Evolution Lecture Notes

A set of question-and-answer flashcards covering spontaneous generation, origin of life experiments, endosymbiosis, adaptation, evidence for evolution, Lamarck’s and Darwin’s theories, and natural selection.

What theory claimed that living creatures could arise from non-living matter, and who finally disproved it?

The theory of spontaneous generation; it was disproven by Louis Pasteur.

Which 1950s experiment simulated early-Earth conditions to produce organic molecules, and what did it show?

The Miller–Urey experiment; it demonstrated that a reducing primordial atmosphere could synthesize the organic building blocks of life.

What does the endosymbiotic theory propose about the origin of eukaryotic cells?

Eukaryotic cells arose through symbiosis when different prokaryotes became incorporated as organelles such as mitochondria and chloroplasts.

Which ancestral bacteria are thought to have become mitochondria?

Aerobic bacteria.

Which ancestral bacteria are thought to have become chloroplasts?

Photosynthetic bacteria.

Approximately how long ago did prokaryotes begin evolving internal membranes leading to eukaryotes?

About 2 billion years ago.

Define an adaptation in evolutionary terms.

An inherited trait or set of traits that increases an organism’s chances of survival and reproduction in a specific environment.

What is evolution?

The cumulative change in characteristics of populations of organisms across successive generations.

In biology, what is a population?

A group of individuals of the same species living in a given area at a specific time.

Give one example each of direct and indirect evidence for evolution.

Direct: fossils. Indirect: DNA/molecular comparisons (others include embryology, vestigial structures, etc.).

In what type of rock are fossils most commonly found?

Sedimentary rock.

How does relative dating of fossils differ from absolute (radioactive) dating?

Relative dating estimates age by a fossil’s position in rock layers, whereas absolute dating uses radioactive isotopes to assign a numerical age.

Name three kinds of indirect evidence for evolution other than DNA/molecular data.

Embryological similarities, vestigial structures, and homologous or analogous structures.

What are vestigial structures?

Reduced or non-functional anatomical features that were functional in an organism’s ancestors.

What is a homologous structure and what kind of evolution does it illustrate?

A structure with common ancestry but potentially different functions, illustrating divergent evolution.

What is an analogous structure and what kind of evolution does it illustrate?

A structure with similar function but different ancestry, illustrating convergent evolution.

Who proposed the theory involving use and disuse of organs, and in what year?

Jean-Baptiste Lamarck in 1809.

According to Lamarck, how were acquired characteristics thought to be inherited?

Traits developed during an organism’s lifetime were believed to be passed on to its offspring.

What key flaw invalidated Lamarck’s theory?

Acquired traits are not heritable; only genetic information is passed to offspring.

On which ship did Charles Darwin undertake his five-year voyage?

The H.M.S. Beagle.

What is the title of Darwin’s 1859 book that presented his theory of evolution?

On the Origin of Species.

Which island group provided crucial observations for Darwin’s theory?

The Galápagos Islands.

Name two intellectual influences that shaped Darwin’s thinking and how they helped.

Charles Lyell’s idea of an ancient, slowly changing Earth suggested time for evolution; Thomas Malthus’s doctrine on population limits highlighted competition for resources.

What does the term "struggle for existence" refer to in natural selection?

Competition among organisms for limited resources due to high birth rates and scarce supplies.

According to natural selection, what decides which individuals pass on their genes?

Individuals with heritable traits that increase fitness are more likely to survive and reproduce.

Define artificial selection and give one example mentioned in the notes.

Human-directed breeding for desired traits; e.g., farmers breeding dairy cows that produce large amounts of milk.

What does the fossil record reveal when some fossils resemble living species while others look very different?

It shows that species change over time and that entirely new forms can arise while others go extinct.

What does the diversity observed even between identical twins illustrate?

Genetic variation exists among all organisms, contributing to diversity within species.

What is the Malthusian doctrine, and how did Darwin apply it to nature?

It states that famine, disease, and war limit human population growth; Darwin applied it by recognizing that most offspring in nature die, leaving only some to reproduce.

Why was Darwin puzzled by species distribution across similar environments?

Some unrelated species occupy similar habitats while closely related species inhabit different areas, indicating historical patterns of evolution and migration.