Darwin Lecture #2

Who developed the theory of evolution by natural selection?

Charles Darwin

What did many people believe about species before Darwin?

They were fixed and did not change

What was James Hutton's major contribution?

Gradual geological change over long periods

What was Lamarck's important contribution?

He proposed that species could change over time

What was George Cuvier known for?

Extinction

What did Charles Lyell argue?

Geological processes today also occurred in the past

What was Thomas Malthus's main idea?

Populations can grow faster than available resources

What does natural selection act on?

Existing variation

Which is an example of variation?

Some birds having larger beaks than others

What does "heritable" mean?

A trait can be passed from parents to offspring

Why do organisms compete?

More offspring are produced than the environment can support

Which BEST describes natural selection?

Individuals with beneficial heritable traits tend to reproduce more

Which statement about evolution is correct?

Populations change over generations

What does "survival of the fittest" mean?

The organism with the greatest reproductive success is more fit

Who independently developed the idea of natural selection?

Wallace

What was special about Darwin and Wallace?

They independently came up with natural selection

What did Darwin's finches demonstrate?

Different environments can favor different traits

Why did finches on different Galápagos Islands have different beaks?

Different food sources favored different beak shapes

What is artificial selection?

Humans choose which organisms reproduce

Which is an example of artificial selection?

Dogs being selectively bred for certain traits

Which sequence BEST describes natural selection?

Variation → heritability → competition → differential reproduction → population change

A population of beetles contains green and brown beetles. Birds eat more green beetles because they are easier to see. Over many generations, there are more brown beetles. What happened?

Natural selection changed the population

Which statement is FALSE?

Organisms develop traits because they need them.

Why were Hutton and Lyell important to Darwin?

They showed that Earth had a very long history

Which scientist's ideas helped Darwin understand competition among organisms?

Thomas Malthus

Why are specimens such as Archaeopteryx, which is considered to be an intermediate between dinosaurs and birds, not intermediate for all characters?

Different characters evolve at different rates at different times

The supercontinent that existed 250 million years ago was

Pangaea

Which of the following fossils is transitional between ancient whales and modern whales? (this is mentioned in the Darwin lecture...)

Basilosaurus isis

The finches observed by Darwin on the Galapagos Islands are likely the result of

evolutionary adaptation of a single finch species filling the niches normally occupied by other birds on the mainland

Vestigial structures include all of the following except

dinosaur feathers

vestigal structures are

body parts that were useful in an ancestor but have little or no important function today.

During the time of Darwin, the mechanism of transmission from parents to offspring was thought to be due to

blending inheritance

What is blending inheritance?

Traits from the two parents mix together in the offspring

Variation in traits within a population is essential in evolution so long as

the trait is heritable

The geologist that influenced Darwin by providing a frame of geologic time was:

Charles Lyell

One line of evidence that helped convince Darwin that species can change over time was

his observations of marine fossils on cliffs that were hundreds of meters above sea level

Distantly related animals are often striking similar in morphology (e.g dolphins and tuna). This is because of:

similar selection pressures.

Evolution is a process that is driven in large part by the process known as

natural selection

Much of the evidence in support of Darwin's original ideas was obtained on the continent of (and island surrounding)

South America

Disruptive selection favors

phenotypes at both ends of the range

Which example best describes disruptive selection?

Small and large beaks are favored, while medium-sized beaks are less successful

Human birth weight is an example of

stablizing selection

What is stabilizing selection?

Favors individuals with intermediate traits

What is directional selection?

Favors one extreme phenotype

What is intersexual selection?

Individuals choose mates based on desirable traits

What is intrasexual selection?

Individuals of the same sex compete with each other for mates

The disease sickle-cell anemia is maintained at relatively high frequencies in populations in Africa and Asia by:

heterozygote advantage

What is genetic drift?

Random changes in allele frequencies, especially in small populations

What is gene flow?

Movement of alleles between populations when individuals or their gametes move