Chapter 14: Darwin and Evolution Flashcards
What is evolution?
A change in the genetic composition of a population over time.
What is adaptation?
A behavioral, physiological, or morphological feature of an organism that increases survival or reproductive success.
Explain the mechanism for evolutionary change proposed by Jean Baptise Lamarck. (2 parts)
Lamarck believed in the inheritance of acquired traits. Which basically means that parents acquired traits in their lifetime, and passed them to their offspring.
Why has modern biology rejected Lamarck’s theories? (2 parts)
His theories were not supported, because people who were blinded in an accident would have blind children. Furthermore, phenotypic changes acquired during the lifetime do not result in genetic changes that can be passed to offspring.
Describe how Darwin’s observations on the voyage of the HMS Beagle led him to formulate and support his theory of evolution.
Darwin’s conclusions that organisms are related through common descent and that adaptation to various environments results in diversity were based on several types of data, including his study of geology, fossils, and geography.
Explain what Darwin meant by “descent with modification”. (2 parts)
Living forms descended from extinct forms known only by the fossil record. Species are not fixed; instead they change over time.
Explain what evidence convinced Darwin that species change over time.
Darwin collected fossils that differed from modern animals.
What observations lead Darwin to propose natural selection as a mechanism for evolutionary change? (4 parts)
- The members of a population have heritable variations.
- The population produces more offspring than the resources of an environment can support.
- The individuals that have favorable traits survive and reproduce to a greater extent than those that lack these traits.
- Across generations, a larger proportion of the population possesses the favorable traits, and the population becomes adapted to the environment.
Distinguish between artificial selection and natural selection. (2 parts)
Natural selection is the basic idea that a population can change over generations if individuals that possess certain heritable traits produce more offspring. In artificial selection, humans intentionally alter the physical traits of domesticated species.
Explain why an individual organism cannot evolve.
In a population, there is a variety of traits. In order for evolution to occur, the most valued traits (determined by the environment) will be favored amongst new generations.
Describe how natural selection favors the evolution of drug resistant pathogens.
If a drug was made to destroy certain pathogens, but some were more resistant to the drug than others; Some pathogens would be naturally selected (possess favorable traits) to have a higher chance of survival in the hypothetical environment.
Explain how the fossil record may be used to test our current understanding of evolutionary patterns.
The fossil record can be used to analyze the different variations of a species that have existed in the past, approximately when they dwelled the earth, and finally, with a bit of deductive reasoning, why they’ve died.
Explain how the existence of homologous and vestigial structures can be explained by Darwin’s theory of natural selection.
Homologous structures exist, because natural selection dictated the variations of similar species in different environments. Vestigial structures exist, because certain structures that existed in ancestral species were no longer needed in the population to be fit.
Explain how evidence from biogeography supports the theory of evolution by natural selection.
Similar organisms exist on separate continents. These organisms vary slightly, by traits that were / are favored by their respective environments.
What are two forms of evidence of evolution? How do they serve as evidence? (2 parts)
- The fossil record shows us the ancestry, and evolution of modern organisms.
- Biogeography shows us that populations with both homologous structures, and varied vestigial structures exist in different environments.
