Analysis of Biological Diversification Chapter 2

What did James Hutton and Charles Lyell suggest about Earth's age?

Hutton and Lyell argued the Earth is very old. Lyell introduced uniformitarianism—slow processes like erosion shape the Earth over millions of years.

How did Darwin use uniformitarianism in his theory?

He used it to support the idea that evolution is slow, ongoing, and happens over long time scales.

Define gradualism and catastrophism.

Gradualism: slow processes shape Earth's features. Catastrophism: sudden, large-scale events shape geography.

What was Aristotle’s early evolutionary idea?

He proposed the “Great Chain of Being,” a static hierarchy of organisms with no evolution.

What were Erasmus Darwin’s evolutionary ideas?

He believed in a “single living filament” evolving over time and common ancestry, but lacked a mechanism for how evolution occurred.

What idea did Robert Chambers promote in Vestiges?

He focused on population-level change over time, but failed to explain how new species arise.

What was William Paley’s watchmaker analogy?

He compared organisms’ complexity to a watch, arguing for an intelligent designer behind life’s complexity.

What ideas did Lamarck propose?

Lamarck believed species evolved from simpler forms and that acquired traits were inherited—an idea now proven false.

What concept did Patrick Matthew propose that was similar to Darwin's?

He proposed a natural selection-like idea ("circumstance-adaptive law") but lacked evidence and wasn’t widely read.

What were Darwin’s two major insights?

Natural selection (environment favors beneficial traits) and common ancestry (species evolve from shared ancestors).

Why was Darwin given more credit than Wallace?

He had more data, worked on his theory for 20 years, and Wallace let Darwin publish first out of respect.

What is artificial selection and why did Darwin start with it?

Humans breed organisms for desired traits; Darwin started with it because it was familiar to his readers (e.g., pigeons).

Define domestication and domestication syndrome.

Domestication: selecting animals for human use. Syndrome: shared traits in domestic animals (e.g., floppy ears, less stress hormones).

Describe the Belyaev and Trut fox experiment results.

At generation 6, foxes had floppy ears and curly tails. By generation 15, their stress hormone levels were half of wild foxes.

What were Darwin’s definitions of variety and species?

Variety = small differences within species; species = accumulated variation. He saw no sharp distinction, just a continuum.

What was Darwin’s explanation of natural selection?

Nature selects advantageous traits over time. Dallinger’s protists adapted to 66°C but couldn’t survive initial temps, proving change.

What did Thomas Malthus argue about populations?

Populations grow faster than resources. Without limits like disease or war, resources would be exhausted.

What’s the difference between transformational and variational change?

Transformational: all individuals change. Variational: individuals differ, and advantageous traits become more common.

How did Darwin and Lamarck differ in their view of species origins?

Lamarck: divine design and inherited traits. Darwin: natural selection and chance drive evolution.

What does “hierarchical patterns of similarity” mean?

Organisms cluster by similarity. Example: wolves and foxes closer than badgers; all more related than to a raven.

How does biogeography support evolution?

Organisms in similar habitats are more alike. Oceans can be crossed by things like saltwater-resistant seeds.

What three problems did Darwin face after publishing?

1) Complex structures couldn’t form gradually, 2) Useless traits exist, 3) Natural selection reduces variation, which is needed for evolution.

How did Russians and the English respond to Darwin’s book?

Russians accepted common descent, but disliked Malthus. English accepted evolution, but not natural selection.

What experiment laid the groundwork for modern synthesis?

Mendel’s pea plant experiments showed traits were inherited. Led to understanding genes and variation.

What did Mendelians and biometricians believe?

Mendelians: evolution is large jumps. Biometricians: it’s gradual. Modern synthesis combines both with genetics and selection.

What are the key ideas of modern synthesis?

Traits are inherited via genes, mutations cause variation, not all mutations are harmful, selection acts on phenotypes, and polygenic traits exist.