Chapter 17 Practice Flashcards: Darwin's Theory of Evolution

Practice questions and answers covering Darwin's voyage, historical influences on evolutionary thought, the mechanisms of natural selection, and modern evidence for evolution.

What was the primary scientific contribution made by Charles Darwin as a result of his voyage?

He developed a theory of biological evolution that offered a scientific explanation for the unity and diversity of life by proposing how modern organisms evolved through descent from common ancestors.

What were the three specific patterns of biodiversity that Darwin focused on during the voyage of the HMS Beagle?

(1) Species vary globally, (2) species vary locally, and (3) species vary over time.

Which three large flightless birds did Darwin observe to illustrate global variation across different continents?

Rheas in South America, ostriches in Africa, and emus in Australia.

How did Darwin use Galapagos tortoises to demonstrate that species vary locally?

He observed that different islands in the Galapagos had tortoises with different shell shapes, and people could identify which island a tortoise came from just by looking at its shell.

Which extinct animal did Darwin observe as a fossil that resembled the modern-day armadillo?

The glyptodont.

How do James Hutton and Charles Lyell describe the nature of geological processes in relation to Earth's history?

They concluded that Earth is extremely old and that the processes that changed Earth in the past, such as volcanoes and erosion, are the same processes that operate in the present.

Define the concept of "deep time" as introduced by James Hutton.

The idea that our planet’s history extends back over a time so long that it is difficult for humans to imagine.

What is the definition of uniformitarianism according to Lyell's Principles of Geology?

The way of thinking that states scientific explanations of past events must be in terms of processes that can be observed in the present.

What were the two primary hypotheses proposed by Jean-Baptiste Lamarck regarding how species evolve?

He suggested that organisms could change during their lifetimes by selectively using or not using body parts (acquired characteristics) and that these individuals could pass those acquired traits on to their offspring.

Why was Lamarck’s idea of "inheritance of acquired characteristics" eventually proven incorrect?

Traits acquired by individuals during their lifetime, such as the loss of a limb or building muscles through exercise, do not change the germ cells (sperm and egg) and therefore cannot be passed to offspring.

According to Thomas Malthus, what forces work against the unchecked growth of the human population?

War, famine, and disease.

What is artificial selection?

A process of selective breeding where nature provides inherited variations and humans select those variants they find useful, such as cows that produce the most milk or plants with larger fruit.

What are the three conditions under which natural selection occurs?

(1) The struggle for existence (more individuals born than can survive), (2) variation and adaptation (heritable variation affects the ability to survive and reproduce), and (3) survival of the fittest (fitness varies among individuals).

Define "fitness" in an evolutionary context.

How well an organism can survive and reproduce in its environment.

What is the principle of "descent with modification"?

The idea that living species are descended, with changes over time, from common ancestors.

What is biogeography?

The study of where organisms live now and where they and their ancestors lived in the past.

According to radioactive dating, approximately how old is the Earth?

Approximately $4.5 \text{ billion years}$ old.

What is the difference between homologous structures and analogous structures?

Homologous structures are shared by species and inherited from a common ancestor with the same basic bone structure (e.g., vertebrate limbs), while analogous structures serve similar functions but do not share a similar structure or development (e.g., the wing of a bee and the wing of a bird).

What are vestigial structures?

Structures inherited from ancestors that have lost much or all of their original size and function, such as the hipbone of a dolphin.

What evidence for evolution is found at the molecular level in almost all multicellular animals?

The set of homologous Hox genes, which determine the development of body parts like the head and tail.

According to the study by Peter and Rosemary Grant on Daphne Major, what happened to the finch population after a severe drought?

Birds with the largest beaks were more likely to survive because they could eat the remaining large, hard seeds, leading to an increase in average beak size in the population over time.