How are adaptations beneficial to organisms?
Adaptations help organisms survive and reproduce in a particular environment
Why was Darwin's acceptance of an ancient, continuously changing Earth so important in his development of his ideas about evolution?
Darwin hypothesized that species changed gradually, over long spans of time, in response to diverse and changing habitats
An adaptation is:
a heritable trait that confers a reproductive advantage on the individual possessing it
At the time Darwin voyaged on HMS Beagle, the popularly accepted theory in Europe that explained the origin of Earth's plants and animals held that the various species:
had been created rapidly by a divine creator a few thousand years before
What broad set of ideas was established by the work of Lamarck, Lyell, and Darwin?
Earth and its life are ancient and ever-changing; fossils document the evolution of life-forms over time
Blue-footed boobies have webbed feet, and are comically clumsy when they walk on land. Evolutionary scientists view these feet as:
the outcome of a tradeoff: webbed feet perform poorly on land, but are very helpful in diving for food
Lyell's book Principles of Geology, which Darwin read on board the HMS Beagle, argued in favor of which concept?
Earth's surface is shaped by natural forces that act gradually and are still acting
In artificial selection, humans provide the selective pressure for species to change and shape the evolution of various breeds. What provides the selective pressure in natural selection?
German shorthaired pointers, Scottish terriers, and Beagles are capable of interbreeding and producing viable, fertile offspring. The diversity seen in these breeds of dogs is the result of:
If members of a population have traits that are both heritable and variable among individuals, then:
advantageous traits will probably become more widespread in subsequent generations
Darwin inferred that there is a struggle for existence in which each individual's odds of surviving to reproduce are quite poor, based on the observation that:
natural population sizes usually stay about the same over long periods of time
In natural selection, ____ determine which phenotypes are successful.
current conditions in the local environment
A number of mosquito populations today are resistant to specific insecticides that once were effective in killing them. Biologists believe that insecticide resistance evolved in mosquitoes because:
a few mosquitoes were probably resistant to the insecticide before it was used. These survived to reproduce and now the norm in populations that have been exposed to the chemical
What summarizes the order of appearance of major life-forms and the time at which life first appeared as documented by the fossil record?
prokaryotes, unicellular eukaryotes, multicellular eukaryotes, with the oldest life-forms appearing about 3.5 billion years ago
What best describes the fossil record?
the highly ordered sequence in which fossils are found in layers of sedimentary rock
Evidence from molecular biology supports the theory of evolution by showing that:
diverse organisms share many similar genes and proteins, and the similarity of these molecules is greatest when comparing closely related organisms
All known organisms use genetic information to produce protein molecules via the same genetic code. This finding strongly supports the hypothesis that:
all organisms are descended from one or a few common ancestors
The bones of the wings of bats are homologous to the bones of the____ of their ancestors.
Organisms that possess homologous structures probably:
share a common ancestor that also had this structure
Microevolution, or evolution at its smallest scale, occurs when:
a population's allele frequencies change over a span of generations
The ultimate source of all new alleles is:
mutation in parent cells (asexual organisms) or in cells that produce gametes (sexual organisms)
Scientists have warned doctors of the danger of their increasing use of antibiotics for treating minor illnesses. They are concerned because:
strains of bacteria that are resistant to these drugs will become more widespread
Which genotype relative to the sickle-cell allele has the greatest reproductive success in regions where malaria is a common disease?
the heterozygous genotype
Under some conditions, heterozygotes have greater reproductive success than homozygotes. What is this called?
Macroevolution can be defined as:
the appearance and extinction of species and the formation of major new branches on the tree of life
Lake Victoria is home to a group of related fishes known as cichlids. Hundreds of forms are present, differing slightly in their color patterns, habitat use, and feeding behavior. What is the best method for scientists to determine conclusively whether the fish are members of a population that has a lot of variation or members of entirely different species?
observing them together under natural conditions to see if they interbreed to produce fertile offspring
Speciation, or the formation of new species, is:
the bridge between microevolution and macroevolution
The ____ species concept is the most applicable to classifying species from the fossil record?
When a horse and a donkey mate, they produce infertile hybrids called mules. According to the ____ species concept, horses and donkeys are____
biological, different species
According to the biological species concept, a species is:
a group of populations whose members can interbreed in nature and produce fertile offspring
Often, the morphological species concept is used to define and describe species. Why?
this is the most convenient way of identifying species, and it is one of the few ways to identify fossil or asexual species
Two species of clams inhabit the same marine habitat along the Atlantic coast. One releases gametes into the water in early spring, and the second species releases gametes into the water in late summer. Which type of reproductive barrier is at work between these species?
Three species of frogs all mate in the same ponds, but they pair off correctly because they have different calls. This is a specific example of a ____ barrier, called _____
prezygotic, behavioral isolation
Individuals of different species living in the same area may be prevented from interbreeding by responding to different mating dances. This is called:
Two rodent populations become separated when a large canyon develops in a previously unbroken forest. When is allopatric speciation between the two populations complete?
when the two populations evolve to be different enough so that they are incapable of interbreeding successfully when given the opportunity to do so under natural conditions, allopatric speciation is complete
Uplift and formation of a mountain range divides a freshwater snail species into two isolated populations. Erosion eventually lowers the mountain range and brings the two populations together again, but when they mate, the resulting hybrids all produce sterile young. This scenario is an example of:
In the mountains of the southeastern United States, there are may similar but distinct salamander species that are restricted to particular mountaintops or ridge systems. They are found in patches of suitable high-elevation habitat, separated by unsuitable lowland areas. This distribution pattern indicates:
numerous allopatric speciation events
Sympatric speciation typically occurs through ___ and through _____
polyploidy in plants, habitat differentiation in animals
What do Dodd's experiments with fruit flies indicate?
reproductive barriers will arise most quickly if isolated populations experience and become adapted to differing environments
In a hybrid zone, ___ can occur if the reproductive barrier between two species is weak, as seen among cichilids in the murky waters of modern Lake Victoria.
Biologists have found more than 500 species of fruit flies on the various Hawaiian islands, all apparently descended from a single ancestor species. When this ancestor colonized the island chain, it found few competitors: many insect and fly families present in other regions are absent from the isolated Hawaiian islands. This example illustrates:
Earth probably formed ___ years ago, and the first life evolved as early as ____ years ago
4.5 billion, 3.9 billion
What is thought to have been the first step in the origin of life?
formation of organic monomers such as amino acids
Miller was the first to show that:
amino acids and other organic molecules could have been generated on a lifeless Earth
spheres with lipid membranes that concentrate solutes and can even carry out simple metabolic reactions if provided with enzymes
Hot sand, clay, or rock may have played an important role in the origin of life because:
evaporation of seawater from these surfaces could have concentrated monomers, leading to the formation of polymers through dehydration synthesis
A current leading hypothesis about the first system of inheritance in the earliest life forms involves:
self-replicating RNA molecules aided by ribozymes
About 2.2 billion years ago, oxygen released by early ____ became fairly abundant in the atmosphere, enabling the evolution of _____
photosynthesis, cellular respiration
The technique called radiometric dating is based on:
the steady, clocklike decay of certain radioactive isotopes over time
If you want to see a dinosaur, it would be best to set the controls of your time machine for the:
Mesozoic era, 150 million years ago
The correct order of the geologic eras, from most ancient to most recent, is:
Precambrian, Paleozoic, Mesozoic, Cenozoic
The Himalayas are an example of a mountain range formed as a result of:
the collision of two continental plates
Homeotic genes are responsible for:
determining the location and pattern of structural features such as limbs
Fish that were ancestral to the first amphibians may have had limbs that were used for moving through underwater vegetation, and were later adapted for use in walking on land. If so, the limbs were an example of:
The concept of ____ suggests that feathers originally evolved ____
exaptation, for some other function and only later became adapted for flight
The scientific study of the diversity of organisms and their evolutionary relationships is called:
Systematic biologists have used a wide variety of traits to reconstruct the phylogenies of particular groups of organisms. Which type of trait can also be analyzed to estimate the divergence times between taxa?