Evolution is the process by which populations accumulate inherited changes over time. Which of the following mechanisms drives evolution?
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fossilization
natural selection
nitrogen fixation
plate tectonics
natural selection
In a population of short, ground-dwelling animals, some offspring were produced that were approximately 1 cm taller than others in the population. This group was able to reach slightly higher vegetation than the rest of the population. When these animals grew up, they were able to produce more offspring than other animals in the population. This pattern, where the tallest animals were more likely to survive and reproduce, continued over several generations.Eventually, after many generations, all members of the population were at least 20 cm taller than animals of the original population had been. What does this illustrate?
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Only major differences between parents and offspring can result in future generations that are very different from their ancestors.
Slight differences between parents and offspring can eventually result in future generations that are very different from their ancestors.
Ground-dwelling animals would survive better if they evolve to be shorter.
Biological change does not apply to ground-dwelling animals.
Slight differences between parents and offspring can eventually result in future generations that are very different from their ancestors.
A deer is born with the ability to smell predators better than the other deer in its population. As a result, this deer has several seconds of warning every time wolves or other predators attack. This trait may be selected by natural selection because it increases the deer's _______.
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ability to survive
sense of safety
ability to select mates
ability to find food
ability to survive
Biological change over time accounts for the diversity of species. This diversity
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occurs in the animal kingdom but not in the plant kingdom.
develops through gradual processes over many generations.
occurs in the plant kingdom but not in the animal kingdom.
develops only through sudden change over a single generation.
develops through gradual processes over many generations.
The process of natural selection favors certain characteristics in organisms, while it selects against other characteristics.What would happen if there was zero variation between all of the organisms on Earth?
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Natural selection would operate faster.
Organisms would evolve to increase variety.
Less food would be available.
Evolution through natural selection would not occur.
Evolution through natural selection would not occur.
Below is a diagram indicating the limb bones of a human, a crocodile, a bat, a whale, and a bird. Similar bones are highlighted in the same colors. Humans, crocodiles, bats, whales, and birds have similar limb bones. What do these similarities suggest?
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Humans, crocodiles, bats, whales, and birds evolved from a common ancestor.
Humans, bats, and crocodiles share an ancestor with whales but not with birds.
A similar limb structure evolved in each species independently and by chance.
The common ancestor of a human and a bird was a whale.
Humans, crocodiles, bats, whales, and birds evolved from a common ancestor.
The diagram below shows illustrations of fossilized forefeet and molar teeth from horses that lived during different time periods. The diagram also shows how the body shape and size of horses has changed over time. This fossil evidence provides support for the idea that
modern organisms have evolved from earlier species.
changes can only occur in a species' feet and teeth.
ancient species are now extinct and modern species have spontaneously generated.
modern organisms within a species are identical to their ancestors.
Modern organisms have evolved from earlier species.
The phylogenetic tree below shows the evolutionary relationships among several organisms. What does the diagram imply about the peafowl and field mouse?
They are unrelated.
They share a recent common ancestor.
They share a remote common ancestor.
They did not evolve from older forms of life.
They share a remote common ancestor.
Cladistic diagrams, or cladograms, can be used to show evolutionary relationships. An example of a cladistic diagram appears below. According to the diagram, which of the following animals is most closely related to crocodiles?
rodents
amphibians
birds
primates
birds
The following diagram shows the relationships among certain types of organisms. The red lines represent a common ancestor that was the first organism to have the trait listed. For example, sea stars do not have spinal cords, but the organisms that come after (to the right) do have a spinal cord. Based on the diagram, which of the organisms below is most closely related to the bullfrog?
shark
sea star
perch
lamprey