Chapter 9: Biological Evolution
Biological evolution is a fundamental concept in biology and is a frequent topic on the ENEM exam. Understanding evolution is essential to understanding the diversity and interconnectedness of life on Earth. In this chapter, we'll explore key concepts and theories of biological evolution, as well as its role in shaping life as we know it.
9.1 Theory of Evolution
The theory of evolution postulates that all species of living beings arose and developed from common ancestors through a process of natural selection over billions of years. Charles Darwin is the scientist best known for his work on this theory, although many others have contributed to its development.
9.2 Natural Selection
Natural selection is the process by which heritable traits that contribute to survival and reproduction become more common in a population, while traits that do not become less common. In other words, individuals that are more adapted to their environment are more likely to survive and reproduce, passing on their characteristics to the next generations.
9.3 Evolution and Adaptation
Adaptation is a key aspect of evolution. Species adapt over time in response to changes in their environment. These adaptations can be physical, like the shape of a bird's beak, or behavioral, like the migration patterns of a species. Adaptations are the result of natural selection acting on genetic variability within a population.
9.4 Evidence for Evolution
Evidence for evolution can be found in many areas of science, including paleontology, genetics, biogeography, and comparative anatomy. Fossils provide a record of extinct species and can show how species have changed over time. Genetics shows how species share common DNA sequences, suggesting a common ancestor. Biogeography studies the distribution of species and can show how species have adapted to different environments. Comparative anatomy studies the similarities and differences in the body structures of species, which may indicate evolutionary relationships.
9.5 Speciation
Speciation is the process by which new species form. This usually occurs when a population is divided by a geographic barrier, such as a mountain or a river, and the two populations adapt to different environments. Over time, the differences between the two populations can become so great that they become two distinct species.
9.6 Extinction
Extinction is the loss of a species or group of species. This can occur for a number of reasons, including climate change, disease, habitat loss, or competition with other species. Extinction is a natural part of evolution, but human activity has increased the rate of extinction in many groups of animals and plants.
9.7 Evolution and Society
Understanding evolution also has important social and ethical implications. For example, understanding evolution can help inform conservation and efforts to preserve biodiversity. Furthermore, evolution is often a topic of debate in education and policy, with some people questioning its validity or its inclusion in school curricula.
In summary, biological evolution is a key concept in biology and an important topic for the ENEM exam. We hope this chapter has given you a solid understanding of this complex and fascinating topic.
