bio chapter 23 (2nd slides, or 2nd chapter) part 1

Who first proposed the idea of evolution?

Jean-Baptiste Lamarck

What did many scientists observe before Darwin published his theory?

Life had changed over time

Who wrote Principles of Geology?

Charles Lyell

In what year did Lamarck publish his ideas about evolution?

1809

Who independently proposed natural selection in 1858?

Alfred Russel Wallace

What was Darwin’s major contribution to evolutionary theory?

The mechanism of natural selection

Which statement best summarizes Lamarck’s idea about evolution?

Traits acquired during an organism’s life can be inherited

How did Charles Lyell’s Principles of Geology influence evolutionary thinking?

It suggested geological processes occur gradually over long periods

What makes Darwin’s contribution to evolutionary theory distinct from his predecessors?

He provided a mechanism — natural selection — explaining how evolution occurs

Why is Alfred Russel Wallace significant in the history of evolution?

He independently proposed natural selection around the same time as Darwin

What concept did Jean-Baptiste Lamarck propose?

Inheritance of acquired characteristics

According to Lamarck, how did giraffes get long necks?

Stretching their necks during life and passing it to offspring

How did Darwin explain the evolution of long necks in giraffes?

Natural selection favored giraffes with preexisting longer necks

What is genetic variation?

Differences in alleles within individuals in a population

What is the ultimate source of genetic variation?

Mutation

What does Hardy–Weinberg equilibrium describe?

Allele and genotype frequencies remain constant under certain conditions

Which of the following is NOT a condition for Hardy–Weinberg equilibrium?

High rate of natural selection

What is gene flow?

Movement of alleles between populations through migration or mating

Which scenario best illustrates genetic drift?

Random fluctuation of alleles in a small population

What type of selection favors individuals with extreme traits at both ends?

Disruptive selection

What is stabilizing selection?

Favors intermediate phenotypes and reduces extremes

In the water boatman example, what is positive frequency-dependent selection?

Common phenotypes are favored

Why does the sickle cell allele persist in populations?

Heterozygotes are resistant to malaria

What is the difference between natural selection and evolution?

Natural selection is a process; evolution is the outcome of change over time

In directional selection, what happens to the population?

One extreme phenotype increases in frequency

What happens in a bottleneck effect?

Drastic reduction in population leads to loss of genetic variability