Natural Selection and Evolution quiz #6 Flashcards
Natural Selection and Evolution quiz #6
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How do biologists define fitness?
Fitness is an organism's ability to survive and reproduce in its environment. What is natural selection?
Natural selection is the process by which the environment selects organisms with advantageous traits, increasing their fitness. What are the two main requirements for natural selection to occur?
The two main requirements are genetic diversity within a population and selective pressure for heritable traits that affect fitness. What does it mean for a trait to be heritable?
A heritable trait is one that can be passed from parents to offspring through genetic information. How did natural selection affect giraffe neck length over time?
Giraffes with longer necks could access more food and survived better, so over generations, the population evolved to have longer necks. How does natural selection relate to the phrase 'survival of the fittest'?
'Survival of the fittest' means that individuals best suited to their environment are more likely to survive and reproduce. How can natural selection cause evolution?
Natural selection can cause evolution by favoring certain heritable traits, leading to changes in the genetic makeup of a population over time. Describe an example of natural selection involving crickets and birds.
Birds more easily eat green crickets on a brown background, so brown crickets survive and reproduce more, leading to a population with mostly brown crickets. Why did the population of crickets become mostly brown over generations?
Brown crickets were less visible to predators and survived better, so their genes became more common in the population. How does natural selection explain why camels are well-suited to hot, dry climates?
Camels with traits that help them survive in hot, dry climates are more likely to survive and reproduce, so those traits become common in the population. How does natural selection lead to changes in a population's DNA?
Natural selection increases the frequency of advantageous genes in a population, changing its genetic makeup over time. What is the relationship between adaptation and evolution?
Adaptation is the result of natural selection, and over time, these adaptations can lead to evolutionary changes in a population. Why do populations, rather than individuals, evolve?
Evolution involves changes in the genetic makeup of populations over generations, not changes within a single individual's lifetime. How does natural selection maintain or increase genetic diversity?
Natural selection can maintain diversity if different traits are favored in different environments or circumstances. How does the process of natural selection result in the extinction of certain traits?
Traits that decrease fitness become less common and may disappear from the population if individuals with those traits do not survive or reproduce. How does the example of giraffes illustrate natural selection?
Giraffes with longer necks could reach more food, survived better, and passed on their genes, leading to a population of long-necked giraffes. How does natural selection contribute to the extinction of less fit individuals?
Less fit individuals are less likely to survive and reproduce, so their traits become rare or disappear. How does natural selection explain the diversity of life on Earth?
Natural selection leads to the evolution of different adaptations, resulting in a wide variety of species. How does camouflage increase an organism's fitness?
Camouflage helps organisms avoid predators, increasing their chances of survival and reproduction. How does natural selection act on phenotypes?
Natural selection acts on observable traits (phenotypes) that affect an organism's fitness. How can environmental changes affect natural selection?
Environmental changes can alter which traits are advantageous, shifting the direction of natural selection. How does natural selection lead to the loss of certain color traits in crickets?
Crickets with less camouflaged colors are eaten more often, so their color traits become less common or disappear. How does the concept of 'survival of the fittest' relate to reproduction?
The fittest individuals are those that survive and successfully reproduce, passing on their traits. How does natural selection explain why some animals are camouflaged?
Camouflaged animals are less likely to be seen by predators, survive better, and pass on their genes. Why do populations evolve rather than individuals?
Individuals do not change their DNA in response to the environment, but populations change as advantageous genes become more common over generations. How does natural selection affect the gene pool of a population?
Natural selection increases the frequency of advantageous genes and decreases the frequency of disadvantageous ones. What is the relationship between natural selection and adaptation?
Natural selection is the process that leads to adaptation by favoring traits that improve fitness. How does the environment 'select' for certain traits?
The environment creates conditions where some traits provide a survival or reproductive advantage, so those traits become more common. What is an example of a trait that increases fitness in a cold environment?
Thick fur in polar bears increases fitness by helping them survive in cold climates.
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