EVOLUTION
DARWIN’S THEORY OF NATURAL SELECTION
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Organisms inherit traits
|
|
|
Differences in genes create variation
|
|
|
Humans can breed organisms for specific traits
|
|
|
There is great variation among organisms
|
Detailed explanation-1: -Without genetic variation, a population cannot evolve in response to changing environmental variables and, as a result, may face an increased risk of extinction. For example, if a population is exposed to a new disease, selection will act on genes for resistance to the disease if they exist in the population.
Detailed explanation-2: -Yet there were two fundamental gaps in his chain of evidence. First, Darwin had no knowledge of the mechanism of heredity. Second, he had no visible example of evolution at work in nature.
Detailed explanation-3: -Evolution is not the same as adaptation or natural selection. Natural selection is a mechanism, or cause, of evolution. Adaptations are physical or behavioral traits that make an organism better suited to its environment. Heritable variation comes from random mutations.
Detailed explanation-4: -Some types of evidence, such as fossils and similarities between related living organisms, were used by Darwin to develop his theory of natural selection, and are still used today. Others, such as DNA testing, were not available in Darwin’s time, but are used by scientists today to learn more about evolution.