Concept of evolution
Evolution, in biology, complex process by which the characteristics of living organisms
change over many generations as traits are passed from one generation to the next. The
science of evolution seeks to understand the biological forces that caused ancient organisms
to develop into the tremendous and ever-changing variety of life seen on Earth today. It
addresses how, over the course of time, various plant and animal species branch off to
become entirely new species, and how different species are related through complicated
family trees that span millions of years.
Evolution provides an essential framework for studying the ongoing history of life on Earth.
A central, and historically controversial, component of evolutionary theory is that all living
organisms, from microscopic bacteria to plants, insects, birds, and mammals, share a
common ancestor. Species that are closely related share a recent common ancestor, while
distantly related species have a common ancestor further in the past. The animal most
closely related to humans, for example, is the chimpanzee. The common ancestor of
humans and chimpanzees is believed to have lived approximately 6 million to 7 million
years ago Evolutionary biologists attempt to determine the history of lineages as they
diverge and how differences in characteristics developed over time.
Early evolutionary theorists proposed that all of life on Earth evolved gradually from simple
organisms. Their knowledge of science was incomplete, however, and their theories left too
many questions unanswered. Most prominent scientists of the day remained convinced that
the variety of life on Earth could only result from an act of divine creation.
Darwin described the evolution of life as a process of natural selection. Life, he suggested,
is a competitive struggle to survive, often in the face of limited resources. Living things
must compete for food and space. They must evade the ravages of predators and disease
while dealing with unpredictable shifts in their environment, such as changes in climate.
Darwin offered that, within a given population in a given environment, certain individuals
possess characteristics that make them more likely to survive and reproduce. These
individuals will pass these critical characteristics on to their offspring. The number of
organisms with these traits increases as each generation passes on the advantageous
combination of traits. Outmatched, individuals lacking the beneficial traits gradually
decrease in number.
Natural selection is tied to traits that organisms pass from one generation to the next
Such traits are controlled by specific bits of biochemical instructions known as genes.
Genes are composed of individual segments of the long, coiled molecule called
deoxyribonucleic acid (DNA). They direct the synthesis of proteins, molecular laborers that
serve as building blocks of cells, control chemical reactions, and transport materials to and
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Evolution, in biology, complex process by which the characteristics of living organisms
change over many generations as traits are passed from one generation to the next. The
science of evolution seeks to understand the biological forces that caused ancient organisms
to develop into the tremendous and ever-changing variety of life seen on Earth today. It
addresses how, over the course of time, various plant and animal species branch off to
become entirely new species, and how different species are related through complicated
family trees that span millions of years.
Evolution provides an essential framework for studying the ongoing history of life on Earth.
A central, and historically controversial, component of evolutionary theory is that all living
organisms, from microscopic bacteria to plants, insects, birds, and mammals, share a
common ancestor. Species that are closely related share a recent common ancestor, while
distantly related species have a common ancestor further in the past. The animal most
closely related to humans, for example, is the chimpanzee. The common ancestor of
humans and chimpanzees is believed to have lived approximately 6 million to 7 million
years ago Evolutionary biologists attempt to determine the history of lineages as they
diverge and how differences in characteristics developed over time.
Early evolutionary theorists proposed that all of life on Earth evolved gradually from simple
organisms. Their knowledge of science was incomplete, however, and their theories left too
many questions unanswered. Most prominent scientists of the day remained convinced that
the variety of life on Earth could only result from an act of divine creation.
Darwin described the evolution of life as a process of natural selection. Life, he suggested,
is a competitive struggle to survive, often in the face of limited resources. Living things
must compete for food and space. They must evade the ravages of predators and disease
while dealing with unpredictable shifts in their environment, such as changes in climate.
Darwin offered that, within a given population in a given environment, certain individuals
possess characteristics that make them more likely to survive and reproduce. These
individuals will pass these critical characteristics on to their offspring. The number of
organisms with these traits increases as each generation passes on the advantageous
combination of traits. Outmatched, individuals lacking the beneficial traits gradually
decrease in number.
Natural selection is tied to traits that organisms pass from one generation to the next
Such traits are controlled by specific bits of biochemical instructions known as genes.
Genes are composed of individual segments of the long, coiled molecule called
deoxyribonucleic acid (DNA). They direct the synthesis of proteins, molecular laborers that
serve as building blocks of cells, control chemical reactions, and transport materials to and
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