The Darwinian Revolution

descent with modification

The outcome of natural selection: modifications accumulated from generation to generation that can ultimately result in new species.

biogeography

Study of the geographical distribution of species.

Who independently formulated the hypothesis of natural selection before Darwin published his work

Alfred Russel Wallace

What was Darwin's interest in joining the mission of the HMS beagle

As a companion to the captain of the ship assisting in surveying the geology and biology of sites primarily in South America.

Charles Darwin

British naturalist who developed the theory of evolution by natural selection in parallel with Alfred Russel Wallace.

evolution

Change in allele frequencies in a population over time.

Alfred Russel Wallace

Contemporary to Darwin; co-developed the hypothesis of natural selection and was a famed biogeographer.

Describe the historical academic context of Darwin's publications

Darwin was influenced by Charles Lyell's writings about uniformitarianism and maintained a collegial relationship with the geologist. Darwin delayed publication of his hypothesis of natural selection to gather extensive supporting data, but when Alfred Russel Wallace independently proposed the mechanism of natural selection, Lyell arranged for the simultaneous presentation of both works. Wallace deferred primary intellectual ownership to Darwin based on Darwin's more extensive development of the idea.

Describe Darwin's arguments for the theory of natural selection to explain descent with modification

Darwin's arguments for the mechanism of natural selection to explain descent with modification are based on the observations that individuals in a population vary in heritable traits, a population produces more offspring than can survive, and thus offspring compete for limiting resources. Darwin presented the logical inference that individuals with traits that confer higher fitness will be represented by a higher proportion of offspring that survive to reproduce in the next generation. Over multiple generations, these adaptive traits will accumulate in a population, and the population will evolve.

Explain how Darwin's research and observations of the natural world affected his ideas about species

Darwin's contemplations of the natural systems he observed and the collections he accumulated during the surveying mission of the HMS Beagle provided the initial evidence on which he based his hypothesis of descent with modification.

Generalize the effect of Darwin's ideas on science and society

Darwin's work has influenced generations of scientists, and the resulting theory of evolution has been refined and supported and is now considered the unifying concept for the life sciences. Even though Darwin's ideas were not popular with Christian church leaders at first, most mainstream religions now accept them. However, controversies regarding the teaching of evolution are still raging in some regions.

What influenced Darwin's ideas about the evolution of species during his journey on the surveying mission of the HMS Beagle

His experience following a major earthquake in Chile.

Which observations formed the basis of Darwin's argument for the theory of natural selection explaining descent with modification outlined in On the Origin of Species

Individuals vary in heritable traits and produce more offspring than are able to survive, and those offspring compete for limited resources.

mechanism that drives natural selection

Individuals with traits better suited to their environments are more likely to survive and reproduce; therefore, their offspring are more likely to inherit these adaptive traits.

Which of the following people proposed a mechanism of evolution before Charles Darwin did

Jean-Baptiste Lamarck

natural selection

Mechanism of evolution theorized by Darwin and Wallace. Individuals with heritable traits that allow the highest fitness will have their genes more represented in subsequent generations.

uniformitarianism

Theory that observable processes in the present have always been taking place and can also explain activity in the past.

Imagine that you are hiking up a mountain and you notice that the trees are gradually becoming larger as you walk. You hypothesize that large size is an adaptation to colder habitats. Which of the following would NOT be informative in supporting or rejecting this hypothesis

measuring as many trees as possible along the mountain and plotting a graph of the relationship between temperature and tree size.