Bio 152 chapter 21

as the horse family fossil record become more complete scientists realized that the evolution of horses was not linear, constant or unidirectional. Why?

-the rates of evolution varied through time with long periods of little or no change -change often occurred simultaneously across different lineages -in some lineages completely opposite trends occurred -

In_______ selection, humans choose the parents of the next generation, while in _________selection, organisms that survive and reproduce are those that pass their genes on.

1 .artificial 2. natural

Which of the following are recent observations that have challenged Tutt's hypothesis about peppered moths?

1. In some areas, evidence suggests that moths rest on leaves in the treetops, not trunks. 2. In some areas, lichens never changed even though dark moths became predominant. 3. Light moths in some areas increased in frequency long before lichens re-appeared.

Which of the following are common misconceptions about evolution that were traditionally thought to be revealed by the fossil records of horses.

1. Natural selection is a progressive guiding force pushing evolution in a single direction. 2.Evolutionary change is constant through time.

Which of the following are common misconceptions about evolution?

1. complex organs cannot be explained by evolution, but can be explained by intelligent design. 2. Evolution has not been demonstrated.

Structures that have evolved separately but look very similar exhibit ____________ evolution; in contrast, structures that evolved through modification from a common ancestral trait are _________________

1. convergent 2: homologous

The intelligent design argument cannot explain the presence of

1. vestigial structures 2. imperfect adaptations

What genetic phenomena may be responsible for unintentional selection?

1.Pleiotropy 2.Gene linkage

Which of the following (choose all that apply) have been suggested as hypotheses that may explain industrial melanism?

1.Surfaces in polluted areas get darker due to soot deposition. 2.Lichens decline due to pollution. 3. Pollution has toxic effects on light-colored moths.

Which of the following are reasons why island trees belong to plant families that typically do not have tree members (for example the sunflower family)?

1.Tree seeds rarely make it to isolated islands 2.The tree niche is empty and so a flower can evolve through natural selection to be

Even though there are gaps in the fossil record, some of the most direct evidence for evolution comes from fossils called ______ fossils that illustrate how certain major transformations in life forms occurred. Select all that apply.

1.intermediate 2.transitional

The feet of modern horses have ______toe(s); in contrast, early horses had_____ toe(s) on their front feet and______ toe(s) on their hind feet.

1: one, 1, a single, or single 2: four or 4 3: three or 3

Fossils that contain characteristics of two separate groups of organisms are called ________fossils.

1: transitional or intermediate

Why is it that some organisms do not appear to be perfectly adapted to their environment?

Because natural selection can only work on the variation present in a population.

Explain Darwin's observations on his Galápagos finches using the correct choice below.

Darwin initially identified some of the finches incorrectly.

How did Peter and Rosemary Grant show that the beak size of finches on Daphne Major is affected by natural selection?

In dry years, fewer small seeds were produced on the island and the average beak size of finches increased.

Why are giraffe necks not perfectly suited for their function?

Like all mammals, giraffes only have 7 vertebrae in their necks which limits their flexibility.

Species on islands often show great diversification; why?

The absence of many plants and animals means there are many unexploited niches

The reversal of melanism after the introduction of pollution control laws has been observed

in both Europe and North America

As a result of unexploited ecological niches, species arriving on islands often undergo great diversification over time leading to a phenomenon called_______ radiation.

adaptive

Examples from artificial selection clearly show that natural selection

can produce large differences between populations

The vertebrate _________ is an example of imperfect adaptation; this becomes very evident when it is compared with that of mollusks.

eye

Many fishes that inhabit the sub-freezing Arctic and Antarctic waters posses antifreeze proteins; we now know that there are at least five different kinds of antifreeze protein genes that have evolved independently in different species to perform the same function. This is an example of:

convergent evolution

In all cases when scientists have performed artificial selection experiments on fruit flies, a strong and predictable_____response has been observed.

genetic

Laboratory selection experiments have produced forms that cannot reproduce and thus would in nature be considered

different species

Some critics of evolution claim that because complex cellular mechanisms (for example, blood clotting) are ______, the intricate machinery of the cell cannot be explained by evolution from simpler stages. But this argument ignores the fact that natural selection operates on ______.

irreducibly complex; a system as a whole

The most commonly accepted hypothesis that explains industrial melanism and the reversal of industrial melanism is that

moths with coloration that matches their background are less susceptible to predation by birds

The primary process responsible for evolution is_______

natural selection

As a result of convergent evolution, many marsupial mammals of Australia look similar to_________ mammals found elsewhere and occupy a similar ecological niche.

placental

The teeth of early members of the horse family (for example, Hyracotherium) were

small and relatively simple

Attempts to domesticate silver foxes by artificial selection resulted in the ________selection of traits which produced silver foxes that were as tame as domestic dogs.

unintentional

Unintentional selection can be the result of linkage and______

pleiotropy

Molecular analysis of lactase DNA__________ in humans shows that genes for that enzyme have __________evolved in Africa and Europe to produce the same result.

Blank 1: sequences Blank 2: independently or separately

When did humans begin to utilize artificial selection?

Centuries and millennia ago.

Typically, how are species on islands related to species on a nearby continent?

More closely

What is the current explanation, from an evolutionary standpoint, of the lack of large placental mammals in Australia?

Placental mammals evolved elsewhere and could not disperse to Australia due to its isolated position in the ocean.

How has rock and fossil dating changed since Darwin's times?

Relative dating was used in the past; today we use absolute dating.

What recent observation has prompted scientists to challenge Tutt's hypothesis about the cause of industrial melanism?

Reversal of industrial melanism is not correlated with the re-appearance of lichens.

Which of the following is not an example of an imperfect adaptation?

The human coccyx

The observation that the relative frequencies of melanic to light peppered moths changes with the color of tree bark provides support for

The observation that the relative frequencies of melanic to light peppered moths changes with the color of tree bark provides support for

How are traits produced by convergent evolution different from homologies?

Traits produced by convergent evolution have not evolved from a common ancestral trait, while homologies have.

One of the best studied examples of evolutionary change is that of the Blank ______ family. This family includes zebras and donkeys, among other animals.

equine or horse

The forelimbs of modern vertebrates are homologous structures, meaning that they may have changed evolutionarily to perform different functions, but they

evolved from the same body part in a common ancestor.

Evolution is supported by a substantial body of evidence and explains a wide range of observations, thus it is considered a scientific_____

theory