What does this imply about selection on the enzyme?

selection has prevented change in the enzyme

You have a population of 500 individuals at which p=q=0.5 at the A locus (e.g. the frequency of A1 and A2 are both 0.5). The population starts in Hardy Weinberg. Which of the following would cause an immediate and large increase in the proportion of homozygous individuals in the population?

selfing

Which of the following terms describes the types of traits used in estimating phylogenies?

synapomorphy

A clade (monophyletic group) of fungi is studied that contains about 40 species. Four of the species of fungi in this group have the interesting property of secreting a protein that anesthetizes small animals so that the fungus can consume them. The protein is very similar to an existing protein found in all the fungi. A phylogeny of the anesthetic and non-anesthetic protein finds the all four anesthetic proteins are similar and form a clade. However a phylogeny of the fungi using a bunch of other genes finds that the four fungus species with the anesthetic protein are not closely related and in each case their sister taxon is a species with the non-anesthetic protein. What is the most likely conclusion can you make about the evolution of the protein?

the anesthetic version of the protein evolved independently four times

It has been hypothesized that the coat patterns of baby giraffes may influence their survival rates. Specifically, giraffe calves are more likely to evade predators (such as lions and hyenas) if their coat patterns help them to blend into their environment. Different coat patterns are more effective in different environments. Some members of a population of giraffes disperse from an open grassland (very few trees or shrubs) to a dense forest (many trees or shrubs). The color and patterning of the ground cover are very different. What do you expect to happen?

the color pattern should diverge due to natural selection as long as migration between the populations is low

The Trim(alpha) gene can provide protection from viruses that attempt to bind to cell membranes in humans. However, the common allele of Trim(alpha) in humans does not work very well against HIV. What is the probably explanation for this?

the common Trim(alpha) allele evolved to defend against a now extinct virus

What limits the life time reproductive success of organisms and dictates tradeoffs between life history characteristics? Pick the best answer.

the finite amount of resources available to organisms for reproduction, growth and maintenance

A key observation in the study of molecular evolution was that there is an inverse relationship between generation time and population size across organisms. This inverse relationship is necessary to explain which of the following?

the molecular clock

In this hypothetical example, a mutant frog is found in a laboratory population. It has several phenotypic differences compared to typical frog including hypno vision, wings, and huge fangs. Which of the following is not a reasonable explanation for this mutant having so many phenotypic differences?

the mutation is dominant

The examples of rapid speciation being observed in nature were of insects that were feeding specialists on particular types of plants and stickleback fish moving into lakes. What do these examples have in common?the o

the organism entering a new enviroment

Which of the following statements accurately describes methodical naturalism

the supernatural may or may not exist but science can only address hypotheses based on natural explanations

What is a potential problem with the Grant's work on natural selection and evolution in Darwin's finches?

their estimates of heritability may be biased by common environments

The scientist Carl Woese discovered the ______ of life through molecular systematics. These groups became distinct from one another over 2 billion years ago. Discovering evolutionary relationships further back than that may not be possible due to extensive _______.

three domains, lateral gene transfer

Which of the following is NOT necessary for natural selection to occur?

trait must have a genetic basis

Which of the following is the best way to treat a disease without causing the evolution of resistance in the organism causing the disease?

use multiple drugs at high doses

A scientist speculates that fish that have larger clutches of eggs should be able to breed less frequently because a tradeoff (i.e. the more energy you put into offspring the longer you have to wait to build up more energy). However when she does a field study of catfish she finds the opposite. Individuals with larger clutches actually produce clutches more frequently. What is this not an unexpected outcome?

variation in health and vigor due to the environment are masking the tradeoff

Which of the following is NOT a life history trait?

wing length

The figure below shows a phylogeny of arthropod groups. The possible options are four possible combinations of taxa that could be given names as taxonomic groups. Only one of the combinations is monophyletic? Which one?

"Crustacea" and Insecta

A crocodile enthusiast in Australia has a large population of saltwater crocs in captivity. One day she discovers an albino crocodile in a clutch of new hatchlings. She carefully monitors the population over the next few years and finds 10 albino crocodilians out of a total of 1000. Albinism is caused by a recessive allele. Assume the population is in Hardy Weinberg. What is the frequency of the albino allele.

0.1

After some breeding experiments you have calculated the following values for sugar content in grapes. Phenotypic variance = 24.00 Genetic variance = 8.00 Additive genetic variance = 6.00 Dominance variance = 2.00 What is the narrow sense heritability?

0.250

The idea of descent with modifications (evolutions with splitting) indicates that species should first appear in the same geographic location as their immediate ancestor. Which general patterns of the geographic distributions should you see as a result of the above? 1. closely related species should usually occur in the same ares 2. groups of organisms may be absent from environments in which they can live, if those environments are far from the region in which the group originated 3. similar organisms should be found in similar environments worldwide 4.Islands should have more species than mainland habitats

1 and 2

Which of the following techniques were used to estimate the approximate date of origin of HIV. 1. Radioactive carbon dating 2. Phylogeny of SIV to determine the species of HIV origin 3. Phylogeny of HIV to estimate ancestral sequence 4. Estimating rate of change in HIV to extrapolate back in time. 5. Study of extinct viruses in human

3 and 4

Isotope X has a half life of 1,000,000 years. Isotope X exists at a concentration of 8% in living tissue. A fossil has a concentration of 1%. Approximately how old is the fossil?

3,000,000 years

Why are pathogens that require direct contact between hosts less virulent than those transmitted by other means?

A highly virulent pathogen would incapacitate the host

Which of these trees best represents the relationships you would expect to see if these populations are different species?

B

In florida scrub jays individuals often help at the nest of their parents. There is limited breeding habitat for this specialist bird and the chance of breeding on their own is very low. Which of the statements about Hamilton's rule (rB>C) is the best explanation for cooperative breeding in this species?

C is very low relative to most birds

You find a fossil while out on hike. You forget what time period the rock in the area is from (you were having a nap during that lecture in geology) but you remember that the rock is from marine sediments. The fossil is fairly small but shows a complex animal that doesn't resemble any of the animal phyla you studied in your animal diversity course. This fossil is probably from which period?

Cambrian

A scientist is interested in the source of variation in body size in mice. He has four genetic strains of mice that are all living in identical cages in the same room. He measures them and finds that the strains all have the same average body size. One of the strains is also being kept in a different room with a colder temperature*. The mice in that room are significantly larger. He concludes that body size variation in mice is solely due to the environment. Is this correct? Why or why not?*The parents of these mice were ordered from a supplier and the offspring grew up in the rooms they are in now.

Can't Tell. Genotype by environment variation has not been tested

Which of the following people would have influenced Darwin's thinking about the age of the earth and the time available for evolution?

Charles Lyell